CN120155176A - Anti-aging high-activity CO oxidation catalyst and preparation method thereof - Google Patents
Anti-aging high-activity CO oxidation catalyst and preparation method thereof Download PDFInfo
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Abstract
The invention discloses an anti-aging high-activity CO oxidation catalyst and a preparation method thereof, and relates to the technical field of catalysts. The technical scheme is that the composite material comprises, by mass, 0.1-2% of iridium-ruthenium alloy active component, 80-90% of tantalum-doped zirconia carrier and 10-20% of composite auxiliary agent, wherein the composite auxiliary agent is a composite oxide of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is (1-3): 1. According to the invention, through optimizing the active components, the carrier and the auxiliary agent system and combining with an innovative preparation process, the CO conversion rate and the sulfur poisoning resistance of the catalyst are obviously improved.
Description
Technical Field
The invention relates to the technical field of catalysts, in particular to an anti-aging high-activity CO oxidation catalyst and a preparation method thereof.
Background
The steel sintering process is used as a key link in steel production, and the generated flue gas contains a large amount of harmful gases such as carbon monoxide (CO), sulfur dioxide (SO 2) and the like. These gases not only cause serious pollution to the environment, but also pose a threat to human health. In order to effectively purify these harmful gases, CO oxidation catalysts having noble metals such as platinum (Pt) and palladium (Pd) as cores have been conventionally used.
However, conventional Pt/Pd noble metal catalyst systems have a number of problems in practical applications. First, noble metals such as Pt, pd and the like are expensive, so that the cost of the catalyst is high, and the production cost of iron and steel enterprises is increased. Secondly, these catalysts are more sensitive to sulfur poisoning, are easily deactivated in sulfur-containing environments, and reduce catalytic efficiency and service life. Moreover, the lack of high temperature stability is a major disadvantage, and in a high temperature sintering environment, the catalyst is easy to undergo structural change or sintering, and further affects the catalytic performance.
In addition to the above problems, the support and promoter systems of conventional catalysts also have limitations in the ability to regulate oxygen vacancies. Oxygen vacancies are an important component of the catalyst surface active sites and play a critical role in the adsorption and activation of CO. The carrier and the auxiliary agent system have limited capability of regulating oxygen vacancies, so that the catalytic activity of the catalyst is insufficient, and the requirement of efficient purification is difficult to meet.
In view of the above problems, the development of a CO oxidation catalyst which is efficient, stable and sulfur poisoning resistant has important practical significance and scientific research value.
Disclosure of Invention
The invention aims to solve the technical problems of overcoming the defects of the prior art and providing an anti-aging high-activity CO oxidation catalyst and a preparation method thereof, wherein the CO conversion rate and the sulfur poisoning resistance of the catalyst are obviously improved by optimizing an active component, a carrier and an auxiliary agent system and combining an innovative preparation process.
The technical scheme of the invention is as follows:
On one hand, the invention provides an anti-aging high-activity CO oxidation catalyst which comprises, by mass, 0.1-2% of iridium-ruthenium alloy active components, 80-90% of tantalum-doped zirconia carriers and 10-20% of composite assistants, wherein the composite assistants are composite oxides of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is (1-3): 1.
Preferably, in the iridium-ruthenium alloy active component, the mass ratio of iridium to ruthenium is 1 (1-5).
Preferably, the molar ratio of zirconium to tantalum in the tantalum doped zirconia support is (9-19): 1.
On the other hand, the invention provides a preparation method of the anti-aging high-activity CO oxidation catalyst, which comprises the following steps:
s1, preparing a carrier, namely preparing a tantalum-doped zirconia carrier through a sol-gel combustion synthesis method;
s2, pretreatment of a carrier, namely calcining the tantalum-doped zirconia carrier by adopting a gradient calcining method, firstly raising the temperature to 400-450 ℃ at the rate of 5-10 ℃ per minute, preserving heat for 1-2 hours, then raising the temperature to 550-600 ℃ at the rate of 3-5 ℃ per minute, and preserving heat for 2-3 hours;
S3, impregnating the composite auxiliary agent, namely carrying out primary impregnation on the tantalum-doped zirconia carrier by taking ammonium tartrate as a complexing agent to carry MoO 3, and carrying out secondary impregnation by adopting an ultrasonic auxiliary microwave drying method to carry Nb 2O5 on the tantalum-doped zirconia carrier;
s4, loading the active component, namely loading the iridium ruthenium alloy active component on the tantalum doped zirconia carrier impregnated with the composite additive by adopting a supercritical CO 2 fluid deposition method, and obtaining the anti-aging high-activity CO oxidation catalyst.
Preferably, in step S1, the preparation of the tantalum doped zirconia support by the sol-gel combustion synthesis method comprises the following steps:
(1) Dissolving metal salt, namely dissolving zirconyl nitrate and tantalum pentachloride (TaCl 5) in deionized water, stirring to be transparent, adding a combustion agent, continuously stirring, adjusting the pH value of the solution to 3-4, and promoting the complexing reaction to form uniform sol;
(2) Gelling and drying, namely placing the solution in a water bath at 80-90 ℃, continuously stirring and evaporating to be in a viscous gel state, transferring to an oven and drying to obtain a porous xerogel precursor;
(3) The combustion synthesis comprises grinding porous xerogel precursor into powder, ensuring uniformity, placing the powder in a refractory crucible, heating to 250-300 ℃ in a muffle furnace at 5-10 ℃ per min, and triggering self-propagating combustion reaction;
(4) High temperature calcination, namely continuously heating to 600-800 ℃, and preserving heat for 2-4 hours to completely decompose organic matters to obtain tantalum doped zirconia crystals;
(5) And cooling and grinding, namely naturally cooling to room temperature, and grinding again to obtain the tantalum-doped zirconia carrier.
Preferably, in the step (1), the mass ratio of the burning agent to the glycine and the citric acid is 1 (2-3), the mole ratio of the zirconyl nitrate and the tantalum pentachloride is (9-19): 1, and the mole ratio of the burning agent to the total mole number of the Zr 4+、Ta5+ is (1.5-2): 1.
Preferably, in step (2), the drying temperature is 100-110 ℃ and the drying time is 10-12 hours.
Preferably, in step S3, the first impregnation of the load MoO 3 comprises the following steps:
(1) Preparing a solution, namely preparing an ammonium molybdate ((NH 4)6Mo7O24·4H2 O) precursor solution with the concentration of 0.1-0.5mol/L by using deionized water, adding ammonium tartrate ((NH 4)2C4H4O6) into the solution according to the molar ratio of the ammonium tartrate to Mo of (1-2), stirring the solution until the ammonium tartrate is completely dissolved, adjusting the pH value of the solution to 3-5, and inhibiting MoO 3 from rapidly hydrolyzing;
(2) The method comprises the steps of (1) carrying out equal volume impregnation, namely dropwise adding a precursor solution into a tantalum-doped zirconia carrier until the pore volume is saturated;
(3) Standing and aging, namely standing for 6-12 hours at room temperature in a closed environment to promote uniform adsorption of the Mo complex;
(4) Drying and roasting at 60-80deg.C for 12 hr, slowly removing water, calcining at 400-500deg.C in muffle furnace for 4-5 hr at a heating rate of 2-3deg.C/min to form MoO 3 crystal phase;
The secondary impregnation load Nb 2O5 includes the steps of:
1) Preparing an oxalic acid solution into an ammonium niobium oxalate (NH 4NbO(C2O4)2·nH2 O) precursor solution with the concentration of 0.05-0.2 mol/L;
2) Ultrasonic assisted impregnation, namely immersing a tantalum doped zirconia carrier loaded with MoO 3 precursor into niobium oxalate precursor solution, and immersing in a 40-50kHz ultrasonic tank for 30-60min;
3) Drying by microwave enhanced drying, namely drying by adopting a microwave pulse mode, starting 30-40s, stopping 15-20s, and enabling the power to be 300-600W until the drying is completed;
4) Decomposing and crystallizing, namely presintering for 2-3 hours at 200-250 ℃, decomposing organic matters, and then heating to 450-550 ℃ and calcining for 3-4 hours to form Nb 2O5.
