CN105268446B - Rear-earth-doped Ni bases BaTiO3‑TiO2Catalyst and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of chemical catalysts, and in particular relates to a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst and a preparation method thereof. The technical problem to be solved by the present invention is that the catalyst for the synthesis gas production by catalytic reforming of CH ₄ ‑CO ₂ is easily deactivated and the activity is not high, so that the average conversion rate of CH ₄ is low. The solution of the present invention to solve the above technical problems is to provide a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst. The chemical composition of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst is calculated by mass percentage: 0.15% to 0.3% of La ₂ O ₃ , 0.05% to 0.15% of CeO ₂ , and 7% to 9% of NiO , BaTiO ₃ is 80% to 88% and TiO ₂ is 2.55% to 10.8%. The present invention also provides a preparation method of the above-mentioned rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst. The catalyst provided by the invention has high catalytic activity, low carbon deposition rate and good high-temperature stability, and provides a new choice for the catalyst for the reaction of CH ₄ -CO ₂ catalytic reforming to prepare synthesis gas.

Description

Ni-based BaTiO3-TiO2 catalyst doped with rare earth and its preparation method

technical field

The invention belongs to the field of chemical catalysts, and in particular relates to a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst and a preparation method thereof.

Background technique

With the continuous growth of the economy and the depletion of oil resources, the global energy crisis is becoming more and more serious, and it is extremely urgent to find an alternative energy source. From the perspective of national security and energy strategy, the research and development of a new chemical production process that uses one carbon resource instead of petroleum as a raw material is of great significance to my country, a country with a lot of coal, little oil and rich methane resources. The world's natural gas reserves are very rich, with prospective reserves reaching 400 trillion cubic meters. my country's natural gas reserves reach 40 trillion cubic meters, accounting for about 10% of the world's total reserves. In 1995, the world's natural gas demand was 2.2 trillion cubic meters, accounting for 23% of the world's primary energy consumption. In 2010, it will reach 2.9-3.1 trillion cubic meters, accounting for 25%. By the end of 2006, the country's remaining recoverable natural gas reserves were about 3.09 trillion cubic meters, an increase of 0.24 trillion cubic meters over 2005, an increase of about 8.4%. Natural gas will be an important part of world energy in the 21st century. The content of CH ₄ in natural gas is about 75% to 90%, and the content of C ₂ to C ₃ is about 7% to 15%. Therefore, the development and utilization of natural gas is of great significance in terms of solving energy shortages, resource shortages, and environmental protection.

Natural gas, oilfield associated gas, coal bed methane and refinery gas contain a large amount of methane and other low-carbon alkanes. How to effectively convert methane and low-carbon alkanes into useful liquid substances and chemical Raw materials have extremely important application value. Methane and CO ₂ are the main greenhouse gases, and they are also one of the most stable molecules in chemistry. CH ₄ is a non-polar molecule similar to an inert gas. The CH bond energy is as high as 435kJ/mol, and it is thermodynamically very stable; CO ₂ It is also a very stable linear symmetric molecule. Their transformation is not only of great environmental significance, but also a challenge in the study of chemical theory. In recent years, the new process of producing syngas from methane with oxygen CO ₂ is attracting more and more attention because of its attractive environmental benefits and potential industrial application value. This process not only overcomes the inherent shortcomings of the two reactions of partial oxidation of methane and reforming of methane carbon dioxide to synthesis gas, but also has the special advantage of adjustable H ₂ /CO ratio. How to effectively activate such a stable molecule and then realize a reasonable transformation has become one of the most challenging topics in the field of heterogeneous catalysis. Compared with traditional steam reforming, the catalytic reforming of methane and carbon dioxide to produce synthesis gas has the advantages of less investment, high efficiency, low energy consumption, and a reasonable ratio of hydrogen to carbon monoxide in the synthesis gas. But this process is a strong endothermic reaction (ΔH=248kJ/mol), which requires a higher reaction temperature (800°C). Therefore, the development of catalysts with high activity, high selectivity and high stability is one of the key factors for the industrial application of methane catalytic reforming, and it is also a hot spot in this field of research. Synthesis of fuels and chemicals from methane via synthesis gas is one of the most efficient ways to utilize natural gas. It is said that in natural gas chemical products, 60% of the product cost and equipment are invested in the gas production part, so gas production has always been the focus of natural gas chemical development research. There are three methods for converting methane into synthesis gas: steam reforming, partial oxidation of methane, and _CO2 reforming, and their combinations. Among them, steam reforming has already been industrialized, but there are problems with high energy consumption, large investment, and the resulting synthesis gas _H2 /CO=3, not suitable for FT synthesis and other important follow-up processes.

The ratio of H ₂ /CO produced in the carbon dioxide reforming process of methane is about 1, which is an ideal raw material for Fischer-Tropsch synthesis and oxo synthesis. Carbon dioxide reforming of methane: CH ₄ +CO ₂ →2CO+2H ₂ , ΔH _298K =247.3 kJ/mol. This reaction utilizes the CO ₂ gas that causes the greenhouse effect, which is of great significance for mitigating air pollution and environmental governance. As early as 1928, foreign researchers loaded Fe, Co, Ni, Cu, etc. on clay, silica and other high-temperature-resistant mixtures, and found that the catalyst with Ni and Co as active components had a higher efficiency for methane carbon dioxide reforming to synthesis gas. active. However, more extensive research on this reaction began in the 1990s. In 1991, Ashcroft published a research paper on CH ₄ -CO ₂ reforming in Nature, which has aroused widespread interest of researchers worldwide since then. In the past ten years, scholars at home and abroad have carried out systematic research on the methane carbon dioxide reforming reaction. They have carried out extensive and in-depth research on the active components of the catalyst, the carrier, the auxiliary agent, and the reaction mechanism.

