Catalytic conversion method for decomposing carbon dioxide into carbon monoxide

Abstract

The invention discloses a catalytic conversion method for decomposing carbon dioxide into carbon monoxide, which is characterized by comprising the following steps of: 1, adsorbing carbon dioxide molecules and added hydrogen molecules on the surface of a biomass activated carbon / Rh2O3 / NiO phase material to form an adsorption state structure, decomposing the hydrogen molecules into adsorption state hydrogen atoms, and forming an adsorption state structure; reacting carbon dioxide with part of hydrogen atoms to generate carboxyl; and 2, reacting the generated adsorption-state carboxyl with the remaining hydrogen atoms to remove a water molecule so as to form adsorption-state carbon monoxide molecules, and desorbing the adsorption-state carbon monoxide into a free state at a reaction high temperature so as to obtain carbon monoxide gas. According to the method, the carbon dioxide can be decomposed and converted into carbon monoxide more efficiently and stably, and large-scale production and preparation are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of polluted gas decomposition treatment, and in particular to a catalytic conversion method for decomposing carbon dioxide into carbon monoxide. Background Art

[0002] Carbon dioxide is one of the main pollutants emitted by industrial production, building operation and human metabolism. In order to better achieve the goals of carbon peak and carbon neutrality, it is necessary to further develop methods for purifying carbon dioxide by means of adsorption capture, underground storage and other means. In addition, carbon dioxide can also be catalytically converted into valuable carbon monoxide gas, so that carbon dioxide can be recycled multiple times, producing the effect of turning waste into treasure.

[0003] CN117548144A has disclosed a metal-loaded mesoporous cerium-based MOFs and its preparation method and application; CN116083949A has disclosed a MXene-loaded Ag-ZnO electrocatalyst and its preparation method, application and testing method; CN116043258A has disclosed a self-supporting copper selenide nanosheet electrocatalyst preparation method and application; and CN114799197A has disclosed a copper-antimony single-atom alloy catalyst preparation method and carbon dioxide reduction application. The above patent schemes can all achieve the preparation process of carbon dioxide decomposition and conversion into carbon monoxide. However, these existing catalysts for the catalytic conversion of carbon dioxide to methane, when used, the liquid water generated by the reaction will isolate the gaseous carbon dioxide from the contact with the solid catalyst surface, thereby seriously affecting the catalytic conversion efficiency of carbon dioxide and failing to meet the requirements of rapid and large-scale generation of carbon monoxide fuel. Therefore, the existing catalytic conversion decomposition materials still have the defects of poor overall rate and poor catalyst stability, which is difficult to meet the needs of rapid conversion and utilization of carbon dioxide.

[0004] Therefore, how to provide a catalytic conversion method that is different from the prior art and can more efficiently and stably decompose carbon dioxide into carbon monoxide has become a problem that needs to be considered and solved by those skilled in the art. Summary of the invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is: how to provide a catalytic conversion method for decomposing carbon dioxide into carbon monoxide that can more efficiently and stably achieve the decomposition and conversion of carbon dioxide, so as to make it more conducive to large-scale production and preparation.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A catalytic conversion method for decomposing carbon dioxide into carbon monoxide, characterized in that it comprises the following steps: In the first step, carbon dioxide molecules and added hydrogen molecules are adsorbed on the surface of biomass activated carbon / Rh2O3 / NiO phase material to form an adsorbed structure, hydrogen molecules are decomposed into adsorbed hydrogen atoms, and carbon dioxide reacts with some hydrogen atoms to generate carboxyl groups; the reaction process includes the following reaction formula: CO2(free) + Rh2O3 / NiO@C → CO2(ad), H2(free) + Rh2O3 / NiO@C → 2*H (ad), CO2 (ad) + *H (ad) → COOH (ad); In the second step, the generated adsorbed carboxyl group reacts with the remaining hydrogen atom to release a water molecule to form an adsorbed carbon monoxide molecule, and the adsorbed carbon monoxide is desorbed to a free state at a high reaction temperature to obtain carbon monoxide gas; the reaction process includes the following reaction formula: COOH (ad) + *H (ad) → CO (ad) + H2O, CO(ad) + energy → CO(free).