Preferably, in step S4, the supercritical CO 2 fluid deposition method includes the steps of:
(1) Preparing iridium ruthenium alloy precursor solution, namely preparing iridium acetylacetonate (Ir (acac) 3) and ruthenium acetylacetonate (Ru (acac) 3) solution by methanol, dissolving the solution with the methanol accounting for 5-10vol.% under the assistance of ultrasound until the solution is clear and has no precipitate, filtering the solution by an organic filter membrane with the thickness of 0.22-0.25 mu m, and removing undissolved impurities;
(2) Pre-activating, namely treating the tantalum doped zirconia carrier loaded with the composite additive for 1-22 hours at the temperature of 250-350 ℃ in H 2/N2(5vol.％H2) atmosphere to enhance the surface hydroxyl activity;
(3) Placing the carrier in a reaction kettle under the conditions of 40-60 ℃ and 10-15MPa, and CO 2 flow rate of 0.5-2L/min, introducing pure CO 2 to supercritical state, and maintaining for 30min to remove air;
(4) Injecting a precursor, namely injecting an iridium-ruthenium alloy precursor solution into a reaction kettle through a high-pressure pump to ensure that CO 2 and the precursor are fully mixed;
(5) Dynamic impregnation, namely maintaining supercritical conditions for 2-4 hours under stirring conditions to enable the precursor to be uniformly adsorbed on the carrier pores;
(6) Decompression deposition, namely releasing pressure (the speed is less than or equal to 0.5 MPa/min), gradually gasifying CO 2, and directionally depositing a precursor on the surface of a carrier;
(7) Hydrogen reduction, namely introducing H 2/Ar mixed gas (H 2 accounts for 5-10 vol%) into a tubular furnace, heating to 300-400 ℃ at 2 ℃ per min, preserving heat for 2-3H to reduce Ir 3+、Ru3+ into a metal state, further heating to 450-550 ℃, preserving heat for 1-2H, and promoting alloying.
Compared with the prior art, the invention has the following beneficial effects:
1. The invention obviously improves the CO conversion rate and the sulfur poisoning resistance of the catalyst by optimizing the active components, the carrier and the auxiliary agent system and combining with an innovative preparation process, and is particularly suitable for high-humidity and high-sulfur sintering flue gas environments.
2. According to the invention, the Ir-Ru alloy is selected to replace conventional Pt/Pd as an active component, a bimetal interface structure can be formed by the Ir-Ru alloy by utilizing the electronic synergistic effect of the high stability of Ir and Ru, a unique difunctional active site can be provided by the Ir-Ru atom pair with exposed surface, and the dynamic balance of CO adsorption strength and oxygen activation capacity is realized by the geometric-electronic double synergistic effect, and meanwhile, the high activity, stability and anti-middle toxicity are simultaneously considered. In addition, the Ir-Ru alloy inhibits SO 2 adsorption through electronic regulation and control, and the interface synergistically promotes dynamic desorption of sulfur oxides, and the high stability of Ir prevents deep penetration of sulfate, SO that the performance of the Ir-Ru alloy is obviously superior to that of a traditional Pt/Pd catalyst in SO 2 poisoning resistance. Meanwhile, the invention develops a tantalum-doped zirconia carrier, and stable oxygen defect sites are generated through Ta 5+ induction, SO that the oxygen activating capacity of the catalyst is enhanced, SO 2 is promoted to be oxidized into SO 3 which is easy to desorb, stable sulfate is not formed, and poisoning of sulfur species to active sites is reduced. Meanwhile, the stable existence of the oxygen defect can inhibit the dissociation adsorption of water molecules on the surface of the carrier, reduce the generation of hydroxyl, avoid the phase change of the carrier under the hydrothermal condition, and maintain the structural integrity of the carrier, thereby reducing the poisoning of water on the catalyst. In addition, the invention also constructs a Mo-Nb system, wherein MoO 3 provides acid sites and Nb 2O5 enhances electron transfer, and through double synergy of acid site activation and electron transfer, the comprehensive optimization of CO oxidation reaction kinetics is realized, and meanwhile, the catalyst is endowed with excellent anti-middle toxicity, thermal stability and wide temperature range adaptability.
3. The invention creatively combines supercritical deposition and gradient calcination technologies to realize high dispersion load of active components, thereby enabling the active components and the carrier to form more interface contact points and more 'metal-oxide interface' active sites, enhancing interface coordination of CO oxidation reaction and improving reaction activity of the catalyst.
Detailed Description
In order to make the technical solution of the present invention better understood by those skilled in the art, the technical solution of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention.
Example 1
The anti-aging high-activity CO oxidation catalyst comprises, by mass, 1% of iridium-ruthenium alloy active components (the mass ratio of iridium to ruthenium is 1:1), 85% of tantalum-doped zirconia carriers (the molar ratio of zirconium to tantalum is 9:1) and 14% of composite auxiliary agents. Wherein the composite auxiliary agent is a composite oxide of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is 1:1.
The preparation method of the anti-aging high-activity CO oxidation catalyst comprises the following steps:
s1, preparing a tantalum-doped zirconia carrier by a sol-gel combustion synthesis method, which comprises the following steps:
(1) Dissolving metal salt, namely dissolving zirconyl nitrate and TaCl 5 with the molar ratio of 9:1 into deionized water, stirring to be transparent, adding a combustion agent glycine and citric acid with the mass ratio of 1:2 into the solution, continuously stirring for 30min, regulating the pH value of the solution to 3 by using dilute nitric acid, and promoting the complexing reaction to form uniform sol, wherein the molar ratio of the combustion agent to the total mole number of Zr 4+、Ta5+ is 1.5:1;
(2) Gelling and drying, namely placing the solution in a water bath at 90 ℃, continuously stirring and evaporating to be in a viscous gel state, transferring the gel into an oven, and drying for 12 hours at 100 ℃ to obtain a porous xerogel precursor;
(3) The porous xerogel precursor is ground into powder, uniformity is ensured, the powder is placed in a refractory crucible, and the temperature is raised to 250 ℃ in a muffle furnace at 5 ℃ per min, so as to trigger self-propagating combustion reaction;
(4) High-temperature calcination, namely continuously heating to 600 ℃, and preserving heat for 4 hours to completely decompose organic matters to obtain tantalum doped zirconia crystals;
(5) And cooling and grinding, namely naturally cooling to room temperature, and grinding again to obtain the tantalum-doped zirconia carrier.
S2, pretreatment of the carrier, namely calcining the tantalum-doped zirconia carrier by adopting a gradient calcining method, firstly raising the temperature to 400 ℃ at the rate of 5 ℃ per minute, preserving the heat for 1h, and then raising the temperature to 600 ℃ at the rate of 3 ℃ per minute, and preserving the heat for 2h.
