A Ni / In₂O₃ catalyst for methanol synthesis reaction, its preparation method and application

Abstract

This invention relates to the field of catalysis technology, and in particular to a Ni / In₂O₃ catalyst for catalytic methanol synthesis, its preparation method, and its application. This invention is the first to synthesize morphologically stable rod-shaped, hollow rod-shaped, and sheet-shaped Ni / In₂O₃ catalysts. By controlling the morphology of the In₂O₃ support and then subjecting the In₂O₃ support to Ni loading, the resulting Ni / In₂O₃ catalyst exhibits stable morphology and good catalytic performance. This invention is the first to apply morphology control to the preparation of In₂O₃ catalysts, and simultaneously utilizes an impregnation method to cleverly load Ni onto the In₂O₃ catalyst. The two technologies are cleverly combined, and their synergistic effect positively impacts the catalyst's performance.

Description

Technical Field

[0001] This invention relates to the field of catalysis technology, and in particular to a Ni / In2O3 catalyst for catalyzing methanol synthesis, its preparation method, and its application. Background Technology

[0002] Methanol is a globally used chemical product, commonly used as a chemical raw material. It is also a clean fuel, usable alone or blended with gasoline as automotive fuel. As an excellent liquid fuel, methanol offers convenient energy storage for transportation and fuel cells. Data shows that methanol demand was approximately 80-90 million tons in 2018, and is projected to exceed 110 million tons by 2023. With the massive consumption of fossil fuels and increased CO2 emissions in recent years, the capture, recovery, utilization, and storage of CO2 to produce alternative fuels has become a research hotspot. Researchers hope to effectively address these issues by producing methanol through the catalytic hydrogenation of CO2.

[0003] Currently, the most widely studied catalyst for CO2 hydrogenation to methanol is Cu / ZnO / Al2O3. This catalyst has been industrially applied for decades in the production of methanol from syngas (CO2, CO, and H2). In recent years, it has been used in CO2 hydrogenation reactions, but the catalyst is prone to deactivation in the presence of water, resulting in poor stability. Furthermore, research and exploration of catalysts for CO2 hydrogenation to methanol have attracted significant attention under the "dual-carbon" vision. In2O3 catalysts exhibit high selectivity in CO2 hydrogenation to methanol and maintain structural stability before and after the reaction, making them highly valuable. However, their CO2 conversion rate is low. Ni, on the other hand, is abundant and readily available. Therefore, Ni-modified In2O3 catalysts are used to obtain more active Ni / In2O3. Studying the catalytic activity of In2O3 catalysts with different morphologies after Ni loading, and obtaining Ni / In2O3 catalysts with higher methanol space-time yields, provides theoretical support for future industrial applications and has significant scientific implications. Summary of the Invention

[0004] To address the shortcomings of current technologies, the present invention aims to provide three Ni / In2O3 catalysts for methanol synthesis, their preparation methods, and applications. The activity of Ni catalysts with different In2O3 morphologies for catalytic methanol production was also investigated.

[0005] A Ni / In2O3 catalyst for catalyzing methanol synthesis reaction, wherein the catalyst is an indium oxide supported Ni catalyst with metallic nickel as a promoter, and the oxygen vacancies on the indium oxide are the active phase, and its morphology is rod-shaped, hollow rod-shaped or sheet-shaped.

[0006] Another technical solution provided by this invention is a method for preparing the above-mentioned Ni / In2O3 catalysts with different morphologies through a hydrothermal-impregnation method, specifically as follows:

[0007] A method for preparing a Ni / In₂O₃ catalyst for catalyzing methanol synthesis includes the following steps:

[0008] (I): Preparation of rod-shaped support c-In2O3-r:

[0009] (1-1) Add urea to the aqueous solution of indium compound, mix and stir evenly, place in a hydrothermal reactor, keep at 100-130℃ for 6-24h (preferably keep at 130℃ for 12h), cool to room temperature, centrifuge, wash, and dry at 60-80℃ for 12-24h (preferably dry at 80℃ for 24h), the molar ratio of indium compound to urea in the aqueous solution of indium compound is 1:(8-10), preferably 1:10;

[0010] (1-2) After the solid dried in step (1-1) is calcined at 300-350℃ for 2-5 hours (preferably calcined at 350℃ for 3 hours), rod-shaped support c-In2O3-r is obtained;

[0011] (II) Preparation of Ni / In2O3 catalyst

[0012] A soluble nickel solution is impregnated onto the support c-In2O3-r prepared in step (I). The impregnated material is then dried by vacuum distillation for 10-36 hours (preferably at 100°C for 12 hours) and then calcined at 300-700°C for 1-10 hours (preferably at 450°C for 4 hours) to obtain a Ni / In2O3 catalyst in rod form.