[0007] As an optimization, the biomass activated carbon adopts rice husk-based biomass activated carbon. It is easy to prepare and has better porosity, with an average specific surface area of ​​>1500 m 2 / g.

[0008] Thus, the present invention uses biomass activated carbon embedded with Rh2O3 and NiO as a catalytic conversion decomposition material for carbon dioxide decomposition, and can quickly and efficiently decompose carbon dioxide through the above reaction process. In this process, firstly, the biomass activated carbon has a large specific surface area (as mentioned above, the average specific surface area> 1500 m 2 / g), which can provide a large number of adsorption sites for the adsorption of carbon dioxide and hydrogen molecules; secondly, the functional components Rh2O3 and NiO embedded in activated carbon can be used to catalyze the formation of carboxyl groups and catalyze the formation of water molecules, respectively. The synergistic cooperation of the two can greatly increase the efficiency of the catalytic conversion of carbon dioxide into carbon monoxide.

[0009] Therefore, further, in the present invention, a carbon dioxide catalytic decomposition material whose main effective components are biomass activated carbon / Rh2O3 / NiO phase is used to achieve catalytic decomposition treatment of carbon dioxide.

[0010] In the above-mentioned carbon dioxide catalytic decomposition materials, biomass activated carbon serves as a matrix for loading effective ingredients Rh2O3 and NiO and capturing and adsorbing carbon dioxide and hydrogen molecules, and is the base bed for the catalytic reaction. The specific reaction process principle is as follows.

[0011] (a) The role of Rh2O3. For the step of hydrogenating carbon dioxide to form a carboxyl group in the basic process of catalytic conversion of carbon dioxide to carbon monoxide, one of the bonds in the C=O double bond needs to be broken, and then the O atom forms a bond with the adsorbed H atom. Since the Rh atom in Rh2O3 has an active electron in the outer layer, it can form a bond with an active electron in the outer layer of C in CO2, thereby promoting the breaking of a single bond in the above C=O double bond. At the same time, a more basic role is that there are unpaired electrons in the four orbits of the outer layer of the Rh atom, and the probability and intensity of its attraction-bonding effect on the adsorbed H atom are high, which can easily form multiple Rh(Rh2O3)-O(CO2) valence bonds, further enhancing the partial breaking of the C=O double bond. In addition, the supplementary promoting effect is that part of CO2 can be directly adsorbed on the O atom in Rh2O3, and then the C atom can directly bond with this O atom, thereby reducing a C=O double bond to a CO single bond for subsequent bonding with the adsorbed H atom.

[0012] (b) The role of NiO. For the carboxyl hydrogenation and dehydration formation step in the above-mentioned basic process of catalytic conversion of carbon dioxide to carbon monoxide, it requires the hydroxyl group to break off from the carboxyl group and combine with another adsorbed H atom. This process involves the breaking of the CO bond. Since the outer layer of the Ni atom in NiO has 5 active valence electrons, it can migrate across the entire surface through the delocalized π bonds on the porous carbon surface. When it migrates to the carboxyl group, it can combine with the O atom in -OH to form a free radical form, thereby destroying the CO bond and quickly combining with another adsorbed H atom. At the same time, a more basic role is that the H atom formed after the decomposition of the hydrogen molecule is more easily adsorbed on the O atom in NiO. This is because there are still 3 valence electrons on the Ni surface in NiO, which can form a Ni···H structure with the H atom, which can significantly fix the free H atoms and attract the H atoms originally dispersed at different sites on the porous activated carbon surface to gather around the NiO group, further increasing the rate of the carboxyl hydrogenation and dehydration reaction. It should be noted that the Rh2O3 group also has the above-mentioned function of combining with H atoms of NiO, but because Rh in Rh2O3 has only one outer active valence electron left, its ability to aggregate adsorbed H atoms is lower than that of NiO, and it does not serve as the main functional component of the carboxyl hydrogenation and dehydration step.