The patent with the application number 201310258286.9 uses Nd as the auxiliary agent, Ni as the active component, and ordered mesoporous silica (SBA-15) as the carrier. The rare earth metal Nd and The Ni/Nd/SBA-15 catalyst modified by rare earth metal Nd was prepared by loading the active metal component Ni on the carrier. The Ni/Nd/SBA-15 catalyst prepared by this invention shows higher activity and better anti-coking performance in the reaction of methane carbon dioxide reforming to synthesis gas, but it is still not high, and the average conversion rate of _CO2 is only 94.2%. , the average conversion of CH ₄ is only 82%.

The patent with the application number 201210275453 relates to a catalyst for the reformation of methane and carbon dioxide into gas. The catalyst is to support the active component metal nickel on MgO and MgAl ₂ O ₄ mixed oxide, and its general formula is Ni/MgO +MgAl ₂ O ₄ , the Ni content accounts for 3%-10% of the weight of the catalyst. The catalyst solves the problems of poor anti-coking ability, complicated preparation method and high catalyst cost existing in the existing catalysts. The preparation method described in the invention is simple, the synthesis conditions are easy to control, and it is easy to industrialize, and has the advantages of high catalytic activity, good anti-coking performance and stability, and lower cost than noble metal catalysts and nickel-based modified catalysts. However, its catalytic activity is still not high, and the average conversion rate of _CO2 is only 94%, and the average conversion rate of _CH4 is only 87%.

The research on CH ₄ -CO ₂ catalytic reforming to synthesis gas has made great progress, but there is still a certain gap to achieve industrialization. The main problem is that the catalyst is easily deactivated due to carbon deposition and sintering. Therefore, the development of catalysts with high activity, high selectivity and carbon deposition resistance has always been the goal pursued by researchers.

Contents of the invention

The technical problem to be solved by the present invention is that the catalyst for the synthesis gas production reaction by catalytic reforming of CH ₄ -CO ₂ is easily deactivated and the activity is not high, so that the average conversion rate of CH ₄ is low.

The solution of the present invention to solve the above technical problems is to provide a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst. The chemical composition of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst is calculated by mass percentage: 0.15% to 0.3% of La ₂ O ₃ , 0.05% to 0.15% of CeO ₂ , and 7% to 9% of NiO , BaTiO ₃ is 80% to 88% and TiO ₂ is 2.55% to 10.8%.

The present invention also provides a method for preparing the above-mentioned rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst, comprising the following steps:

a. Preparation of oxytitanic acid oxalate (H ₂ [TiO(C ₂ O ₄ ) ₂ ]) solution: take the concentrated TiOSO ₄ solution and dilute it with water at room temperature to obtain a dilute titanium solution, add ammonia water to adjust the pH value of the dilute titanium solution to 0.5 ~3. After the precipitation is complete, filter and wash to obtain orthotitanic acid (H ₄ TiO ₄ ) precipitate; add oxalic acid to the above orthotitanic acid precipitate, then add water to dissolve to obtain a mixed solution, and maintain the concentration of the mixed solution Calculated as _{TiO 2} is 0.7～1.3kg/L; the above mixed solution is heated to boiling and kept in boiling state for 0.5～1h to obtain oxytitanic acid oxalate solution; the addition amount of the oxalic acid is orthotitanic acid precipitation ) 2 times of the total molar amount; add ammonia water during the boiling process to keep the pH value of the solution at 1.5 to 2.5;

b. Preparation of rare earth-doped Ni-based barium chloride solution: mix barium chloride, nickel nitrate, lanthanum acetate (La(Ac) ₃ ) and cerium acetate (Ce(Ac) ₃ ) evenly, add water to dissolve completely, and obtain Rare earth-doped Ni-based barium chloride solution; the molar ratio of the barium chloride, nickel nitrate and orthotitanic acid precipitate (calculated as TiO ₂ ) is 1:0.15～0.25:1; the lanthanum acetate, cerium acetate and The molar ratio of barium chloride is 0.0005-0.002: 0.0005-0.002: 1, and the sum of the molar weights of lanthanum acetate and cerium acetate is 0.1%-0.4% of the molar weight of barium chloride;

c. At normal temperature, add the above-mentioned rare earth-doped Ni-based barium chloride solution to the obtained oxalate titanate solution in step a, and react for 1.5 to 2.5 hours to obtain rare-earth-doped Ni-based barium oxalate titanate (BaTiO (C ₂ O ₄ ) ₂ 4H ₂ O) precipitation system; the molar ratio of the molar weight of barium chloride in the Ni-based barium chloride solution doped with rare earth to the oxytitanic acid oxalate solution (calculated as TiO ₂ ) is 1:1;

d. Add metatitanic acid (H ₂ TiO ₃ ) to the above rare earth-doped Ni-based barium oxalate titanate precipitation system, mix thoroughly, then wash the precipitate, and filter with suction to obtain a filter cake. After the filter cake is dried, Then calcined at 750°C to 850°C for 2h to obtain a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier; the amount of metatitanic acid added is the molar amount of the orthotitanic acid precipitate (calculated as TiO ₂ ) described in step a 5% to 35%;

e. Immerse the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier in a saturated nickel nitrate solution for 20-60 minutes, then take it out, dry it, and then calcinate it in the air at 600°C-650°C for 2h, and finally Rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst is obtained by jet milling; in the saturated nickel nitrate solution, the molar ratio of nickel nitrate to barium titanate in the BaTiO ₃ -TiO ₂ carrier is 0.05-0.10:1.