[0013] Furthermore, the support c-In2O3-r described in step (i) of the above preparation method can be replaced with the hollow rod-shaped support c-In2O3-h prepared in step (2) below to prepare a hollow rod-shaped catalyst:

[0014] (2): Preparation of hollow rod-shaped support c-In2O3-h:

[0015] (2-1) Take indium compound, terephthalic acid and N,N-dimethylformamide, mix them, and then ultrasonically stir until fully dissolved. Place them in a hydrothermal reactor and keep them at 100-130℃ for 6-24h (preferably at 100℃ for 24h). After cooling to room temperature, centrifuge and wash them. Then dry them at 60-80℃ for 12-24h (preferably at 60℃ for 12h) and then vacuum dry them at 120-150℃ for 2-4h (preferably at 150℃ for 2h). The molar ratio of indium compound to terephthalic acid is 1:(0.8-1.3), preferably 1:1.

[0016] (2-2) After the solid dried in step (2-1) is calcined at 500-700℃ for 1-4h (preferably at 600℃ for 2h), hollow rod-shaped support c-In2O3-h is obtained;

[0017] Using this support, a hollow rod-shaped Ni / In2O3 catalyst was synthesized after step (II).

[0018] Furthermore, the support c-In2O3-r described in step (ii) of the above preparation method can be replaced with the sheet-like support c-In2O3-p prepared in step (3) below to prepare a sheet-like catalyst:

[0019] (3): Preparation of the sheet-like support c-In2O3-p:

[0020] (3-1) After stirring and mixing the indium compound aqueous solution and the urea aqueous solution evenly, place them in a hydrothermal reactor and keep them at 100-130℃ for 6-24h (preferably at 120℃ for 17h). After cooling to room temperature, centrifuge and wash them, and then dry them at 60-80℃ for 12-24h (preferably at 60℃ for 12h). The molar ratio of indium compound in the indium compound aqueous solution to urea in the urea aqueous solution is 1:(6-9), preferably 1:7.

[0021] (3-2) After the solid dried in step (3-1) is calcined at 300-350℃ for 2-5 hours (preferably calcined at 300℃ for 5 hours), a sheet-like support c-In2O3-p is obtained;

[0022] Using this support, a sheet-like Ni / In2O3 catalyst was synthesized after step (II).

[0023] The indium compound is indium chloride tetrahydrate or indium nitrate hydrate.

[0024] Furthermore, the specific surface area S of the Ni / In2O3 catalyst BET 20-50m 2 / g, pore volume V p 0.1-1cm 3 / g, most probable aperture DBJH It is 2-20nm.

[0025] Furthermore, in step (ii), the Ni content in the Ni / In2O3 catalyst is 1 wt%.

[0026] This invention also provides the application of the above-mentioned Ni / In2O3 catalyst in the methanol synthesis reaction.

[0027] The present invention also provides the application of the catalyst prepared by the above method in the methanol synthesis reaction.

[0028] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0029] This invention is the first to synthesize morphologically stable rod-shaped, hollow rod-shaped, and sheet-shaped Ni / In₂O₃ catalysts. Currently, most known catalysts in the literature are spherical with fixed and uniform morphologies. By controlling the morphology of the In₂O₃ support and then treating the In₂O₃ support with Ni, the resulting Ni / In₂O₃ catalyst exhibits stable morphology and a larger pore volume compared to spherical catalysts, thus resulting in better catalytic performance. Furthermore, it demonstrates a significant improvement over the methanol synthesis catalytic effect of In₂O₃.

[0030] The catalyst prepared in this invention has a wide range of readily available and inexpensive Ni sources, and the reaction process is simple and environmentally friendly.