[0013] Therefore, the present invention can be used for the industrial production of carbon dioxide decomposition and conversion of carbon monoxide, and the carbon dioxide and hydrogen passing through can be quickly catalytically decomposed into carbon monoxide and water under the action of the catalyst, reducing the harm of carbon dioxide emissions to the environment and turning waste into treasure; it can improve the efficiency of carbon dioxide catalytic decomposition. The applicant has verified that the present invention can increase the Faraday efficiency of carbon monoxide generation from 80% to 95%+; and make the Faraday efficiency loss less than 5% after 6 hours of catalytic conversion of carbon dioxide.

[0014] Furthermore, the carbon dioxide catalytic decomposition material used in the present invention includes the following phase components in the following mass proportions: 0.01-0.15 parts of biomass activated carbon phase, 0.01-0.08 parts of Rh2O3 phase, 0.01-0.11 parts of NiO phase, and 0.66-0.097 parts of biomass activated carbon / Rh2O3 / NiO phase.

[0015] Further better mass ratios are: 0.02 parts of biomass activated carbon phase, 0.08 parts of Rh2O3 phase, 0.11 parts of NiO phase, and 0.79 parts of biomass activated carbon / Rh2O3 / NiO phase.

[0016] Among the above-mentioned carbon dioxide catalytic decomposition materials, the biomass activated carbon / Rh2O3 / NiO phase is the main site for the carbon dioxide catalytic decomposition reaction and therefore accounts for a relatively large proportion. The biomass activated carbon phase, Rh2O3 phase and NiO phase are common reaction products and can also be used to provide reaction sites and assist in enhancing the carbon dioxide catalytic decomposition process. Moreover, the components of each phase can have a certain dynamic conversion and supplement effect, thereby better ensuring the durability of the treatment effect.

[0017] Furthermore, the carbon dioxide catalytic decomposition material is prepared by the following steps: Step 1: First obtain biomass activated carbon as a substrate; Step 2: Complete the generation and loading of rhodium trioxide and nickel oxide; pour 20 g of the above biomass activated carbon into 500 ml of ultrapure water, and add 0.25 mol of dihydrated rhodium nitrate (Rh(NO3)3·2H2O) and 0.15 mol of hexahydrated nickel nitrate (Ni(NO3)2·6H2O) to form a mixed solution; then, stir the obtained mixed solution evenly, dry it and grind it into powder (as an optimization, the drying and grinding process is to place it in a magnetic stirrer and stir it continuously at 200 r / min and 50 ° C for 2 h; then, place the mixed solution in an oven at 70 ℃ to evaporate all water to obtain agglomerates, and grind the agglomerates into 200 mesh powder; thus completing the loading first can better ensure the subsequent calcination reaction generation effect); then, the obtained powder is calcined to obtain a porous activated carbon-supported rhodium trioxide (Rh2O3) / nickel oxide (NiO) composite catalyst (as an optimization, the calcination process is: the above-mentioned 200 mesh powder is placed in a muffle furnace and continuously calcined at 850 ℃ for 5 h (the heating rate from room temperature to 500 ℃ is 50 ℃ / min), and then naturally cooled to room temperature by ventilation to obtain a porous activated carbon-supported rhodium trioxide (Rh2O3) / nickel oxide (NiO) composite catalyst. This better ensures the reaction generation effect).

[0018] In the above steps, the proportion of each reaction component can be increased or decreased in equal proportion. During the preparation process, rhodium nitrate and nickel nitrate will decompose into rhodium trioxide and nickel oxide at high temperature, and the reaction equation is: Rh(NO3)2 → Rh2O3 +NO2 + O2, Ni(NO3)2 → NiO + NO2 + O2. At the same time, the Rh2O3 and NiO produced after decomposition will be embedded in the activated carbon at high temperature to form a composite catalyst of biomass activated carbon loaded with Rh2O3 / NiO, that is, the carbon dioxide catalytic decomposition material, and the reaction equation is: Rh2O3 + NiO + C n →···C···Rh2O3···C···NiO···C···.

[0019] Therefore, the above reaction process can quickly and efficiently produce a carbon dioxide catalytic decomposition material with the main effective components of biomass activated carbon / Rh2O3 / NiO accounting for more than 50%, ensuring the efficient catalytic decomposition effect of carbon dioxide after adsorption. At the same time, the other phase components generated are evenly mixed and doped together, which can help improve the effect of the decomposition reaction and better ensure the durability of the carbon dioxide catalytic treatment effect.