Wherein, the concentration of the concentrated TiOSO ₄ solution described in step a is 180-250 g/L in terms of TiO ₂ . Preferably, the concentration of the concentrated TiOSO ₄ solution is 210-230 g/L calculated as TiO ₂ .

Wherein, the concentration of the dilute titanium solution in step a is 100-160 g/L as TiO ₂ . The concentration of the dilute titanium solution is preferably 130-150 g/L in terms of TiO ₂ .

As a preferred solution of the present invention, the pH value of the dilute titanium solution in step a is 1-2.

As a preferred solution of the present invention, the concentration of the mixed solution in step a is 0.9-1.1 kg/L calculated as TiO ₂ .

Wherein, the pH value of the mixed solution in step a is 1.9-2.1.

As a preferred solution of the present invention, the time for maintaining the boiling state in step a is 40-45 minutes.

As a preferred solution of the present invention, the sum of the molar weights of lanthanum acetate and cerium acetate in step b is 0.2%-0.3% of the molar weight of barium chloride.

Wherein, the rate of adding the rare earth-doped Ni-based barium chloride solution into the oxalate titanate solution in step c is 5-20 mL/min. Preferably, the rate at which the rare earth-doped Ni-based barium chloride solution is added to the oxytitanic acid oxalate solution is 10-15 mL/min.

As a preferred solution of the present invention, the reaction time in step c is 1.9 to 2.1 hours.

As a preferred solution of the present invention, the amount of metatitanic acid added in step d is 20% to 30% of the molar amount of orthotitanic acid precipitate (calculated as TiO ₂ ) obtained in step a.

As a preferred solution of the present invention, the soaking time in step e is 30-40 minutes.

The beneficial effect of the present invention is that: the present invention creatively adds rare earth and nickel nitrate in the process of carrier BaTiO ₃ formation, that is, adding it in the barium chloride solution, and its advantage is that the rare earth and NiO can be dispersed and adsorbed on the BaTiO ₃ matrix to the greatest possible extent. The surface and molecular gap greatly strengthen the specific surface area and surface adsorption energy. The present invention creatively adopts the mixed carrier of BaTiO ₃ and TiO ₂ to form complementary and strengthening, and replaces the position of Ti in the crystal lattice by a small amount of Ni, and utilizes the "matrix effect" of stable anatase structure to obtain highly dispersed and stable Ni Metal particles are used to prepare high-performance Ni-based catalysts, which not only maintain high catalytic activity, but also greatly inhibit carbon deposition, and have good high-temperature stability. The present invention also creatively uses two additives, La ₂ O ₃ and CeO ₂ , to make up for the defect of a single additive with a fixed atomic radius, which is beneficial to the improvement of the catalyst activity and greatly reduces the amount of carbon deposited on the catalyst after the reaction. And the thermal stability is also significantly enhanced.

Description of drawings

Figure 1 XRD diffraction pattern of rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst.

detailed description

The preparation method of the Ni-based BaTiO ₃ -TiO ₂ catalyst doped with rare earth comprises the following steps:

a. Preparation of oxytitanic acid oxalate (H ₂ [TiO(C ₂ O ₄ ) ₂ ]) solution: take the concentrated TiOSO ₄ solution and dilute it with water at room temperature to obtain a dilute titanium solution, add ammonia water to adjust the pH value of the dilute titanium solution to 0.5 ~3. After the precipitation is complete, filter and wash to obtain orthotitanic acid (H ₄ TiO ₄ ) precipitate; add oxalic acid to the above orthotitanic acid precipitate, then add water to dissolve to obtain a mixed solution, and maintain the concentration of the mixed solution Calculated as _{TiO 2} is 0.7～1.3kg/L; the above mixed solution is heated to boiling and kept in boiling state for 0.5～1h to obtain oxytitanic acid oxalate solution; the addition amount of the oxalic acid is orthotitanic acid precipitation ) 2 times of the total molar amount; add ammonia water during the boiling process to keep the pH value of the solution at 1.5 to 2.5;

b. Preparation of rare earth-doped Ni-based barium chloride solution: mix barium chloride, nickel nitrate, lanthanum acetate (La(Ac) ₃ ) and cerium acetate (Ce(Ac) ₃ ) evenly, add water to dissolve completely, and obtain Rare earth-doped Ni-based barium chloride solution; the molar ratio of the barium chloride, nickel nitrate and orthotitanic acid precipitate (calculated as TiO ₂ ) is 1:0.15～0.25:1; the lanthanum acetate, cerium acetate and The molar ratio of barium chloride is 0.0005-0.002: 0.0005-0.002: 1, and the sum of the molar weights of lanthanum acetate and cerium acetate is 0.1%-0.4% of the molar weight of barium chloride;