[0031] This invention is the first to apply morphology control to the preparation of In₂O₃ catalysts. Simultaneously, it cleverly combines Ni with an impregnation method to support Ni on the In₂O₃ catalyst. The two techniques work synergistically (the hydrothermal method effectively controls morphology, while the impregnation method minimizes metal loss during loading), positively impacting catalyst performance. The hydrothermal-impregnation method stabilizes the catalyst morphology, and Ni / In₂O₃ catalysts with different morphologies exhibit different defect oxygen (O₂) characteristics. defect The content of ) leads to different CO2 conversion rates of the catalyst, which in turn leads to different space-time yields of methanol. By comparing the catalytic mechanism of methanol synthesis reaction on Ni / In2O3 catalysts with different morphologies, we can promote the development of catalyst design at the molecular level. Attached Figure Description

[0032] Figure 1 and Figure 2 The images shown are SEM and TEM images of the In2O3 carrier in Examples 1-3, where a is the c-In2O3-r sample, b is the c-In2O3-h sample, and c is the c-In2O3-p sample.

[0033] Figure 3These are TEM images of the Ni / In2O3 catalyst in Examples 1-3. In the images, a is the 1Ni / c-In2O3-r sample, b is the 1Ni / c-In2O3-h sample, and c is the 1Ni / c-In2O3-p sample.

[0034] Figure 4 a is a diagram showing the physical adsorption / desorption of N2 by the In2O3 carrier in Examples 1-3 and its pore size distribution. In the diagram, a is the c-In2O3-r sample, b is the c-In2O3-h sample, and c is the c-In2O3-p sample.

[0035] Figure 4 b is a diagram showing the N2 physical adsorption / desorption of the catalyst Ni / In2O3 in Examples 1-3 and its pore size distribution. In the diagram, a is the 1Ni / c-In2O3-r sample, b is the 1Ni / c-In2O3-h sample, and c is the 1Ni / c-In2O3-p sample.

[0036] Figure 5 The X-ray photoelectron spectra of the catalyst Ni / In2O3 in Examples 1-3 are shown in the figures. In the figures, a is the 1Ni / c-In2O3-r sample, b is the 1Ni / c-In2O3-h sample, and c is the 1Ni / c-In2O3-p sample. Detailed Implementation

[0037] To make the objectives, technical solutions, advantages, and beneficial effects of the present invention clearer, the technical solutions of the present invention will be further described in detail below with reference to specific embodiments.

[0038] In the following examples, the abbreviations for support and catalyst are as follows: r represents rod-like, h represents hollow rod-like, and p represents piece-like. "1" represents controlling the Ni content in the catalyst to 1 wt%, that is, the mass ratio of Ni to Ni / In2O3 catalyst.

[0039] In the following examples, the heating rate of the muffle furnace is set to 5°C / min.

[0040] Example 1

[0041] A method for preparing a 1Ni / c-In2O3-r catalyst for catalyzing methanol synthesis includes the following steps:

[0042] (1)c-In2O3-r:

[0043] (1-1) Add 0.01 mol indium chloride tetrahydrate to 50 ml of distilled water and stir for 10 min. Then add 0.1 mol urea and stir for 15 min until the mixture is homogeneous. Place the mixture in a hydrothermal reactor and heat it to 130 °C. Then keep it at 130 °C for 12 h. After the solution cools to room temperature, centrifuge to collect the solid precipitate. Wash the solid precipitate with anhydrous ethanol and water three times each, and centrifuge to collect the precipitate.

[0044] (1-2) The precipitate collected in (1-1) was dried at 80℃ for 24h and then placed in a muffle furnace and heated to 350℃. It was then calcined at 350℃ for 3h to obtain the support c-In2O3-r.

[0045] (2) Catalyst preparation by equal volume impregnation method: The above-prepared support c-In2O3-r was weighed and just completely wetted with distilled water. Then it was impregnated in a nickel nitrate solution with an equal volume of distilled water. Without filtration, the impregnated material was directly removed by vacuum distillation to remove the water. Then it was dried at 110℃ for 12h and calcined in a muffle furnace at 450℃ for 4h to obtain 1Ni / c-In2O3-r catalyst, wherein the mass ratio of Ni to the catalyst is 1%.