[0020] Furthermore, the biomass carbon-based substrate was prepared by the following method: first, 50 g of rice husk-based biomass powder / lumps were weighed, dissolved in 500 ml of ultrapure water and placed in a sealed reactor, and heated continuously at 150 °C for 24 h; then, the suspension after hydrothermal treatment was filtered through a 0.22 μm microporous filter membrane, and the resulting filter residue was rinsed with ultrapure water for three times, dried in a drying oven at 50 °C for 72 h to obtain agglomerates, and then ground into 200 mesh powder; then, the obtained biomass powder was placed in a muffle furnace and calcined at 500 °C for 3 h under argon (Ar) protection (the heating rate from room temperature to 500 °C was 25 °C / min), and then cooled to room temperature by natural ventilation; the calcined powder was placed in 50 ml of sodium hydroxide solution (50 wt.%) and immersed for 1 h to form a paste, and the paste was placed in a muffle furnace and calcined at 500 °C for 6 h under a conventional air atmosphere. h (the heating rate from room temperature to 500 °C is 20 °C / min), cooled to room temperature by natural ventilation, and then ground into 200 mesh to obtain a porous activated carbon substrate.

[0021] In this way, rice husk is used as the material for preparing biomass carbon. The powder is treated with hydrothermal water, then washed, filtered and evaporated to complete the initial removal of non-carbonized components. Then, carbonization is completed after two grinding and calcination treatments, so that the prepared pure bamboo-based biomass activated carbon can have a higher adsorption efficiency. The rice husk-based biomass powder / lump is converted into porous activated carbon (average pore size 5 nm, average specific surface area>1500 m2 / g), the reaction equation is: C (inactive) → C (porous activated carbon). Therefore, it has the characteristics of low cost, easy preparation, good product porosity and large specific surface area.

[0022] Therefore, the present invention can achieve the process of decomposing carbon dioxide and converting it into carbon monoxide more efficiently and stably, making it more conducive to large-scale production and preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the principle process of the catalytic decomposition of carbon dioxide by the carbon dioxide catalytic decomposition material of the present invention.

[0024] Figure 2 It is a comparative diagram of the Faraday efficiency of the decomposition treatment of the carbon dioxide catalytic decomposition material of the present invention and other types of carbon dioxide catalytic decomposition materials.

[0025] Figure 3 It is a schematic diagram comparing the Faraday efficiency loss of the carbon dioxide catalytic decomposition material of the present invention and other types of carbon dioxide catalytic decomposition materials. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific implementation modes.

[0027] Embodiment: A catalytic conversion method for decomposing carbon dioxide into carbon monoxide, characterized in that it comprises the following steps: In the first step, carbon dioxide molecules and added hydrogen molecules are adsorbed on the surface of biomass activated carbon / Rh2O3 / NiO phase material to form an adsorbed structure, hydrogen molecules are decomposed into adsorbed hydrogen atoms, and carbon dioxide reacts with some hydrogen atoms to generate carboxyl groups; the reaction process includes the following reaction formula: CO2(free) + Rh2O3 / NiO@C → CO2(ad), H2(free) + Rh2O3 / NiO@C → 2*H (ad), CO2 (ad) + *H (ad) → COOH (ad); In the second step, the generated adsorbed carboxyl group reacts with the remaining hydrogen atom to release a water molecule to form an adsorbed carbon monoxide molecule, and the adsorbed carbon monoxide is desorbed to a free state at a high reaction temperature to obtain carbon monoxide gas; the reaction process includes the following reaction formula: COOH (ad) + *H (ad) → CO (ad) + H2O, CO(ad) + energy → CO(free).

[0028] In implementation, the biomass activated carbon is rice husk-based biomass activated carbon. It is easy to prepare and has better porosity, with an average specific surface area of ​​>1500 m 2 / g.