c. At normal temperature, add the above-mentioned rare earth-doped Ni-based barium chloride solution to the obtained oxalate titanate solution in step a, and react for 1.5 to 2.5 hours to obtain rare-earth-doped Ni-based barium oxalate titanate (BaTiO (C ₂ O ₄ ) ₂ 4H ₂ O) precipitation system; the molar ratio of the molar weight of barium chloride in the Ni-based barium chloride solution doped with rare earth to the oxytitanic acid oxalate solution (calculated as TiO ₂ ) is 1:1;

d. Add metatitanic acid (H ₂ TiO ₃ ) to the above rare earth-doped Ni-based barium oxalate titanate precipitation system, mix thoroughly, then wash the precipitate, and filter with suction to obtain a filter cake. After the filter cake is dried, Then calcined at 750°C to 850°C for 2h to obtain a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier; the amount of metatitanic acid added is the molar amount of the orthotitanic acid precipitate (calculated as TiO ₂ ) described in step a 5% to 35%;

e. Immerse the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier in a saturated nickel nitrate solution for 20-60 minutes, then take it out, dry it, and then calcinate it in the air at 600°C-650°C for 2h, and finally Rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst is obtained by jet milling; in the saturated nickel nitrate solution, the molar ratio of nickel nitrate to barium titanate in the BaTiO ₃ -TiO ₂ carrier is 0.05-0.10:1.

Wherein, the concentration of the concentrated TiOSO ₄ solution described in step a is 180-250 g/L in terms of TiO ₂ . The concentration of the concentrated TiOSO ₄ solution is preferably 210-230 g/L in terms of TiO ₂ .

Wherein, the concentration of the dilute titanium solution in step a is 100-160 g/L as TiO ₂ . The concentration of the dilute titanium solution is preferably 130-150 g/L in terms of TiO ₂ . If the concentration of dilute titanium solution is too high, it will not be easily hydrolyzed; if the concentration is too low, the precipitate after hydrolysis is difficult to filter.

Wherein, the pH value of the dilute titanium solution in step a is adjusted by ammonia water. The advantage of choosing ammonia water is that the ammonia water is neither a strong alkali nor metal impurity ions.

As a preferred solution of the present invention, the pH value of the dilute titanium solution in step a is 1-2. If the pH value is too low, it will not be easily hydrolyzed; if the pH value is too high, it will easily generate metatitanic acid (H ₂ TiO ₃ ).

As a preferred solution of the present invention, the concentration of the mixed solution in step a is 0.9-1.1 kg/L calculated as TiO ₂ .

Wherein, the pH value of the mixed solution in step a is 1.9-2.1.

As a preferred solution of the present invention, the time for maintaining the boiling state in step a is 40-45 minutes.

As a preferred solution of the present invention, the sum of the molar weights of lanthanum acetate and cerium acetate in step b is 0.2%-0.3% of the molar weight of barium chloride. If the sum of the molar weights of lanthanum acetate and cerium acetate is too high or too low, the activity of the catalyst will be reduced.

Wherein, the rate of adding the rare earth-doped Ni-based barium chloride solution into the oxalate titanate solution in step c is 5-20 mL/min. Preferably, the rate at which the rare earth-doped Ni-based barium chloride solution is added to the oxytitanic acid oxalate solution is 10-15 mL/min. If the above-mentioned addition rate is too high, it is not conducive to the formation of nano-scale barium oxalate titanate, and it is easy to cause coarse particles; if the rate is too low, the efficiency will be reduced.

As a preferred solution of the present invention, the reaction time in step c is 1.9 to 2.1 hours.

As a preferred solution of the present invention, the amount of metatitanic acid added in step d is 20% to 30% of the molar amount of orthotitanic acid precipitate (calculated as TiO ₂ ) obtained in step a.

As a preferred solution of the present invention, the soaking time in step e is 30-40 minutes.

Example 1

Take 2L of concentrated TiOSO ₄ solution (calculated as TiO ₂ , the concentration is 220g/L), add 0.5L deionized water to fully stir, and drop ammonia water at the same time to keep the pH value of the solution at 1.0. After the acid (H ₄ TiO ₄ ) was stabilized, it was filtered and washed. At the same time, the mass percentage of TiO ₂ contained in the ortho-titanic acid slurry was calculated by taking a small amount of ortho-titanic acid and calcining at a high temperature of 900° C., and weighing the mass of TiO ₂ powder. Weigh 29.98 g (calculated as TiO ₂ ) of orthotitanic acid slurry for use.

Weigh 94.64g of oxalic acid crystals (equivalent to ₂ times the total molar amount of TiO in ortho-titanic acid), and add it into the ortho-titanic acid slurry in the previous step. Add distilled water to bring the total volume to 400mL, heat it to boiling, adjust its pH value to 2.0 with ammonia water, continue to boil, after boiling for 45min, transparent oxytitanic acid oxalate (H ₂ [TiO(C ₂ O ₄ ) ₂ ] ) solution.

Weigh 84.92g of barium chloride, and add distilled water to 850mL to fully dissolve it.

Weigh nickel nitrate and dissolve it in 100mL distilled water, and the nickel nitrate weighs 28% of the molar weight of barium chloride in the previous step.