[0046] The aforementioned carrier c-In2O3-r is in powder form, with a specific surface area S BET It is 29.7m 2 / g, most probable pore size D BJH It is 9.8nm, and the pore volume V p It is 0.14cm 3 / g, with an average length of 5.7μm and a diameter of about 740nm, the carrier c-In2O3-r is a long, solid rod with closed ends.

[0047] The final product, 1Ni / c-In2O3-r catalyst, has S BET It is 21.1m 2 / g,D BJH It is 11.1nm, V p 0.12cm 3 The average length of the 1Ni / c-In2O3-r catalyst is 5.3 μm, and the diameter is about 500 nm. Moreover, the catalyst is still a long, solid rod-shaped structure with closed ends.

[0048] The Ni content in the above-mentioned 1Ni / c-In2O3-r catalyst was determined by ICP-MS. The theoretical calculated value was 1 wt%, and the actual measured value was 0.998 wt%.

[0049] The defective oxygen (O) in the above-mentioned product 1Ni / c-In2O3-r catalyst defectThe content was measured by X-ray photoelectron spectroscopy, and the result was 23%.

[0050] Example 2

[0051] A method for preparing a 1Ni / c-In2O3-h catalyst for catalyzing methanol synthesis includes the following steps:

[0052] (1) c-In2O3-h:

[0053] (1-1) Mix 0.007 mol indium chloride tetrahydrate, 0.007 mol terephthalic acid and 25 ml N,N-dimethylformamide, and then sonicate until fully dissolved; place the resulting solution in a hydrothermal reactor and heat to 100°C, and then maintain at 100°C for 24 h; after the solution cools to room temperature, centrifuge to collect the solid precipitate, wash the solid precipitate three times with anhydrous ethanol, and then centrifuge to collect the precipitate;

[0054] (1-2) The precipitate obtained in (1-1) was dried at 60°C for 12 h; then it was vacuum dried at 150°C for 2 h (vacuum degree of 0.09 MPa), placed in a muffle furnace and heated to 600°C, and then calcined at 600°C for 2 h to obtain the support c-In2O3-h.

[0055] (2) Catalyst preparation by equal volume impregnation method: The above-prepared support c-In2O3-h was weighed and just completely wetted with distilled water. Then it was impregnated in a nickel nitrate solution with an equal volume of distilled water. Without filtration, the impregnated material was directly removed by vacuum distillation. Then it was dried at 110℃ for 12h and calcined in a muffle furnace at 450℃ for 4h to obtain 1Ni / c-In2O3-h catalyst, wherein the theoretical mass ratio of Ni to catalyst is 1%.

[0056] The above-mentioned c-In2O3-h support is in powder form, with a specific surface area S BET It is 21.6m 2 / g, most probable pore size D BJH It is 16.5nm, and the pore volume V p It is 0.15cm 3 / g, with an average length of 3μm and a diameter of about 870nm, and the carrier c-In2O3-h is a thin, open-ended rod-shaped hollow structure.

[0057] The final product, 1Ni / c-In2O3-h catalyst, has S BET It is 21.0m 2 / g,D BJH It is 17.4nm, V p It is 0.17cm 3 / g, with an average length of 3.3μm and a diameter of about 810nm, and the carrier c-In2O3-h is a thin, open-ended rod-shaped hollow structure.

[0058] The Ni content in the above-mentioned 1Ni / c-In2O3-h catalyst was determined by ICP-MS. The theoretical calculated value was 1 wt%, and the actual measured value was 0.989 wt%.

[0059] The defect oxygen (O) in the above-mentioned product 1Ni / c-In2O3-h catalyst defect The content was measured by X-ray photoelectron spectroscopy, and the result was 29%.

[0060] Example 3

[0061] A method for preparing a 1Ni / c-In2O3-p catalyst for catalyzing methanol synthesis includes the following steps:

[0062] (1) c-In2O3-p:

[0063] (1-1) First, dissolve 0.01 mol of indium nitrate hydrate uniformly in 32 ml of distilled water; dissolve 0.07 mol of urea in 20 ml of distilled water; mix the two solutions obtained above and stir for 2 h until uniform, then place them in a hydrothermal reactor and heat to 120 °C, and then maintain at 120 °C for 17 h; after the solution cools to room temperature, centrifuge to collect the solid precipitate, wash the obtained solid precipitate with distilled water 3 times each, and then centrifuge to collect the precipitate;

[0064] (1-2) The precipitate obtained in (1-1) was dried at 60℃ for 12h; then heated to 300℃ in a muffle furnace and calcined at 300℃ for 5h to obtain the support c-In2O3-p.