[0029] Thus, the present invention uses biomass activated carbon embedded with Rh2O3 and NiO as a catalytic conversion decomposition material for carbon dioxide decomposition, and can quickly and efficiently decompose carbon dioxide through the above reaction process. In this process, firstly, the biomass activated carbon has a large specific surface area (as mentioned above, the average specific surface area> 1500 m 2 / g), which can provide a large number of adsorption sites for the adsorption of carbon dioxide and hydrogen molecules; secondly, the functional components Rh2O3 and NiO embedded in activated carbon can be used to catalyze the formation of carboxyl groups and catalyze the formation of water molecules, respectively. The synergistic cooperation of the two can greatly increase the efficiency of the catalytic conversion of carbon dioxide into carbon monoxide.

[0030] In specific implementation, a carbon dioxide catalytic decomposition material whose main effective components are biomass activated carbon / Rh2O3 / NiO phase is used to achieve catalytic decomposition treatment of carbon dioxide.

[0031] In the above-mentioned carbon dioxide catalytic decomposition materials, biomass activated carbon serves as a matrix for loading effective ingredients Rh2O3 and NiO and capturing and adsorbing carbon dioxide and hydrogen molecules, and is the base bed for the catalytic reaction. The specific reaction process principle is as follows.

[0032] (a) The role of Rh2O3. For the step of hydrogenating carbon dioxide to form a carboxyl group in the basic process of catalytic conversion of carbon dioxide to carbon monoxide, one of the bonds in the C=O double bond needs to be broken, and then the O atom forms a bond with the adsorbed H atom. Since the Rh atom in Rh2O3 has an active electron in the outer layer, it can form a bond with an active electron in the outer layer of C in CO2, thereby promoting the breaking of a single bond in the above C=O double bond. At the same time, a more basic role is that there are unpaired electrons in the four orbits of the outer layer of the Rh atom, and the probability and intensity of its attraction-bonding effect on the adsorbed H atom are high, which can easily form multiple Rh(Rh2O3)-O(CO2) valence bonds, further enhancing the partial breaking of the C=O double bond. In addition, the supplementary promoting effect is that part of CO2 can be directly adsorbed on the O atom in Rh2O3, and then the C atom can directly bond with this O atom, thereby reducing a C=O double bond to a CO single bond for subsequent bonding with the adsorbed H atom.

[0033] (b) The role of NiO. For the carboxyl hydrogenation and dehydration formation step in the above-mentioned basic process of catalytic conversion of carbon dioxide to carbon monoxide, it requires the hydroxyl group to break off from the carboxyl group and combine with another adsorbed H atom. This process involves the breaking of the CO bond. Since the outer layer of the Ni atom in NiO has 5 active valence electrons, it can migrate across the entire surface through the delocalized π bonds on the porous carbon surface. When it migrates to the carboxyl group, it can combine with the O atom in -OH to form a free radical form, thereby destroying the CO bond and quickly combining with another adsorbed H atom. At the same time, a more basic role is that the H atom formed after the decomposition of the hydrogen molecule is more easily adsorbed on the O atom in NiO. This is because there are still 3 valence electrons on the Ni surface in NiO, which can form a Ni···H structure with the H atom, which can significantly fix the free H atoms and attract the H atoms originally dispersed at different sites on the porous activated carbon surface to gather around the NiO group, further increasing the rate of the carboxyl hydrogenation and dehydration reaction. It should be noted that the Rh2O3 group also has the above-mentioned function of combining with H atoms of NiO, but because Rh in Rh2O3 has only one outer active valence electron left, its ability to aggregate adsorbed H atoms is lower than that of NiO, and it does not serve as the main functional component of the carboxyl hydrogenation and dehydration step.

[0034] Therefore, the present invention can be used for the industrial production of carbon dioxide decomposition and conversion of carbon monoxide, and the carbon dioxide and hydrogen passing through can be quickly catalytically decomposed into carbon monoxide and water under the action of the catalyst, reducing the harm of carbon dioxide emissions to the environment and turning waste into treasure; it can improve the efficiency of carbon dioxide catalytic decomposition. The applicant has verified that the present invention can increase the Faraday efficiency of carbon monoxide generation from 80% to 95%+; and make the Faraday efficiency loss less than 5% after 6 hours of catalytic conversion of carbon dioxide.

