CN-117963975-B - Porous indium oxide catalyst and preparation method and application thereof

Abstract

The invention provides a porous indium oxide catalyst and a preparation method and application thereof, and solves the technical problems that a plurality of catalysts are used in the existing preparation of methanol by activating carbon dioxide and hydrogen step by step, a catalyst system is complex, and the preparation process is complex. According to the preparation method, firstly, a cubic In (OH) 3 precursor with uniform morphology is prepared by a simple one-step hydrothermal method and well controlling the reaction temperature and the reaction time by the hydrothermal method In a strong alkali environment, and then, the precursor is calcined and oxidized In an air atmosphere to convert In (OH) 3 into a stable porous cubic structure In 2 O 3 .

Inventors

• ZHANG SAI
• WANG YOU

Assignees

• 西北工业大学深圳研究院

Dates

Publication Date

20260508

Application Date

20240130

Claims (6)

1. 1. The application of the porous indium oxide with the cubic structure morphology in preparing methanol by activating carbon dioxide and hydrogen step by step is characterized in that the step activation refers to that the porous indium oxide with the cubic structure morphology is used as a catalyst to prepare dimethyl carbonate by using the carbon dioxide and the methanol, and the porous indium oxide with the cubic structure morphology is used as the catalyst to hydrogenate the dimethyl carbonate to prepare the methanol, wherein the preparation method of the porous indium oxide with the cubic structure morphology comprises the following steps: 1) In (OH) 3 precursor is prepared by a hydrothermal method by dropwise adding a solution prepared from In (NO 3 ) 3 ·5H 2 O and ultrapure water) into a strong alkali solution; The molar concentration of OH - in the reaction solution is 6M-9M; 2) And (3) placing the In (OH) 3 precursor obtained In the step 1) In an air atmosphere, and calcining at the temperature of 250-350 ℃ for 2-4 hours to obtain the porous indium oxide with the cubic structure morphology.
2. 2. The use according to claim 1, wherein step 1) is specifically: Slowly adding NaOH into a polytetrafluoroethylene liner filled with ultrapure water, stirring, slowly dropwise adding a solution prepared from In (NO 3 ) 3 ·5H 2 O and ultrapure water after the NaOH solution is cooled, stirring at room temperature after the dropwise adding is completed, placing into a reaction kettle, reacting 12-24 h at 100 o C ~ 120 o C, alternately washing with water and alcohol for a plurality of times after the reaction is finished, and then drying 8-12 h at 60 o C ~ 80 o C to obtain an In (OH) 3 precursor.
3. 3. The use according to claim 2, characterized in that: in step 1), the concentration of NaOH in the reaction solution was 6M.
4. 4. A use according to claim 3, characterized in that: In the step 2), the In (OH) 3 precursor obtained In the step 1) is placed In a muffle furnace, calcined for 2 hours at the temperature rising rate of 5 o C/min In the air atmosphere, and naturally cooled to obtain the porous indium oxide with the cubic structure morphology.
5. 5. The method for preparing the dimethyl carbonate by using the carbon dioxide and the methanol is characterized by comprising the following steps of: Uniformly dispersing the porous indium oxide with the cubic structure morphology according to any one of claims 1-4 in absolute methanol, transferring the absolute methanol into a high-pressure reaction kettle, and filling CO 2 not lower than 1 MPa for reaction at a reaction temperature of 70 o C ~ 100 o C to obtain the dimethyl carbonate after the reaction is completed.
6. 6. The method for preparing methanol by using dimethyl carbonate and hydrogen is characterized by comprising the following steps: Uniformly dispersing the porous indium oxide with the cubic structure morphology according to any one of claims 1-4 in dimethyl carbonate solution, transferring the solution into a high-pressure reaction kettle, filling H 2 not lower than 2MPa for reaction, and obtaining methanol after the reaction is completed at a reaction temperature of 70 o C ~ 100 o ℃.