S3, impregnating the composite auxiliary agent, wherein the first impregnating load MoO 3 comprises the following steps of:
(1) Preparing a solution, namely preparing an ammonium molybdate precursor solution with the concentration of 0.1mol/L by using deionized water, adding ammonium tartrate according to the molar ratio of the ammonium tartrate to Mo of 1:1, stirring until the ammonium tartrate is completely dissolved, adjusting the pH value of the solution to 4 by using dilute nitric acid, and inhibiting MoO 3 from rapidly hydrolyzing;
(2) The method comprises the steps of (1) carrying out equal volume impregnation, namely dropwise adding a precursor solution into a tantalum-doped zirconia carrier until the pore volume is saturated;
(3) Standing and aging, namely standing for 12 hours at room temperature in a closed environment to promote uniform adsorption of the Mo complex;
(4) Drying and roasting at 60 deg.c for 12 hr, slow water removal, and roasting in a muffle furnace at 500 deg.c for 4 hr at 3 deg.c/min to form MoO 3 crystal phase;
The secondary impregnation load Nb 2O5 includes the steps of:
1) Preparing an oxalic acid solution into an ammonium niobium oxalate precursor solution with the concentration of 0.05 mol/L;
2) Ultrasonic assisted impregnation, namely immersing a tantalum doped zirconia carrier loaded with MoO 3 precursor into niobium oxalate precursor solution, and immersing the tantalum doped zirconia carrier in a40 kHz ultrasonic tank for 60min;
3) Microwave intensified drying, namely drying in a microwave pulse mode, wherein the drying is performed for 30s on and 15s off, and the power is 300W until the drying is completed;
4) And (3) decomposing and crystallizing, namely presintering for 3 hours at 200 ℃, decomposing organic matters, and then heating to 550 ℃ and calcining for 3 hours to form Nb 2O5.
S4, loading an active component, namely loading an iridium ruthenium alloy active component on a tantalum doped zirconia carrier impregnated with a composite additive by a supercritical CO 2 fluid deposition method to obtain the anti-aging high-activity CO oxidation catalyst, wherein the method specifically comprises the following steps:
(1) Preparing iridium ruthenium alloy precursor solution, namely preparing iridium acetylacetonate and ruthenium acetylacetonate solution by methanol, wherein the methanol accounts for 5vol.%, and the solution is dissolved in an ultrasonic-assisted manner (40 kHz and 30 min) until the solution is clear and has no precipitate, filtering the solution by a 0.22 mu m organic filter membrane, and removing undissolved impurities;
(2) Pre-activating, namely treating the tantalum doped zirconia carrier loaded with the composite additive for 2 hours at the temperature of 250 ℃ in H 2/N2(5vol.％H2) atmosphere to enhance the activity of surface hydroxyl;
(3) Placing the carrier in a reaction kettle under the conditions of 40 ℃ and 15MPa and CO 2 flow rate of 0.5L/min, introducing pure CO 2 to a supercritical state, and maintaining for 30min to remove air;
(4) Injecting a precursor, namely injecting an iridium-ruthenium alloy precursor solution into a reaction kettle through a high-pressure pump to ensure that CO 2 and the precursor are fully mixed;
(5) Dynamic impregnation, namely starting magnetic stirring (500 rpm), and maintaining supercritical conditions for 4 hours to enable the precursor to be uniformly adsorbed on the carrier pores;
(6) Decompression deposition, namely releasing pressure (the speed is 0.2 MPa/min), gradually gasifying CO 2, and directionally depositing a precursor on the surface of a carrier;
(7) Hydrogen reduction, namely introducing H 2/Ar mixed gas (H 2 accounts for 5 vol%) into a tubular furnace, heating to 300 ℃ at 2 ℃ per min, preserving heat for 3 hours to reduce Ir 3+、Ru3+ into a metal state, further heating to 550 ℃, preserving heat for 1 hour, and promoting alloying;
(8) In situ alloying verification
XRD analysis is carried out to detect whether characteristic peaks (such as face-centered cubic phase, 2 theta apprxeq 40.5 degrees and 47.2 degrees) of the Ir-Ru alloy appear.
TEM-EDS surface scanning is carried out to confirm the distribution overlapping degree of Ir and Ru elements (the correlation coefficient is required to be more than 0.9).
The anti-aging high-activity CO oxidation catalyst prepared in the embodiment is used for small test for simulating the components of steel sintering flue gas, the initial activity test condition is 4000ppm CO+15% O 2, the airspeed is 100000h -1, the poisoning-resistance aging test condition is 4000ppm CO+15% O 2+2000ppm SO2+1000ppm NO+50ppm NH3+15％H2 O, and the CO conversion rate under the initial activity test condition at 270 ℃ is 98.2%. After 24 hours of aging under the above poisoning-resistant aging test conditions, the CO conversion was measured to be 93.6%.
Example 2
The anti-aging high-activity CO oxidation catalyst comprises, by mass, 0.5% of iridium-ruthenium alloy active components (the mass ratio of iridium to ruthenium is 1:3), 88% of tantalum-doped zirconia carriers (the molar ratio of zirconium to tantalum is 15:1), and 11.5% of composite auxiliary agents. Wherein the composite auxiliary agent is a composite oxide of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is 2:1.
The preparation method of the anti-aging high-activity CO oxidation catalyst comprises the following steps:
s1, preparing a tantalum-doped zirconia carrier by a sol-gel combustion synthesis method, which comprises the following steps:
(1) Dissolving metal salt, namely dissolving zirconyl nitrate and TaCl 5 with the molar ratio of 15:1 into deionized water, stirring to be transparent, adding a combustion agent glycine and citric acid with the mass ratio of 1:3 into the solution, continuously stirring for 30min, regulating the pH value of the solution to 4 by using dilute nitric acid, and promoting the complexing reaction to form uniform sol, wherein the molar ratio of the combustion agent to the total mole number of Zr 4+、Ta5+ is 2:1;
(2) Gelling and drying, namely placing the solution in a water bath at 90 ℃, continuously stirring and evaporating to be in a viscous gel state, transferring the gel into an oven, and drying for 12 hours at 110 ℃ to obtain a porous xerogel precursor;
(3) The porous xerogel precursor is ground into powder, uniformity is ensured, the powder is placed in a refractory crucible, and the temperature is raised to 300 ℃ in a muffle furnace at 5 ℃ per min, so as to trigger self-propagating combustion reaction;
(4) High-temperature calcination, namely continuously heating to 700 ℃, and preserving heat for 3 hours to completely decompose organic matters to obtain tantalum doped zirconia crystals;
(5) And cooling and grinding, namely naturally cooling to room temperature, and grinding again to obtain the tantalum-doped zirconia carrier.
S2, pretreatment of the carrier, namely calcining the tantalum-doped zirconia carrier by adopting a gradient calcining method, firstly raising the temperature to 450 ℃ at the rate of 8 ℃ per minute, preserving the heat for 2 hours, and then raising the temperature to 600 ℃ at the rate of 5 ℃ per minute, and preserving the heat for 3 hours.
S3, impregnating the composite auxiliary agent, wherein the first impregnating load MoO 3 comprises the following steps of:
(1) Preparing a solution, namely preparing an ammonium molybdate precursor solution with the concentration of 0.3mol/L by using deionized water, adding ammonium tartrate according to the molar ratio of the ammonium tartrate to Mo of 2:1, stirring until the ammonium tartrate is completely dissolved, adjusting the pH value of the solution to 5 by using dilute nitric acid, and inhibiting MoO 3 from rapidly hydrolyzing;
(2) The method comprises the steps of (1) carrying out equal volume impregnation, namely dropwise adding a precursor solution into a tantalum-doped zirconia carrier until the pore volume is saturated;
(3) Standing and aging, namely standing for 10 hours at room temperature in a closed environment to promote uniform adsorption of the Mo complex;
(4) Drying and roasting at 70deg.C for 12 hr, slowly removing water, calcining at 450deg.C in muffle furnace for 5 hr, and heating at 3 deg.C/min to form MoO 3 crystal phase;
The secondary impregnation load Nb 2O5 includes the steps of:
1) Preparing an oxalic acid solution into an ammonium niobium oxalate precursor solution with the concentration of 0.1 mol/L;
2) Ultrasonic assisted impregnation, namely immersing a tantalum doped zirconia carrier loaded with MoO 3 precursor into niobium oxalate precursor solution, and immersing the tantalum doped zirconia carrier in a 50kHz ultrasonic tank for 60min;
3) Microwave intensified drying, namely drying in a microwave pulse mode, wherein the drying is performed for 40s, the drying is stopped for 20s, and the power is 500W until the drying is completed;
4) Decomposing and crystallizing, namely presintering for 2 hours at 250 ℃, decomposing organic matters, and then heating to 550 ℃ for calcining for 3 hours to form Nb 2O5.