[0035] Among them, the carbon dioxide catalytic decomposition material used in the present invention includes the following phase components in the following mass proportions: 0.01-0.15 parts of biomass activated carbon phase, 0.01-0.08 parts of Rh2O3 phase, 0.01-0.11 parts of NiO phase, and 0.66-0.097 parts of biomass activated carbon / Rh2O3 / NiO phase.

[0036] The better mass ratio is: 0.02 parts of biomass activated carbon phase, 0.08 parts of Rh2O3 phase, 0.11 parts of NiO phase, and 0.79 parts of biomass activated carbon / Rh2O3 / NiO phase.

[0037] Among the above-mentioned carbon dioxide catalytic decomposition materials, the biomass activated carbon / Rh2O3 / NiO phase is the main site for the carbon dioxide catalytic decomposition reaction and therefore accounts for a relatively large proportion. The biomass activated carbon phase, Rh2O3 phase and NiO phase are common reaction products and can also be used to provide reaction sites and assist in enhancing the carbon dioxide catalytic decomposition process. Moreover, the components of each phase can have a certain dynamic conversion and supplement effect, thereby better ensuring the durability of the treatment effect.

[0038] During implementation, the carbon dioxide catalytic decomposition material is prepared by the following steps: Step 1: First obtain biomass activated carbon as a substrate; Step 2: Complete the generation and loading of rhodium trioxide and nickel oxide; pour 20 g of the above biomass activated carbon into 500 ml of ultrapure water, and add 0.25 mol of dihydrated rhodium nitrate (Rh(NO3)3·2H2O) and 0.15 mol of hexahydrated nickel nitrate (Ni(NO3)2·6H2O) to form a mixed solution; then, place the obtained mixed solution in a magnetic stirrer and stir and mix continuously at 200 r / min and 50 °C for 2 h; then, place the mixed solution in an oven, evaporate all water at 70 °C to obtain agglomerates, and grind the agglomerates into 200 mesh powder; then, place the above 200 mesh powder in a muffle furnace and calcine continuously at 850 °C for 5 h (the heating rate from room temperature to 500 °C is 50 ℃ / min), and then cooled to room temperature by natural ventilation to obtain a porous activated carbon-supported rhodium trioxide (Rh2O3) / nickel oxide (NiO) composite catalyst (i.e., "Rh2O3 / NiO@C").

[0039] In the above steps, the proportion of each reaction component can be increased or decreased in equal proportion. During the preparation process, rhodium nitrate and nickel nitrate will decompose into rhodium trioxide and nickel oxide at high temperature, and the reaction equation is: Rh(NO3)2 → Rh2O3 +NO2 + O2, Ni(NO3)2 → NiO + NO2 + O2. At the same time, the Rh2O3 and NiO produced after decomposition will be embedded in the activated carbon at high temperature to form a composite catalyst of biomass activated carbon loaded with Rh2O3 / NiO, that is, the carbon dioxide catalytic decomposition material, and the reaction equation is: Rh2O3 + NiO + C n →···C···Rh2O3···C···NiO···C···.

[0040] Therefore, the above reaction process can quickly and efficiently produce a carbon dioxide catalytic decomposition material with the main effective components of biomass activated carbon / Rh2O3 / NiO accounting for more than 50%, ensuring the efficient catalytic decomposition effect of carbon dioxide after adsorption. At the same time, the other phase components generated are evenly mixed and doped together, which can help improve the effect of the decomposition reaction and better ensure the durability of the carbon dioxide catalytic treatment effect.

[0041] During implementation, the biomass carbon-based substrate was prepared by the following method: first, 50 g of rice husk-based biomass powder / lumps were weighed, dissolved in 500 ml of ultrapure water and placed in a sealed reactor, and heated continuously at 150 °C for 24 h; then, the suspension after hydrothermal treatment was filtered through a 0.22 μm microporous filter membrane, and the resulting filter residue was rinsed with ultrapure water for three times, dried in a drying oven at 50 °C for 72 h to obtain agglomerates, and then ground into 200 mesh powder; then, the obtained biomass powder was placed in a muffle furnace and calcined at 500 °C for 3 h under argon (Ar) protection (the heating rate from room temperature to 500 °C was 25 °C / min), and then cooled to room temperature by natural ventilation; the calcined powder was placed in 50 ml of sodium hydroxide solution (50 wt.%) and immersed for 1 h to form a paste, and the paste was placed in a muffle furnace and calcined at 500 °C for 6 h under a conventional air atmosphere. h (the heating rate from room temperature to 500 °C is 20 °C / min), cooled to room temperature by natural ventilation, and then ground into 200 mesh to obtain a porous activated carbon substrate.