Description

Porous indium oxide catalyst and preparation method and application thereof Technical Field The invention belongs to the technical field of thermocatalysis, and particularly relates to a porous indium oxide catalyst and a preparation method and application thereof. Background At present, methanol is mainly prepared by hydrogenation of carbon dioxide, and the catalyst is mainly Cu/ZnO/Al 2O3, however, the catalyst system has more defects, such as reaction under the condition of high temperature and high pressure, difficult reaction conditions are easy to initiate reverse water gas reaction, CO and H 2 O byproducts are generated to cause active center deactivation and ZnO agglomeration. The method for preparing the methanol by activating the carbon dioxide and the hydrogen step by step is a common process at present, and although the method can avoid high-temperature reaction conditions (because the carbon dioxide is easy to generate carbonate compounds), the method still needs to be faced with the problems of high-pressure reaction conditions, complex catalyst preparation process and difficulty in realizing the simultaneous activation of two molecules by one catalyst, for example, zirconium dioxide or cerium dioxide catalyst is used for preparing the dimethyl carbonate by the carbon dioxide and the methanol, and Cu (x)/CeO2 catalyst is used for realizing the hydrogenation of organic carbonate (dimethyl carbonate) to prepare the methanol, and two different catalysts are needed to catalyze different reaction systems in the step activation flow. Therefore, in the heterogeneous catalytic reaction, the design and synthesis of the catalyst plays a role in playing important roles in the reaction conditions and the catalytic performance in the reaction, however, most of the existing catalysts are as good as the current situation, the application value of one-to-many is difficult to realize, and the problems of complex catalytic system and complex catalyst preparation process exist. In view of the current situation, the application is intended to be designed integrally for catalysts used in the stepwise activation of carbon dioxide and hydrogen to produce methanol. Disclosure of Invention The invention aims to solve the technical problems that a plurality of catalysts are used in the existing step-by-step activation of carbon dioxide and hydrogen to prepare methanol, a catalyst system is complex and a preparation process is complex, and provides a porous indium oxide catalyst and a preparation method and application thereof. The conception of the invention: Because the reaction conditions of the step-by-step activation process are milder, the research team of the invention aims at the step-by-step activation process, and aims to design a catalyst which can be shared in the step-by-step activation process, and the design of the catalyst for preparing the dimethyl carbonate by carbon dioxide and methanol is considered to meet the following points that 1) CO 2 and CH 3 OH can be adsorbed and activated to be converted into corresponding active intermediates, 2) other metals cannot be loaded, and the problems of competitive adsorption of two molecules and deactivation of oxygen vacancies of the catalyst are avoided. In the design of a catalyst for preparing methanol from dimethyl carbonate and hydrogen, the following points need to be met, namely 1) steric hindrance when oxygen in the dimethyl carbonate is inserted into an oxygen vacancy of the catalyst, and 2) whether an activation site of the hydrogen influences the adsorption of the dimethyl carbonate or not, and further influence the further activation. Therefore, the research team combines the design requirement of the catalyst for preparing the methyl carbonate from the carbon dioxide and the methanol and preparing the methyl carbonate from the hydrogen and the bottleneck at present, in 2O3 with controllable oxygen vacancies is adopted as a catalyst shared In the step-by-step activation, the unique oxygen vacancies can be used as active sites for activating small molecules such as H 2、CO2、CH4, and the like, and the optimization of the active sites can be realized by optimizing the number of the oxygen vacancies, so that the performance is improved. However, the morphology of most In 2O3 is difficult to control at present, which prevents the existing In 2O3 from being directly utilized, and the regular preparation process of In 2O3 is complicated, or oleylamine and the like are additionally added, so that the sample post-treatment process is complicated, partial impurities remain, and the catalytic activity and the structure of In 2O3 are difficult to form a structure-activity relationship. Therefore, the research team optimizes the preparation process of In 2O3 to prepare the porous cubic structure In 2O3 catalyst (PC-In 2O3), and realizes the regulation and control of In 2O3 oxygen vacancies through the reaction environment regulation and the calcination temperatur