S4, loading an active component, namely loading an iridium ruthenium alloy active component on a tantalum doped zirconia carrier impregnated with a composite additive by a supercritical CO 2 fluid deposition method to obtain the anti-aging high-activity CO oxidation catalyst, wherein the method specifically comprises the following steps:
(1) Preparing iridium ruthenium alloy precursor solution, namely preparing iridium acetylacetonate and ruthenium acetylacetonate solution by methanol, wherein the methanol accounts for 8vol percent, and dissolving the solution in an ultrasonic-assisted manner (40 kHz and 30 min) until the solution is clear and has no precipitate, filtering the solution by an organic filter membrane with the thickness of 0.25 mu m, and removing undissolved impurities;
(2) Pre-activating, namely treating the tantalum doped zirconia carrier loaded with the composite additive for 10 hours at 300 ℃ in H 2/N2(5vol.％H2) atmosphere to enhance the activity of surface hydroxyl;
(3) Placing the carrier in a reaction kettle under the conditions of 60 ℃ and 13MPa, and CO 2 flow rate of 2L/min, introducing pure CO 2 to a supercritical state, and maintaining for 30min to remove air;
(4) Injecting a precursor, namely injecting an iridium-ruthenium alloy precursor solution into a reaction kettle through a high-pressure pump to ensure that CO 2 and the precursor are fully mixed;
(5) Dynamic impregnation, namely starting magnetic stirring (600 rpm), and maintaining supercritical conditions for 3 hours to enable the precursor to be uniformly adsorbed on the carrier pores;
(6) Decompression deposition, namely releasing pressure (the speed is 0.3 MPa/min), gradually gasifying CO 2, and directionally depositing a precursor on the surface of a carrier;
(7) Hydrogen reduction, namely introducing H 2/Ar mixed gas (H 2 accounts for 8 vol%) into a tubular furnace, heating to 400 ℃ at 2 ℃ per min, preserving heat for 2 hours to reduce Ir 3+、Ru3+ into a metal state, further heating to 550 ℃, preserving heat for 2 hours, and promoting alloying;
(8) In situ alloying verification
XRD analysis is carried out to detect whether characteristic peaks (such as face-centered cubic phase, 2 theta apprxeq 40.5 degrees and 47.2 degrees) of the Ir-Ru alloy appear.
TEM-EDS surface scanning is carried out to confirm the distribution overlapping degree of Ir and Ru elements (the correlation coefficient is required to be more than 0.9).
The anti-aging high-activity CO oxidation catalyst prepared in the example was used for small-scale detection of simulated steel sintering flue gas components, and under the same test conditions as in example 1, the CO conversion rate under the initial activity test condition at 270 ℃ was measured to be 97.8%, and the CO conversion rate after aging was measured to be 92.6%.
Example 3
The anti-aging high-activity CO oxidation catalyst comprises, by mass, 1.5% of iridium-ruthenium alloy active components (the mass ratio of iridium to ruthenium is 1:5), 82% of tantalum-doped zirconia carriers (the molar ratio of zirconium to tantalum is 19:1), and 16.5% of composite auxiliary agents. Wherein the composite additive is a composite oxide of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is 3:1.
The preparation method of the anti-aging high-activity CO oxidation catalyst comprises the following steps:
s1, preparing a tantalum-doped zirconia carrier by a sol-gel combustion synthesis method, which comprises the following steps:
(1) Dissolving metal salt, namely dissolving zirconyl nitrate and TaCl 5 with the molar ratio of 19:1 into deionized water, stirring to be transparent, adding a combustion agent glycine and citric acid with the mass ratio of 1:2 into the solution, continuously stirring for 30min, regulating the pH value of the solution to 3 by using dilute nitric acid, and promoting the complexing reaction to form uniform sol, wherein the molar ratio of the combustion agent to the total mole number of Zr 4+、Ta5+ is 1.8:1;
(2) Gelling and drying, namely placing the solution in a water bath at 90 ℃, continuously stirring and evaporating to be in a viscous gel state, transferring the gel into an oven, and drying for 12 hours at 110 ℃ to obtain a porous xerogel precursor;
(3) The porous xerogel precursor is ground into powder, uniformity is ensured, the powder is placed in a refractory crucible, and the temperature is raised to 300 ℃ in a muffle furnace at 5 ℃ per min, so as to trigger self-propagating combustion reaction;
(4) High-temperature calcination, namely continuously heating to 800 ℃, and preserving heat for 2 hours to completely decompose organic matters to obtain tantalum-doped zirconia crystals;
(5) And cooling and grinding, namely naturally cooling to room temperature, and grinding again to obtain the tantalum-doped zirconia carrier.
S2, pretreatment of the carrier, namely calcining the tantalum-doped zirconia carrier by adopting a gradient calcining method, firstly raising the temperature to 400 ℃ at the rate of 10 ℃ per minute, preserving the heat for 2 hours, and then raising the temperature to 600 ℃ at the rate of 5 ℃ per minute, and preserving the heat for 3 hours.
S3, impregnating the composite auxiliary agent, wherein the first impregnating load MoO 3 comprises the following steps of:
(1) Preparing a solution, namely preparing an ammonium molybdate precursor solution with the concentration of 0.5mol/L by using deionized water, adding ammonium tartrate according to the molar ratio of the ammonium tartrate to Mo of 2:1, stirring until the ammonium tartrate is completely dissolved, adjusting the pH value of the solution to 5 by using dilute nitric acid, and inhibiting MoO 3 from rapidly hydrolyzing;
(2) The method comprises the steps of (1) carrying out equal volume impregnation, namely dropwise adding a precursor solution into a tantalum-doped zirconia carrier until the pore volume is saturated;
(3) Standing and aging, namely standing for 12 hours at room temperature in a closed environment to promote uniform adsorption of the Mo complex;
(4) Drying and roasting at 80 deg.c for 12 hr, slow water removal, and roasting in a muffle furnace at 500 deg.c for 5 hr at 3 deg.c/min to form MoO 3 crystal phase;
The secondary impregnation load Nb 2O5 includes the steps of:
1) Preparing an oxalic acid solution into an ammonium niobium oxalate precursor solution with the concentration of 0.2 mol/L;
2) Ultrasonic assisted impregnation, namely immersing a tantalum doped zirconia carrier loaded with MoO 3 precursor into niobium oxalate precursor solution, and immersing the tantalum doped zirconia carrier in a 50kHz ultrasonic tank for 60min;
3) Microwave intensified drying, namely drying in a microwave pulse mode, wherein the power is 600W after 40s is started and 15s is stopped, and the drying is completed;
4) Decomposing and crystallizing, namely presintering for 3 hours at 250 ℃, decomposing organic matters, and then heating to 550 ℃ for calcining for 4 hours to form Nb 2O5.