[0042] In this way, rice husk is used as the material for preparing biomass carbon. The powder is treated with hydrothermal water, then washed, filtered and evaporated to complete the initial removal of non-carbonized components. Then, carbonization is completed after two grinding and calcination treatments, so that the prepared pure bamboo-based biomass activated carbon can have a higher adsorption efficiency. The rice husk-based biomass powder / lump is converted into porous activated carbon (average pore size 5 nm, average specific surface area>1500 m 2 / g), the reaction equation is: C (inactive) → C (porous activated carbon). Therefore, it has the characteristics of low cost, easy preparation, good product porosity and large specific surface area.

[0043] In order to better verify the effect of the present invention, the applicant conducted a comparative test, using the carbon dioxide catalytic decomposition material obtained in the above specific embodiment as the experimental group, and using other carbon dioxide catalytic decomposition materials as the comparative group, and conducted catalytic conversion efficiency comparison tests and conversion efficiency loss degree comparisons, and the test results are shown in Figure 2 and Figure 3 .

[0044] for Figure 2, under the environmental conditions of 300 ℃ / 3.5 MPa / 0% relative humidity, Pd-loaded Ag, AuCu, AuCuB, and NiMn were used as control group catalysts, and the molar contents of hydrogen (reaction gas) and nitrogen (carrier gas) were set to 76% and 5%, respectively, to compare the efficiency of 19% carbon dioxide hydrogenation catalytic conversion to carbon monoxide. From the experimental results, it can be seen that the carbon monoxide conversion efficiency of the above control group catalysts is lower than that of the rice husk-based activated carbon-loaded Rh2O3 / NiO catalyst, especially the carbon monoxide conversion efficiency of the rice husk-based activated carbon-loaded Rh2O3 / NiO is much higher than that of AuCu, indicating that the coexistence of Rh2O3 and NiO can make the surface of rice husk-based activated carbon catalyze carbon dioxide to have a synergistic effect, greatly enhancing the catalytic conversion ability of this type of composite catalyst.

[0045] for Figure 3 , under the environmental conditions of 300 ℃ / 3.5 MPa / 0% relative humidity, Pd-loaded Ag and AuCu were used as control catalysts, and the molar contents of hydrogen (reaction gas) and nitrogen (carrier gas) were set to 76% and 5%, respectively, to compare the 6h conversion efficiency loss of carbon dioxide hydrogenation catalytic conversion to carbon monoxide with a molar content of 19%. From the experimental results, it can be seen that the 6h conversion efficiency loss of the above Pd-loaded Ag is higher than that of the rice husk-based activated carbon-loaded Rh2O3 / NiO catalyst, indicating that the coexistence of Rh2O3 and NiO can make the surface of rice husk-based activated carbon catalyze carbon dioxide to have a synergistic effect, greatly weakening the loss of the catalytic conversion ability of this type of composite catalyst.

Claims

1. A catalytic conversion method for decomposing carbon dioxide into carbon monoxide, characterized in that: The following steps are involved: In the first step, carbon dioxide molecules and added hydrogen molecules are adsorbed on the surface of biomass activated carbon / Rh2O3 / NiO phase material to form an adsorbed structure, hydrogen molecules are decomposed into adsorbed hydrogen atoms, and carbon dioxide reacts with some hydrogen atoms to generate carboxyl groups; The reaction process includes the following reaction formula: CO2(free) + Rh2O3 / NiO@C → CO2(ad), H2(free) + Rh2O3 / NiO@C → 2*H (ad), CO2 (ad) + *H (ad) → COOH (ad); In the second step, the generated adsorbed carboxyl group reacts with the remaining hydrogen atom to release a water molecule to form an adsorbed carbon monoxide molecule, and the adsorbed carbon monoxide is desorbed to a free state at a high reaction temperature to obtain carbon monoxide gas; the reaction process includes the following reaction formula: COOH (ad) + *H (ad) → CO (ad) + H2O, CO(ad) + energy → CO(free).