Add a certain amount of lanthanum acetate (equivalent to 60% of the total amount of rare earth acetate) and cerium acetate (equivalent to 40% of the total amount of rare earth acetate) in the barium chloride solution. 0.25%. Add 50% of the mass of nickel nitrate in the previous step at the same time, and fully stir.

After the transparent oxytitanic acid oxalate solution is formed, add the rare earth-doped Ni-based barium chloride solution at a rate of 10mL/min to the transparent solution of oxytitanic oxalate at room temperature, and precipitate under stirring 2h, a rare earth-doped Ni-based barium oxalate titanate (BaTiO(C ₂ O ₄ ) ₂ ·4H ₂ O) precipitation system was obtained.

Slowly add metatitanic acid (H ₂ TiO ₄ ) into the rare earth-doped Ni-based barium oxalate titanate precipitation system in the previous step, the amount added is the orthotitanic acid slurry (29.98g) obtained in the first step 20% of the molar weight (calculated as TiO ₂ ).

Wash and filter the precipitate obtained in the previous step to obtain a filter cake, dry it at 120°C and then calcinate it at 800°C for 2 hours to obtain NiO, La ₂ O ₃ and CeO ₂ and evenly disperse on the surface of BaTiO ₃ and TiO ₂ tiny particles and the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ support in the interstitial.

Using the conventional impregnation method, the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier obtained in the previous step was immersed in the remaining nickel nitrate solution, baked in a muffle furnace (120°C) for 24h to dryness, and then placed in the air for 600 Calcined at ℃～650℃ for 2h, and obtained the catalyst after jet crushing.

The composition of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst obtained in this example is calculated by mass percentage: 0.20% of La ₂ O ₃ , 0.07% of CeO ₂ , 8.59% of NiO, 85.29% of BaTiO ₃ , _TiO2 is 5.85%.

The test results show that: among the catalytic activity indicators, the average conversion rate of CO ₂ is 98.1%, the average conversion rate of CH ₄ is 96.3%, and the carbon deposition rate is 0.6%.

Example 2

Take 2L of concentrated TiOSO ₄ solution (calculated as TiO ₂ , the concentration is 220g/L), add 0.5L deionized water to fully stir, and drop ammonia water at the same time to keep the pH value of the solution at 1.0. After the acid (H ₄ TiO ₄ ) was stabilized, it was filtered and washed. At the same time, the mass percentage of TiO ₂ contained in the ortho-titanic acid slurry was calculated by taking a small amount of ortho-titanic acid and calcining at a high temperature of 900° C., and weighing the mass of TiO ₂ powder. Weigh 29.98 g (calculated as TiO ₂ ) of orthotitanic acid slurry for use.

Weigh 94.64g of oxalic acid crystals (equivalent to ₂ times the total molar amount of TiO in ortho-titanic acid), and add it into the ortho-titanic acid slurry in the previous step. Add distilled water to bring the total volume to 400mL, heat it to boiling, adjust its pH value to 2.0 with ammonia water, continue to boil, after boiling for 45min, transparent oxytitanic acid oxalate (H ₂ [TiO(C ₂ O ₄ ) ₂ ] ) solution.

Weigh 84.92g of barium chloride, and add distilled water to 850mL to fully dissolve it.

Weigh nickel nitrate and dissolve it in 100mL of distilled water, and nickel nitrate weighs 24% of the molar weight of barium chloride in the previous step.

Add a certain amount of lanthanum acetate (equivalent to 40% of the total amount of rare earth acetate) and cerium acetate (equivalent to 60% of the total amount of rare earth acetate) in the barium chloride solution. 0.25%. At the same time, 50% of the mass of nickel nitrate in the previous step was added, and fully stirred to obtain a rare earth-doped Ni-based barium chloride solution.

After the transparent oxytitanic acid oxalate solution is formed, add the rare earth-doped Ni-based barium chloride solution at a rate of 10mL/min to the transparent solution of oxytitanic oxalate at room temperature, and precipitate under stirring 2h, a rare earth-doped Ni-based barium oxalate titanate (BaTiO(C ₂ O ₄ ) ₂ ·4H ₂ O) precipitation system was obtained.

Slowly add metatitanic acid (H ₂ TiO ₄ ) into the rare earth-doped Ni-based barium oxalate titanate precipitation system in the previous step, the amount added is the orthotitanic acid slurry (29.98g) obtained in the first step 30% of the molar weight (calculated as TiO ₂ ).

Wash and filter the precipitate obtained in the previous step to obtain a filter cake, dry it at 120°C and then calcinate it at 800°C for 2 hours to obtain NiO, La ₂ O ₃ and CeO ₂ and evenly disperse on the surface of BaTiO ₃ and TiO ₂ tiny particles and rare earth-doped Ni-based supports in the interstitial.

Using the conventional impregnation method, the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier is immersed in the remaining nickel nitrate solution, baked in a muffle furnace (120°C) for 24h to dry, and then heated in the air at 600°C to 650°C Calcined under the condition for 2h, and obtained the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst by jet crushing.

The composition of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst obtained in this example is as follows: 0.13% La ₂ O ₃ , 0.10% CeO ₂ , 7.25% NiO, 83.95% BaTiO ₃ , 8.61% TiO ₂ .