S4, loading an active component, namely loading an iridium ruthenium alloy active component on a tantalum doped zirconia carrier impregnated with a composite additive by a supercritical CO 2 fluid deposition method to obtain the anti-aging high-activity CO oxidation catalyst, wherein the method specifically comprises the following steps:
(1) Preparing iridium ruthenium alloy precursor solution, namely preparing iridium acetylacetonate and ruthenium acetylacetonate solution by methanol, wherein the methanol accounts for 10vol.%, and the solution is dissolved in an ultrasonic-assisted manner (40 kHz and 30 min) until the solution is clear and has no precipitate, filtering the solution by a 0.25 mu m organic filter membrane, and removing undissolved impurities;
(2) Pre-activating, namely treating the tantalum doped zirconia carrier loaded with the composite additive for 22 hours at 350 ℃ in H 2/N2(5vol.％H2) atmosphere to enhance the activity of surface hydroxyl;
(3) Placing the carrier in a reaction kettle under the conditions of 60 ℃ and 12MPa and CO 2 flow rate of 2L/min, introducing pure CO 2 to a supercritical state, and maintaining for 30min to remove air;
(4) Injecting a precursor, namely injecting an iridium-ruthenium alloy precursor solution into a reaction kettle through a high-pressure pump to ensure that CO 2 and the precursor are fully mixed;
(5) Dynamic impregnation, namely starting magnetic stirring (800 rpm), and maintaining supercritical conditions for 4 hours to enable the precursor to be uniformly adsorbed on the carrier pores;
(6) Decompression deposition, namely releasing pressure (the speed is 0.5 MPa/min), gradually gasifying CO 2, and directionally depositing a precursor on the surface of a carrier;
(7) Hydrogen reduction, namely introducing H 2/Ar mixed gas (H 2 accounts for 10 vol%) into a tubular furnace, heating to 400 ℃ at 2 ℃ per min, preserving heat for 3 hours to reduce Ir 3+、Ru3+ into a metal state, further heating to 550 ℃, preserving heat for 2 hours, and promoting alloying;
(8) In situ alloying verification
XRD analysis is carried out to detect whether characteristic peaks (such as face-centered cubic phase, 2 theta apprxeq 40.5 degrees and 47.2 degrees) of the Ir-Ru alloy appear.
TEM-EDS surface scanning is carried out to confirm the distribution overlapping degree of Ir and Ru elements (the correlation coefficient is required to be more than 0.9).
The anti-aging high-activity CO oxidation catalyst prepared in the example was used for small-scale detection of simulated steel sintering flue gas components, and the CO conversion rate under the 280 ℃ initial activity test condition was measured to be 98.5% and the CO conversion rate after aging was measured to be 95.6% under the same test condition as in example 1.
Example 4
The anti-aging high-activity CO oxidation catalyst comprises, by mass, 0.8% of iridium-ruthenium alloy active components (the mass ratio of iridium to ruthenium is 1:3), 87% of tantalum-doped zirconia carriers (the molar ratio of zirconium to tantalum is 16:1) and 12.2% of composite assistants. Wherein the composite auxiliary agent is a composite oxide of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is 2:1.
The preparation method of the anti-aging high-activity CO oxidation catalyst comprises the following steps:
s1, preparing a tantalum-doped zirconia carrier by a sol-gel combustion synthesis method, which comprises the following steps:
(1) Dissolving metal salt, namely dissolving zirconyl nitrate and TaCl 5 with the molar ratio of 16:1 into deionized water, stirring to be transparent, adding a combustion agent glycine and citric acid with the mass ratio of 1:2 into the solution, continuously stirring for 30min, regulating the pH value of the solution to 4 by using dilute nitric acid, and promoting the complexing reaction to form uniform sol, wherein the molar ratio of the combustion agent to the total mole number of Zr 4+、Ta5+ is 2:1;
(2) Gelling and drying, namely placing the solution in a water bath at 80 ℃, continuously stirring and evaporating to be in a viscous gel state, transferring the gel into an oven, and drying for 11 hours at 105 ℃ to obtain a porous xerogel precursor;
(3) The porous xerogel precursor is ground into powder, uniformity is ensured, the powder is placed in a refractory crucible, and the temperature is increased to 300 ℃ in a muffle furnace at 10 ℃ per min, so as to trigger self-propagating combustion reaction;
(4) High-temperature calcination, namely continuously heating to 700 ℃, and preserving heat for 3 hours to completely decompose organic matters to obtain tantalum doped zirconia crystals;
(5) And cooling and grinding, namely naturally cooling to room temperature, and grinding again to obtain the tantalum-doped zirconia carrier.
S2, pretreatment of the carrier, namely calcining the tantalum-doped zirconia carrier by adopting a gradient calcining method, firstly raising the temperature to 450 ℃ at the rate of 10 ℃ per minute, preserving the heat for 1h, and then raising the temperature to 550 ℃ at the rate of 3 ℃ per minute, and preserving the heat for 3h.
S3, impregnating the composite auxiliary agent, wherein the first impregnating load MoO 3 comprises the following steps of:
(1) Preparing a solution, namely preparing an ammonium molybdate precursor solution with the concentration of 0.5mol/L by using deionized water, adding ammonium tartrate according to the molar ratio of the ammonium tartrate to Mo of 2:1, stirring until the ammonium tartrate is completely dissolved, adjusting the pH value of the solution to 3 by using dilute nitric acid, and inhibiting MoO 3 from rapidly hydrolyzing;
(2) The method comprises the steps of (1) carrying out equal volume impregnation, namely dropwise adding a precursor solution into a tantalum-doped zirconia carrier until the pore volume is saturated;
(3) Standing and aging, namely standing for 6 hours at room temperature in a closed environment to promote uniform adsorption of the Mo complex;
(4) Drying and roasting at 80deg.C for 12 hr, slowly removing water, calcining at 400deg.C in muffle furnace for 4.5 hr at heating rate of 2deg.C/min to form MoO 3 crystal phase;
The secondary impregnation load Nb 2O5 includes the steps of:
1) Preparing an oxalic acid solution into an ammonium niobium oxalate precursor solution with the concentration of 0.05 mol/L;
2) Ultrasonic assisted impregnation, namely immersing a tantalum doped zirconia carrier loaded with MoO 3 precursor into niobium oxalate precursor solution, and immersing the tantalum doped zirconia carrier in a 45kHz ultrasonic tank for 30min;
3) Microwave intensified drying, namely drying in a microwave pulse mode, wherein the drying is performed for 30s, the drying is stopped for 20s, and the power is 600W until the drying is completed;
4) Decomposing and crystallizing, namely presintering for 3 hours at 250 ℃, decomposing organic matters, and then heating to 450 ℃ for calcining for 4 hours to form Nb 2O5.
S4, loading an active component, namely loading an iridium ruthenium alloy active component on a tantalum doped zirconia carrier impregnated with a composite additive by a supercritical CO 2 fluid deposition method to obtain the anti-aging high-activity CO oxidation catalyst, wherein the method specifically comprises the following steps:
(1) Preparing iridium ruthenium alloy precursor solution, namely preparing iridium acetylacetonate and ruthenium acetylacetonate solution by methanol, wherein the methanol accounts for 10vol.%, and the solution is dissolved in an ultrasonic-assisted manner (40 kHz and 30 min) until the solution is clear and has no precipitate, filtering the solution by a 0.25 mu m organic filter membrane, and removing undissolved impurities;
(2) Pre-activating, namely treating the tantalum doped zirconia carrier loaded with the composite additive for 20 hours at 350 ℃ in H 2/N2(5vol.％H2) atmosphere to enhance the activity of surface hydroxyl;
(3) Placing the carrier in a reaction kettle under the conditions of 50 ℃ and 10MPa and CO 2 flow rate of 2L/min, introducing pure CO 2 to a supercritical state, and maintaining for 30min to remove air;
(4) Injecting a precursor, namely injecting an iridium-ruthenium alloy precursor solution into a reaction kettle through a high-pressure pump to ensure that CO 2 and the precursor are fully mixed;
(5) Dynamic impregnation, namely starting magnetic stirring (800 rpm), and maintaining supercritical conditions for 2 hours to enable the precursor to be uniformly adsorbed on the carrier pores;
(6) Decompression deposition, namely releasing pressure (the speed is 0.4 MPa/min), gradually gasifying CO 2, and directionally depositing a precursor on the surface of a carrier;
(7) Hydrogen reduction, namely introducing H 2/Ar mixed gas (H 2 accounts for 10 vol%) into a tubular furnace, heating to 350 ℃ at 2 ℃ per min, preserving heat for 3 hours to reduce Ir 3+、Ru3+ into a metal state, further heating to 450 ℃, preserving heat for 2 hours, and promoting alloying;
(8) In situ alloying verification
XRD analysis is carried out to detect whether characteristic peaks (such as face-centered cubic phase, 2 theta apprxeq 40.5 degrees and 47.2 degrees) of the Ir-Ru alloy appear.