2. The catalytic conversion method for decomposing carbon dioxide into carbon monoxide according to claim 1, characterized in that: In this method, a carbon dioxide catalytic decomposition material whose main effective components are biomass activated carbon / Rh2O3 / NiO phase is used to achieve catalytic decomposition treatment of carbon dioxide.

3. The catalytic conversion method for decomposing carbon dioxide into carbon monoxide according to claim 2, characterized in that: The carbon dioxide catalytic decomposition material used in the present invention comprises the following phase components in the following mass proportions: 0.01-0.15 parts of biomass activated carbon phase, 0.01-0.08 parts of Rh2O3 phase, 0.01-0.11 parts of NiO phase, and 0.66-0.097 parts of biomass activated carbon / Rh2O3 / NiO phase.

4. The catalytic conversion method for decomposing carbon dioxide into carbon monoxide according to claim 3, characterized in that: The carbon dioxide catalytic decomposition material used in the present invention includes the following phase components in the following mass proportions: 0.02 parts of biomass activated carbon phase, 0.08 parts of Rh2O3 phase, 0.11 parts of NiO phase, and 0.79 parts of biomass activated carbon / Rh2O3 / NiO phase.

5. The catalytic conversion method for decomposing carbon dioxide into carbon monoxide according to claim 3, characterized in that: The carbon dioxide catalytic decomposition material is prepared by the following steps: Step 1: First obtain biomass activated carbon as a substrate; Step 2: Complete the generation and loading of rhodium trioxide and nickel oxide; pour 20 g of the above-mentioned biomass activated carbon into 500 ml of ultrapure water, and add 0.25 mol of rhodium nitrate dihydrate and 0.15 mol of nickel nitrate hexahydrate to form a mixed solution; then, stir the obtained mixed solution evenly, dry it and grind it into powder; then, calcine the obtained powder to obtain a porous activated carbon-loaded rhodium trioxide / nickel oxide composite catalyst.

6. The catalytic conversion method for decomposing carbon dioxide into carbon monoxide according to claim 5, characterized in that: In step 2, the drying and grinding process is to place the mixture in a magnetic stirrer and stir it continuously at 200 r / min and 50°C for 2 h; then, place the mixed solution in an oven to evaporate all water at 70°C to obtain agglomerates, and grind the agglomerates into 200 mesh powder.

7. The catalytic conversion method for decomposing carbon dioxide into carbon monoxide according to claim 5, characterized in that: In step 2, the calcination process is as follows: placing a 200-mesh powder in a muffle furnace, calcining continuously at 850 °C for 5 h, heating from room temperature to 500 °C at a rate of 50 °C / min before calcination, and then cooling to room temperature by natural ventilation to obtain a porous activated carbon-supported rhodium trioxide / nickel oxide composite catalyst.

8. The catalytic conversion method for decomposing carbon dioxide into carbon monoxide according to claim 5, characterized in that: In step 1, the biomass carbon-based substrate is prepared by the following method: first, 50 g of rice husk-based biomass powder / lump is weighed, dissolved in 500 ml of ultrapure water and placed in a sealed reactor, and continuously heated at 150 ° C for 24 h; then, the suspension after hydrothermal treatment is filtered through a 0.22 μm microporous filter membrane, and the obtained filter residue is continuously rinsed with ultrapure water for 3 times, and continuously dried in a drying oven at 50 ° C for 72 h to obtain agglomerates, and then ground into 200 mesh powder; then, the obtained biomass powder is placed in a muffle furnace and calcined at 500 ° C for 3 h under argon protection, and the heating rate from room temperature to 500 ° C before calcination is 25 ° C / min, and then naturally ventilated to room temperature; the calcined powder is placed in 50 ml of sodium hydroxide solution and immersed for 1 h to form a slurry, and the slurry is placed in a muffle furnace and calcined at 500 ° C for 6 h in a conventional air atmosphere. h, the heating rate from room temperature to 500 °C before calcination was 20 °C / min, and the porous activated carbon substrate was obtained after being cooled to room temperature by natural ventilation and then ground to 200 mesh.

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