The test results show that: among the catalytic activity indicators, the average conversion rate of CO ₂ is 98.0%, the average conversion rate of CH ₄ is 96.5%, and the carbon deposition rate is 0.7%.

Example 3

Take 2L of concentrated TiOSO ₄ solution (calculated as TiO ₂ , the concentration is 220g/L), add 0.5L deionized water to fully stir, and drop ammonia water at the same time to keep the pH value of the solution at 1.0. After the acid (H ₄ TiO ₄ ) was stabilized, it was filtered and washed. At the same time, the mass percentage of TiO ₂ contained in the ortho-titanic acid slurry was calculated by taking a small amount of ortho-titanic acid and calcining at a high temperature of 900° C., and weighing the mass of TiO ₂ powder. Weigh 29.98 g (calculated as TiO ₂ ) of orthotitanic acid slurry for use.

Weigh 94.64g of oxalic acid crystals (equivalent to ₂ times the total molar amount of TiO in ortho-titanic acid), and add it into the ortho-titanic acid slurry in the previous step. Add distilled water to bring the total volume to 400mL, heat it to boiling, adjust its pH value to 2.0 with ammonia water, continue to boil, after boiling for 45min, transparent oxytitanic acid oxalate (H ₂ [TiO(C ₂ O ₄ ) ₂ ] ) solution.

Weigh 84.92g of barium chloride, and add distilled water to 850mL to fully dissolve it.

Weigh nickel nitrate and dissolve it in 100mL distilled water, and the nickel nitrate weighs 28% of the molar weight of barium chloride in the previous step.

Add a certain amount of lanthanum acetate (equivalent to 60% of the total amount of rare earth acetate) and cerium acetate (equivalent to 40% of the total amount of rare earth acetate) in the barium chloride solution. 0.3%. At the same time, 80% of the mass of nickel nitrate in the previous step was added, and fully stirred to obtain a rare earth-doped Ni-based barium chloride solution.

After the transparent oxytitanic acid oxalate solution is formed, add the rare earth-doped Ni-based barium chloride solution at a rate of 10mL/min to the transparent solution of oxytitanic oxalate at room temperature, and precipitate under stirring 2h, a rare earth-doped Ni-based barium oxalate titanate (BaTiO(C ₂ O ₄ ) ₂ ·4H ₂ O) precipitation system was obtained.

Slowly add metatitanic acid (H ₂ TiO ₄ ) into the rare earth-doped Ni-based barium oxalate titanate precipitation system in the previous step, the amount added is the orthotitanic acid slurry (29.98g) obtained in the first step 20% of the molar weight (calculated as TiO ₂ ).

Wash and filter the precipitate obtained in the previous step to obtain a filter cake, dry it at 120°C and then calcinate it at 800°C for 2 hours to obtain NiO, La ₂ O ₃ and CeO ₂ and evenly disperse on the surface of BaTiO ₃ and TiO ₂ tiny particles and the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ support in the interstitial.

Using the conventional impregnation method, the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier is immersed in the remaining nickel nitrate solution, baked in a muffle furnace (120°C) for 24h to dry, and then heated in the air at 600°C to 650°C Calcined under the condition for 2h, and obtained the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst by jet crushing.

The composition of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst obtained in this example is as follows: 0.24% La ₂ O ₃ , 0.08% CeO ₂ , 8.59% NiO, 85.25% BaTiO ₃ , 5.85% TiO ₂ .

The test results show that: among the catalytic activity indicators, the average conversion rate of CO ₂ is 98.9%, the average conversion rate of CH ₄ is 98.5%, and the carbon deposition rate is 0.3%.

Comparative example:

Take 2L of concentrated TiOSO ₄ solution (calculated as TiO ₂ , the concentration is 220g/L), add 0.5L deionized water to fully stir, and drop ammonia water at the same time to keep the pH value of the solution at 1.0. After the acid (H ₄ TiO ₄ ) was stabilized, it was filtered and washed. At the same time, the mass percentage of TiO ₂ contained in the ortho-titanic acid slurry was calculated by taking a small amount of ortho-titanic acid and calcining at a high temperature of 900° C., and weighing the mass of TiO ₂ powder. Weigh 29.98 g (calculated as TiO ₂ ) of orthotitanic acid slurry for use.

Weigh 94.64g of oxalic acid crystals (equivalent to ₂ times the total molar amount of TiO in ortho-titanic acid), and add it into the ortho-titanic acid slurry in the previous step. Add distilled water to bring the total volume to 400mL, heat it to boiling, adjust its pH value to 2.0 with ammonia water, continue to boil, after boiling for 45min, transparent oxytitanic acid oxalate (H ₂ [TiO(C ₂ O ₄ ) ₂ ] ) solution.

Weigh 84.92g of barium chloride, and add distilled water to 850mL to fully dissolve it.

After the transparent oxytitanic acid oxalate solution is formed, at room temperature, add the barium chloride solution obtained in the previous step into the transparent oxalotitanic acid oxytitanic solution at a rate of 10 mL/min, and precipitate for 2 hours while stirring. A barium oxalate titanate (BaTiO(C ₂ O ₄ ) ₂ ·4H ₂ O) precipitation system was obtained.