TEM-EDS surface scanning is carried out to confirm the distribution overlapping degree of Ir and Ru elements (the correlation coefficient is required to be more than 0.9).
The anti-aging high-activity CO oxidation catalyst prepared in the example was used for small-scale detection of simulated steel sintering flue gas components, and the CO conversion rate under the 280 ℃ initial activity test condition was measured to be 98% and the CO conversion rate after aging was measured to be 94.8% under the same test condition as in example 1.
Example 5
The anti-aging high-activity CO oxidation catalyst comprises, by mass, 1.2% of iridium-ruthenium alloy active components (the mass ratio of iridium to ruthenium is 1:3), 84% of tantalum-doped zirconia carriers (the molar ratio of zirconium to tantalum is 9:1), and 14.8% of composite auxiliary agents. Wherein the composite auxiliary agent is a composite oxide of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is 2:1.
The preparation method of the anti-aging high-activity CO oxidation catalyst comprises the following steps:
s1, preparing a tantalum-doped zirconia carrier by a sol-gel combustion synthesis method, which comprises the following steps:
(1) Dissolving metal salt, namely dissolving zirconyl nitrate and TaCl 5 with the molar ratio of 9:1 into deionized water, stirring to be transparent, adding a combustion agent glycine and citric acid with the mass ratio of 1:2 into the solution, continuously stirring for 30min, regulating the pH value of the solution to 3 by using dilute nitric acid, and promoting the complexing reaction to form uniform sol, wherein the molar ratio of the combustion agent to the total mole number of Zr 4+、Ta5+ is 1.5:1;
(2) Gelling and drying, namely placing the solution in a water bath at 85 ℃, continuously stirring and evaporating to be in a viscous gel state, transferring the gel into an oven, and drying for 10 hours at 110 ℃ to obtain a porous xerogel precursor;
(3) The porous xerogel precursor is ground into powder, uniformity is ensured, the powder is placed in a refractory crucible, and the temperature is raised to 300 ℃ in a muffle furnace at 5 ℃ per min, so as to trigger self-propagating combustion reaction;
(4) High-temperature calcination, namely continuously heating to 800 ℃, and preserving heat for 3 hours to completely decompose organic matters to obtain tantalum-doped zirconia crystals;
(5) And cooling and grinding, namely naturally cooling to room temperature, and grinding again to obtain the tantalum-doped zirconia carrier.
S2, pretreatment of the carrier, namely calcining the tantalum-doped zirconia carrier by adopting a gradient calcining method, firstly raising the temperature to 400 ℃ at the rate of 5 ℃ per minute, preserving the heat for 1h, and then raising the temperature to 550 ℃ at the rate of 4 ℃ per minute, and preserving the heat for 2h.
S3, impregnating the composite auxiliary agent, wherein the first impregnating load MoO 3 comprises the following steps of:
(1) Preparing a solution, namely preparing an ammonium molybdate precursor solution with the concentration of 0.5mol/L by using deionized water, adding ammonium tartrate according to the molar ratio of the ammonium tartrate to Mo of 2:1, stirring until the ammonium tartrate is completely dissolved, adjusting the pH value of the solution to 5 by using dilute nitric acid, and inhibiting MoO 3 from rapidly hydrolyzing;
(2) The method comprises the steps of (1) carrying out equal volume impregnation, namely dropwise adding a precursor solution into a tantalum-doped zirconia carrier until the pore volume is saturated;
(3) Standing and aging, namely standing for 6 hours at room temperature in a closed environment to promote uniform adsorption of the Mo complex;
(4) Drying and roasting at 80deg.C for 12 hr, slowly removing water, calcining at 400deg.C in muffle furnace for 4 hr at a heating rate of 2deg.C/min to form MoO 3 crystal phase;
The secondary impregnation load Nb 2O5 includes the steps of:
1) Preparing an oxalic acid solution into an ammonium niobium oxalate precursor solution with the concentration of 0.2 mol/L;
2) Ultrasonic assisted impregnation, namely immersing a tantalum doped zirconia carrier loaded with MoO 3 precursor into niobium oxalate precursor solution, and immersing the tantalum doped zirconia carrier in a 50kHz ultrasonic tank for 50min;
3) Microwave intensified drying, namely drying in a microwave pulse mode, wherein the drying is performed for 40s, the drying is stopped for 20s, and the power is 500W until the drying is completed;
4) And (3) decomposing and crystallizing, namely presintering for 3 hours at 220 ℃, decomposing organic matters, and then heating to 500 ℃ and calcining for 4 hours to form Nb 2O5.
S4, loading an active component, namely loading an iridium ruthenium alloy active component on a tantalum doped zirconia carrier impregnated with a composite additive by a supercritical CO 2 fluid deposition method to obtain the anti-aging high-activity CO oxidation catalyst, wherein the method specifically comprises the following steps:
(1) Preparing iridium ruthenium alloy precursor solution, namely preparing iridium acetylacetonate and ruthenium acetylacetonate solution by methanol, wherein the methanol accounts for 10vol.%, and the solution is dissolved in an ultrasonic-assisted manner (40 kHz and 30 min) until the solution is clear and has no precipitate, filtering the solution by a 0.24 mu m organic filter membrane, and removing undissolved impurities;
(2) Pre-activating, namely treating the tantalum doped zirconia carrier loaded with the composite additive for 1H at 350 ℃ in H 2/N2(5vol.％H2) atmosphere to enhance the activity of surface hydroxyl;
(3) Placing the carrier in a reaction kettle under the conditions of 60 ℃ and 10MPa and CO 2 flow rate of 1L/min, introducing pure CO 2 to a supercritical state, and maintaining for 30min to remove air;
(4) Injecting a precursor, namely injecting an iridium-ruthenium alloy precursor solution into a reaction kettle through a high-pressure pump to ensure that CO 2 and the precursor are fully mixed;
(5) Dynamic impregnation, namely starting magnetic stirring (800 rpm), and maintaining supercritical conditions for 4 hours to enable the precursor to be uniformly adsorbed on the carrier pores;
(6) Decompression deposition, namely releasing pressure (the speed is 0.5 MPa/min), gradually gasifying CO 2, and directionally depositing a precursor on the surface of a carrier;
(7) Hydrogen reduction, namely introducing H 2/Ar mixed gas (H 2 accounts for 10 vol%) into a tubular furnace, heating to 400 ℃ at 2 ℃ per min, preserving heat for 3 hours to reduce Ir 3+、Ru3+ into a metal state, further heating to 500 ℃, preserving heat for 2 hours, and promoting alloying;
(8) In situ alloying verification
XRD analysis is carried out to detect whether characteristic peaks (such as face-centered cubic phase, 2 theta apprxeq 40.5 degrees and 47.2 degrees) of the Ir-Ru alloy appear.
TEM-EDS surface scanning is carried out to confirm the distribution overlapping degree of Ir and Ru elements (the correlation coefficient is required to be more than 0.9).
The anti-aging high-activity CO oxidation catalyst prepared in the example was used for small-scale detection of simulated steel sintering flue gas components, and the CO conversion rate under the 280 ℃ initial activity test condition was measured to be 98.3% and the CO conversion rate after aging was measured to be 94.3% under the same test condition as in example 1.
Comparative example 1
The difference from example 1 is that the mass ratio of MoO 3 to Nb 2O5 in the composite additive is 5:1.
The CO oxidation catalyst prepared in comparative example 1 was used for pilot test for simulating the composition of steel sintering flue gas, and the CO conversion under the initial activity test condition of 270 ℃ was measured to be 83.8% under the test condition same as that of example 1, and the CO conversion after aging was measured to be 70.6%. This is because excessive Mo addition results in excessive acidic sites and excessive strength, which leads to excessive CO adsorption, NH 3 enrichment, increased side reactions, and eventually reduced catalytic efficiency and poisoning resistance.
Comparative example 2
The difference from example 1 is that the mass ratio of MoO 3 to Nb 2O5 in the composite additive is 0.8:1.
The CO oxidation catalyst prepared in comparative example 2 was used for a pilot test to simulate the composition of steel sintering flue gas, and its CO conversion under the initial activity test conditions of 270 ℃ was measured to be 76.9% under the same test conditions as in example 1, and the CO conversion after aging was measured to be 65.7%. This is because too small a Mo content results in too small an acidic site of the catalyst and weak adsorption ability to CO is weakened, and thus the activity of the catalyst is lowered.
Comparative example 3
The difference from example 1 is that pure iridium is used as active ingredient.
The CO oxidation catalyst prepared in comparative example 3 was used for a pilot test to simulate the composition of steel sintering flue gas, and its CO conversion under the initial activity test conditions of 270 ℃ was measured to be 82.5% and the CO conversion after aging was measured to be 71.7% under the same test conditions as in example 1.
Comparative example 4
The difference from example 1 is that the active component is pure ruthenium.
The CO oxidation catalyst prepared in comparative example 4 was used for pilot test to simulate the composition of steel sintering flue gas, and its CO conversion was measured to be 75.8% under the initial activity test condition of 270 ℃ under the same test condition as in example 1, and the CO conversion after aging was measured to be 62.3%.
The catalyst of comparative examples 3-4 has reduced performance compared to example 1 because the core of the electron synergy of Ir and Ru is to optimize the electron state of the active sites, weaken CO adsorption, avoid active site blocking, promote O 2 activation, provide sufficient active oxygen species, reduce the reaction energy barrier, accelerate co→co 2 conversion, enhance stability, resist poisons and sintering by charge transfer, band modulation and interfacial coupling. Thus, the absence of Ru in comparative example 3 and Ir in comparative example 4 results in a reduced electron synergism between the active species, and thus a reduced activity and poisoning resistance of the catalyst.
Comparative example 5
The difference from example 1 is that a Pt/Pd active component (mass ratio of Pt to Pd is 1:3) is used instead of the iridium ruthenium alloy active component.
The CO oxidation catalyst prepared in comparative example 5 was used for a pilot test to simulate the composition of steel sintering flue gas, and its CO conversion under the initial activity test conditions of 270 ℃ was measured to be 82.7% under the same test conditions as in example 1, and the CO conversion after aging was measured to be 69.6%. The Ir/Ru oxide can reduce the reaction energy barrier through a lattice oxygen participation mechanism, pt/Pd depends on a traditional adsorbate mechanism, SO that the reaction energy barrier is high, the reaction activity is low, the surface of the Ir/Ru is more inert, pt/Pd is easily poisoned by small molecules such as NO\SO 2, the surface active site is occupied, the binding energy of the Ir/Ru on adsorbate is weak, and the poisoning resistance is strong.
Comparative example 6
The difference from example 1 is that the support is a Ce doped zirconia support.
The CO oxidation catalyst prepared in comparative example 6 was used for pilot test to simulate the composition of steel sintering flue gas, and its CO conversion was measured to be 73.2% under the initial activity test condition of 270 ℃ under the same test condition as in example 1, and the CO conversion after aging was measured to be 63.6%.
The invention develops a tantalum-doped zirconia carrier, and stable oxygen defect sites are generated through Ta 5+ induction, SO that the oxygen activating capacity of a catalyst is enhanced, SO 2 is promoted to be oxidized into SO 3 which is easy to desorb, stable sulfate is not formed, and poisoning of sulfur species to active sites is reduced. The oxygen storage and release capacity of CeO 2 depends on Ce 3+/Ce4+ circulation, active oxygen is enriched on the surface, and stable Ce 2(SO4)3 is easily generated by combining with SO 3, SO that the catalyst is poisoned.
Comparative example 7
The difference from example 1 is that no MoO 3 was added to the compounding chemicals.
The CO oxidation catalyst prepared in comparative example 7 was used for a pilot test to simulate the composition of steel sintering flue gas, and its CO conversion under the initial activity test conditions of 270 ℃ was measured to be 75.9% under the same test conditions as in example 1, and the CO conversion after aging was measured to be 60.9%. This is because the acid site of the catalyst is reduced without adding MoO 3, and its ability to adsorb and activate CO is reduced, resulting in a decrease in the activity and poisoning resistance of the catalyst.
Comparative example 8
The difference from example 1 is that no Nb 2O5 was added to the compounding aid.
The CO oxidation catalyst prepared in comparative example 8 was used for a pilot test to simulate the composition of steel sintering flue gas, and its CO conversion under the initial activity test conditions of 270 ℃ was measured to be 80.5% under the same test conditions as in example 1, and the CO conversion after aging was measured to be 68.7%. This is because the synergistic effect of electrons is reduced, resulting in a decrease in catalyst activity and poisoning resistance.
Claims (9)
1. The anti-aging high-activity CO oxidation catalyst is characterized by comprising, by mass, 0.1-2% of iridium-ruthenium alloy active components, 80-90% of tantalum-doped zirconia carriers and 10-20% of composite assistants, wherein the composite assistants are composite oxides of MoO 3 and Nb 2O5, and the mass ratio of MoO 3 to Nb 2O5 is (1-3): 1.
2. The anti-aging high-activity CO oxidation catalyst according to claim 1, wherein the mass ratio of iridium to ruthenium in the iridium-ruthenium alloy active component is 1 (1-5).
3. The anti-aging, high activity CO oxidation catalyst according to claim 1, wherein the molar ratio of zirconium to tantalum in the tantalum doped zirconia support is (9-19): 1.
4. A method for preparing an anti-aging high activity CO oxidation catalyst according to any one of claims 1 to 3, comprising the steps of:
s1, preparing a carrier, namely preparing a tantalum-doped zirconia carrier through a sol-gel combustion synthesis method;
s2, pretreatment of a carrier, namely calcining the tantalum-doped zirconia carrier by adopting a gradient calcining method, firstly raising the temperature to 400-450 ℃ at the rate of 5-10 ℃ per minute, preserving heat for 1-2 hours, then raising the temperature to 550-600 ℃ at the rate of 3-5 ℃ per minute, and preserving heat for 2-3 hours;
S3, impregnating the composite auxiliary agent, namely carrying out primary impregnation on the tantalum-doped zirconia carrier by taking ammonium tartrate as a complexing agent to carry MoO 3, and carrying out secondary impregnation by adopting an ultrasonic auxiliary microwave drying method to carry Nb 2O5 on the tantalum-doped zirconia carrier;
s4, loading the active component, namely loading the iridium ruthenium alloy active component on the tantalum doped zirconia carrier impregnated with the composite additive by adopting a supercritical CO 2 fluid deposition method, and obtaining the anti-aging high-activity CO oxidation catalyst.
5. The method for preparing the anti-aging high-activity CO oxidation catalyst according to claim 4, wherein in step S1, the preparation of the tantalum doped zirconia support by the sol-gel combustion synthesis method comprises the following steps:
(1) Dissolving metal salt, namely dissolving zirconyl nitrate and tantalum pentachloride in deionized water, stirring until the solution is transparent, adding a combustion agent, continuously stirring, and regulating the pH value of the solution to 3-4;
(2) Gelling and drying, namely placing the solution in a water bath at 80-90 ℃, continuously stirring and evaporating to be in a viscous gel state, transferring to an oven and drying to obtain a porous xerogel precursor;
(3) The porous xerogel precursor is ground into powder, the powder is placed in a muffle furnace, the temperature is raised to 250-300 ℃ at 5-10 ℃ per min, and the self-propagating combustion reaction is triggered;
(4) High temperature calcination, namely continuously heating to 600-800 ℃, and preserving heat for 2-4 hours to completely decompose organic matters to obtain tantalum doped zirconia crystals;
(5) And cooling and grinding, namely naturally cooling to room temperature, and grinding again to obtain the tantalum-doped zirconia carrier.