Metatitanic acid (H ₂ TiO ₄ ) was slowly added to the barium oxalate titanate precipitation system in the previous step, and the amount added was 20% ( Calculated as _TiO2 ).

Add a certain amount of lanthanum acetate (equivalent to 60% of the total amount of rare earth acetate) and cerium acetate (equivalent to 40% of the total amount of rare earth acetate) in the mixed precipitation of barium oxalate titanate and metatitanic acid BaTiO ₃ -TiO ₂ , the addition of rare earth acetate is 0.25% of the molar weight of barium chloride crystals. Add nickel nitrate solution simultaneously (weigh nickel nitrate and dissolve in 100mL distilled water, nickel nitrate weighs 28% of the barium chloride molar weight of the previous step), fully stir.

The precipitate obtained in the previous step was washed, filtered with suction to obtain a filter cake, dried at 120°C, and then calcined at 800°C for 2 hours to obtain a catalyst carrier.

Using the conventional impregnation method, the catalyst carrier is immersed in the remaining nickel nitrate solution, baked in a muffle furnace (120°C) for 24h to dryness, and then calcined in the air at 600°C-650°C for 2h, and the titanium is obtained by jet crushing. Barium acid based catalyst.

The composition of the barium titanate-based catalyst obtained in this comparative example is as follows: 0.20% La ₂ O ₃ , 0.07% CeO ₂ , 8.59% NiO, 85.29% BaTiO ₃ , 5.85% TiO ₂ . Although the chemical composition of the barium titanate-based catalyst obtained in the comparative example is the same as that of Example 1, because the rare earth and nickel are added after the carrier BaTiO ₃ -TiO ₂ is precipitated, the dispersion and structure of the catalytically active components are different from those in the implementation. Examples 1 to 3 are different.

The test results show that: among the catalytic activity indicators, the average conversion rate of CO ₂ is 96.3%, the average conversion rate of CH ₄ is 94.2%, and the carbon deposition rate is 0.9%, which are obviously worse than those in Examples 1-3.

Claims (13)

1. Rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst, its chemical composition is calculated by mass percentage: La ₂ O ₃ is 0.15% to 0.3%, CeO ₂ is 0.05% to 0.15%, NiO is 7% to 9% %, BaTiO ₃ is 80% to 88% and TiO ₂ is 2.55% to 10.8%; The preparation method of the Ni-based BaTiO ₃ -TiO ₂ catalyst doped with rare earth comprises the following steps: a. Preparation of oxytitanic acid oxalate solution: take the concentrated _TiOSO4 solution and dilute it with water at room temperature to obtain dilute titanium solution, add ammonia water to adjust the pH value of the dilute titanium solution to 0.5-3, and after the precipitation is complete, filter and wash to obtain positive titanium solution. Titanic acid precipitation; add oxalic acid to the above orthotitanic acid precipitation, and then add water to dissolve to obtain a mixed solution, and keep the concentration of the mixed solution calculated as _TiO2 at 0.7-1.3kg/L; heat the above mixed solution to boiling, Maintain the boiling state for 0.5 to 1 hour to obtain oxytitanic acid oxalate solution; the amount of oxalic acid added is twice the total molar amount of orthotitanic acid precipitation; ammonia water is added during the boiling process to keep the pH value of the solution at 1.5 to 2.5; the Orthotitanic acid precipitation is calculated as TiO ₂ ; b, the preparation of the Ni-based barium chloride solution doped with rare earth: mix barium chloride, nickel nitrate, lanthanum acetate and cerium acetate uniformly, add water and dissolve completely, obtain the Ni-based barium chloride solution doped with rare earth; The molar ratio of barium chloride, nickel nitrate and orthotitanic acid precipitation is 1:0.15～0.25:1; the molar ratio of said lanthanum acetate, cerium acetate and barium chloride is 0.0005～0.002︰0.0005～0.002︰1, and the lanthanum acetate The sum of the molar weights of cerium acetate and cerium acetate is 0.1% to 0.4% of the molar weight of barium chloride; the orthotitanic acid precipitation is calculated as TiO ₂ ; c. At room temperature, add the above-mentioned rare earth-doped Ni-based barium chloride solution to the oxalate titanate solution obtained in step a, and react for 1.5 to 2.5 hours to obtain a rare-earth-doped Ni-based barium oxalate titanate precipitation system ; The molar ratio of the molar weight of barium chloride in the rare earth-doped Ni-based barium chloride solution to the oxytitanic oxalate solution is 1:1; the oxytitanic oxalate solution is calculated as TiO ₂ ; d. Add metatitanic acid to the above-mentioned rare earth-doped Ni-based barium oxalate titanate precipitation system, mix thoroughly, then wash the precipitate, filter with suction to obtain a filter cake, and dry the filter cake at 750°C to 850°C Calcining at ℃ for 2 hours to obtain a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier; the amount of metatitanic acid added is 5% to 35% of the molar weight of orthotitanic acid precipitated in step a; the orthotitanic acid Precipitation is calculated as _TiO2 ; e. Immerse the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier in a saturated nickel nitrate solution for 20-60 minutes, then take it out, dry it, and then calcinate it in the air at 600°C-650°C for 2h, and finally Rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst is obtained by jet milling; in the saturated nickel nitrate solution, the molar ratio of nickel nitrate to barium titanate in the BaTiO ₃ -TiO ₂ carrier is 0.05-0.10:1. 2. The preparation method of the Ni-based BaTiO ₃ -TiO ₂ catalyst doped with rare earth according to claim 1, characterized in that: comprising the following steps: a. Preparation of oxytitanic acid oxalate solution: take the concentrated _TiOSO4 solution and dilute it with water at room temperature to obtain dilute titanium solution, add ammonia water to adjust the pH value of the dilute titanium solution to 0.5-3, and after the precipitation is complete, filter and wash to obtain positive titanium solution. Titanic acid precipitation; add oxalic acid to the above orthotitanic acid precipitation, and then add water to dissolve to obtain a mixed solution, and keep the concentration of the mixed solution calculated as _TiO2 at 0.7-1.3kg/L; heat the above mixed solution to boiling, Maintain the boiling state for 0.5 to 1 hour to obtain oxytitanic acid oxalate solution; the amount of oxalic acid added is twice the total molar amount of orthotitanic acid precipitation; ammonia water is added during the boiling process to keep the pH value of the solution at 1.5 to 2.5; the Orthotitanic acid precipitation is calculated as TiO ₂ ; b, the preparation of the Ni-based barium chloride solution doped with rare earth: mix barium chloride, nickel nitrate, lanthanum acetate and cerium acetate uniformly, add water and dissolve completely, obtain the Ni-based barium chloride solution doped with rare earth; The molar ratio of barium chloride, nickel nitrate and orthotitanic acid precipitation is 1:0.15～0.25:1; the molar ratio of said lanthanum acetate, cerium acetate and barium chloride is 0.0005～0.002︰0.0005～0.002︰1, and the lanthanum acetate The sum of the molar weights of cerium acetate and cerium acetate is 0.1% to 0.4% of the molar weight of barium chloride; the orthotitanic acid precipitation is calculated as TiO ₂ ; c. At room temperature, add the above-mentioned rare earth-doped Ni-based barium chloride solution to the oxalate titanate solution obtained in step a, and react for 1.5 to 2.5 hours to obtain a rare-earth-doped Ni-based barium oxalate titanate precipitation system ; The molar ratio of the molar weight of barium chloride in the rare earth-doped Ni-based barium chloride solution to the oxytitanic oxalate solution is 1:1; the oxytitanic oxalate solution is calculated as TiO ₂ ; d. Add metatitanic acid to the above-mentioned rare earth-doped Ni-based barium oxalate titanate precipitation system, mix thoroughly, then wash the precipitate, filter with suction to obtain a filter cake, and dry the filter cake at 750°C to 850°C Calcining at ℃ for 2 hours to obtain a rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier; the amount of metatitanic acid added is 5% to 35% of the molar weight of orthotitanic acid precipitated in step a; the orthotitanic acid Precipitation is calculated as _TiO2 ; e. Immerse the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ carrier in a saturated nickel nitrate solution for 20-60 minutes, then take it out, dry it, and then calcinate it in the air at 600°C-650°C for 2h, and finally Rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst is obtained by jet milling; in the saturated nickel nitrate solution, the molar ratio of nickel nitrate to barium titanate in the BaTiO ₃ -TiO ₂ carrier is 0.05-0.10:1. 3. The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 2, characterized in that: the concentration of the concentrated TiOSO ₄ solution in step a is 180-250 g/L in terms of TiO ₂ . 4. The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 3, characterized in that: the concentration of the concentrated TiOSO ₄ solution is 210-230 g/L calculated as TiO ₂ . 5. The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 2, characterized in that: the concentration of the dilute titanium solution in step a is 100-160 g/L calculated as TiO ₂ . 6 . The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 5 , characterized in that: the concentration of the diluted titanium solution is 130-150 g/L calculated as TiO ₂ . 7. The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 2, characterized in that: the pH value of the dilute titanium solution in step a is 1 to 2; the concentration of the mixed solution is Calculated as TiO ₂ , it is 0.9-1.1kg/L; the time for maintaining the boiling state is 40-45min. 8. according to the preparation method of the Ni-based BaTiO ₃ -TiO ₂ catalyst of rare earth doping described in claim 2, it is characterized in that: the sum of the molar weights of lanthanum acetate and cerium acetate described in the step b is barium chloride molar weight 0.2% to 0.3%. 9. The preparation method of the Ni-based BaTiO ₃ -TiO ₂ catalyst doped with rare earth according to claim 2, characterized in that: the Ni-based barium chloride solution doped with rare earth described in step c is added to the oxytitanic acid oxalate solution The speed is 5-20mL/min. 10. according to the preparation method of the Ni-based BaTiO ₃ -TiO ₂ catalysts doped with rare earths according to claim 9, it is characterized in that: the speed at which the Ni-based barium chloride solution doped with rare earths is added to the oxalate oxytitanic acid solution It is 10-15mL/min. 11. The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 2, characterized in that the reaction time in step c is 1.9-2.1 h. 12. The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 2, characterized in that: the amount of metatitanic acid added in step d is 20% of the molar weight of the precipitated orthotitanic acid obtained in step a ~30%; the orthotitanic acid precipitate is calculated as TiO ₂ . 13. The preparation method of the rare earth-doped Ni-based BaTiO ₃ -TiO ₂ catalyst according to claim 2, characterized in that the impregnation time in step e is 30-40 min.