6. The method for preparing an anti-aging high-activity CO oxidation catalyst according to claim 5, wherein in the step (1), the combustion agent is glycine and citric acid in a mass ratio of (2-3), and the molar ratio of the combustion agent to the total mole number of Zr 4+、Ta5+ is (1.5-2): 1.
7. The method for preparing an anti-aging high-activity CO oxidation catalyst according to claim 5, wherein in the step (2), the drying temperature is 100-110 ℃ and the drying time is 10-12 hours.
8. The method for preparing an anti-aging high activity CO oxidation catalyst according to claim 4, wherein in step S3, the first impregnation supporting MoO 3 comprises the steps of:
(1) Preparing solution, namely preparing ammonium molybdate precursor solution with the concentration of 0.1-0.5mol/L by deionized water, adding ammonium tartrate according to the molar ratio of ammonium tartrate to Mo of (1-2): 1, stirring until the ammonium tartrate is completely dissolved, and adjusting the pH value of the solution to 3-5;
(2) The method comprises the steps of (1) carrying out equal volume impregnation, namely dropwise adding a precursor solution into a tantalum-doped zirconia carrier until the pore volume is saturated;
(3) Standing and aging, namely standing for 6-12h at room temperature in a closed environment;
(4) Drying and roasting at 60-80deg.C for 12 hr, calcining at 400-500deg.C in muffle furnace for 4-5 hr at a heating rate of 2-3deg.C/min to form MoO 3 crystal phase;
The secondary impregnation load Nb 2O5 includes the steps of:
1) Preparing an oxalic acid solution into an ammonium niobium oxalate precursor solution with the concentration of 0.05-0.2 mol/L;
2) Ultrasonic assisted impregnation, namely immersing a tantalum doped zirconia carrier loaded with MoO 3 precursor into niobium oxalate precursor solution, and immersing in a 40-50kHz ultrasonic tank for 30-60min;
3) Drying by microwave enhanced drying, namely drying by adopting a microwave pulse mode, starting 30-40s, stopping 15-20s, and enabling the power to be 300-600W until the drying is completed;
4) Decomposing and crystallizing, namely presintering for 2-3 hours at 200-250 ℃, and then heating to 450-550 ℃ for calcining for 3-4 hours.
9. The method for preparing the anti-aging high activity CO oxidation catalyst according to claim 4, wherein in step S4, the supercritical CO 2 fluid deposition method comprises the steps of:
(1) Preparing iridium-ruthenium alloy precursor solution, namely preparing iridium acetylacetonate and ruthenium acetylacetonate solution by using methanol, wherein the methanol accounts for 5-10 vol%;
(2) Pre-activating, namely treating the tantalum doped zirconia carrier loaded with the composite additive for 1-22 hours at the temperature of 250-350 ℃ in the atmosphere of H 2/N2;
(3) Placing the carrier in a reaction kettle under the conditions of 40-60 ℃ and 10-15MPa, and CO 2 flow rate of 0.5-2L/min, introducing pure CO 2 to supercritical state, and maintaining for 30min to remove air;
(4) Injecting a precursor, namely injecting an iridium-ruthenium alloy precursor solution into a reaction kettle to ensure that CO 2 and the precursor are fully mixed;
(5) Dynamic impregnation, namely maintaining supercritical conditions for 2-4 hours under stirring conditions to enable the precursor to be uniformly adsorbed on the carrier pores;
(6) Decompression deposition, namely releasing pressure, gradually gasifying CO 2, and directionally depositing a precursor on the surface of a carrier;
(7) Hydrogen reduction, namely, introducing H 2/Ar mixed gas into a tubular furnace, heating to 300-400 ℃ at 2 ℃ per min, preserving heat for 2-3 hours to reduce Ir 3+、Ru3+ into a metal state, further heating to 450-550 ℃, preserving heat for 1-2 hours, and promoting alloying.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002136870A (en) * | 2000-11-07 | 2002-05-14 | Mitsui Eng & Shipbuild Co Ltd | Catalyst for treating exhaust gas |
| WO2003039740A1 (en) * | 2001-11-02 | 2003-05-15 | Conoco Inc. | Combustion deposited metal-metal oxide catalysts and process for producing synthesis gas |
| US20050081443A1 (en) * | 1999-02-08 | 2005-04-21 | Rita Aiello | Catalyst composition |
| CN1805694A (en) * | 2003-06-13 | 2006-07-19 | 菲利普莫里斯生产公司 | Catalyst for reducing carbon monoxide in mainstream cigarette smoke |
| CN105026041A (en) * | 2013-03-08 | 2015-11-04 | 巴斯夫公司 | Base metal catalyst and method of using same |
| US20170128881A1 (en) * | 2015-11-06 | 2017-05-11 | Paccar Inc | Diesel oxidation catalyst with minimal platinum group metal content |
| KR20240034399A (en) * | 2022-09-07 | 2024-03-14 | 한국에너지기술연구원 | COMPLEX CATALYST FOR SIMULATAEOUS REMOVING CO AND NOx, AND MANUFACTURE OF THE SAME |
| CN119524835A (en) * | 2024-10-17 | 2025-02-28 | 华电青岛环保技术有限公司 | Molybdenum-manganese composite metal oxide catalyst for efficient NO2 purification and its preparation method and application |
| CN119588346A (en) * | 2024-08-05 | 2025-03-11 | 清华大学 | Highly selective anti-carbon deposition CO oxidation catalyst and preparation method thereof |
-
2025
- 2025-03-12 CN CN202510285927.2A patent/CN120155176B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050081443A1 (en) * | 1999-02-08 | 2005-04-21 | Rita Aiello | Catalyst composition |
| JP2002136870A (en) * | 2000-11-07 | 2002-05-14 | Mitsui Eng & Shipbuild Co Ltd | Catalyst for treating exhaust gas |
| WO2003039740A1 (en) * | 2001-11-02 | 2003-05-15 | Conoco Inc. | Combustion deposited metal-metal oxide catalysts and process for producing synthesis gas |
| CN1805694A (en) * | 2003-06-13 | 2006-07-19 | 菲利普莫里斯生产公司 | Catalyst for reducing carbon monoxide in mainstream cigarette smoke |
| CN105026041A (en) * | 2013-03-08 | 2015-11-04 | 巴斯夫公司 | Base metal catalyst and method of using same |
| US20170128881A1 (en) * | 2015-11-06 | 2017-05-11 | Paccar Inc | Diesel oxidation catalyst with minimal platinum group metal content |
| KR20240034399A (en) * | 2022-09-07 | 2024-03-14 | 한국에너지기술연구원 | COMPLEX CATALYST FOR SIMULATAEOUS REMOVING CO AND NOx, AND MANUFACTURE OF THE SAME |
| CN119588346A (en) * | 2024-08-05 | 2025-03-11 | 清华大学 | Highly selective anti-carbon deposition CO oxidation catalyst and preparation method thereof |
| CN119524835A (en) * | 2024-10-17 | 2025-02-28 | 华电青岛环保技术有限公司 | Molybdenum-manganese composite metal oxide catalyst for efficient NO2 purification and its preparation method and application |
Non-Patent Citations (1)
| Title |
|---|
| CHOQUE, V ET AL.: "Study of ruthenium supported on Ta2O5-ZrO2 and Nb2O5-ZrO2 as catalysts for the partial oxidation of methane", 《CATALYSIS TODAY》, vol. 142, no. 3, 30 April 2009 (2009-04-30), pages 308 - 313, XP026061362, DOI: 10.1016/j.cattod.2008.09.013 * |
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