[0065] (2) Catalyst preparation by equal volume impregnation method: The above-prepared support c-In2O3-p was weighed and just completely wetted with distilled water. Then it was impregnated in a nickel nitrate solution with an equal volume of distilled water. Without filtration, the impregnated material was directly removed by vacuum distillation to remove the water. Then it was dried at 110℃ for 12h and calcined in a muffle furnace at 450℃ for 4h to obtain 1Ni / c-In2O3-p catalyst, wherein the mass ratio of Ni to catalyst is 1%.

[0066] The above-mentioned c-In2O3-p support is in powder form, with a specific surface area S BET It is 75.5m 2 / g, most probable pore size D BJH It is 3.8nm, and the pore volume V p It is 0.14cm 3 / g, with a length and width between 70-90nm and a height between 40-50nm.

[0067] The final product, 1Ni / c-In2O3-p catalyst, has S BET 48.6m 2 / g,D BJH It is 5.0nm, V p It is 0.13cm 3 / g, with a length and width between 100-160nm and a height between 60-80nm.

[0068] The Ni content in the above-mentioned 1Ni / c-In2O3-p catalyst was determined by ICP-MS. The theoretical calculated value was 1 wt%, and the actual measured value was 1.03 wt%.

[0069] The defective oxygen (O) in the above-mentioned 1Ni / c-In2O3-p catalyst defect The content was measured by X-ray photoelectron spectroscopy, and the result was 24%.

[0070] Tables 1 and 2 show the pore size distribution data of the In2O3 support and catalyst obtained in Examples 1-3, respectively.

[0071] Table 1

[0072]

[0073] Table 2

[0074]

[0075] The 1Ni / c-In2O3-r, 1Ni / c-In2O3-h, and 1Ni / c-In2O3-p catalysts from Examples 1-3 were applied to the catalytic methanol synthesis reaction. The results are shown in Table 3. It can be seen that 1Ni / c-In2O3-r contains a closed pore structure, thus having a smaller pore volume. 1Ni / c-In2O3-p has a moderate pore volume, while 1Ni / c-In2O3-h has a larger pore volume. The larger pore structure allows more gas molecules to pass through, enabling the catalyst to contact and activate more CO2 and H2 gas molecules, thereby leading to a better methanol space-time yield. Therefore, catalysts with different morphologies exhibit different CO2 conversion rates: 1Ni / c-In2O3-h (14.5%), 1Ni / c-In2O3-p (12.8%), and 1Ni / c-In2O3-r (9.3%). 1Ni / c-In2O3-h demonstrates high CO2 conversion, moderate CO selectivity, and methanol selectivity, ultimately resulting in a higher methanol space-time yield (0.118 g / L). MeOH / gcat The methanol space-time yield was second only to 1Ni / c-In2O3-p (0.097 g / h), with the latter being 0.097 g / h. MeOH / g cat / h), the final methanol space-time yield of 1Ni / c-In2O3-r (0.075 g) MeOH / g cat / h), (see Table 3). The reaction conditions used were: P = 2.0 MPa, GHSV = 3600 h. -1 CO2 / H2 = 3:1 (volume ratio), reaction temperature 300℃.

[0076] Table 3 Catalytic results of methanol synthesis reaction using the catalyst

[0077]

[0078] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. Application of a Ni / In2O3 catalyst in a methanol synthesis reaction, wherein the Ni / In2O3 catalyst is an indium oxide supported Ni catalyst, the metal nickel is used as an additive, oxygen vacancies on the indium oxide are active phases, and the morphology of the indium oxide is a hollow rod shape. The preparation method of the Ni / In2O3 catalyst comprises the following steps: (1) Preparation of a hollow rod-shaped carrier c-In2O3-h: (1-1) mixing indium compound, terephthalic acid and N,N-dimethylformamide, then ultrasonic stirring until fully dissolved, put into hydrothermal kettle, keep at 100-130 °C for 6-24 h, after cooling to room temperature, centrifugation, washing, drying at 60-80 °C for 12-24 h, then vacuum drying at 120-150 °C for 2-4 h, wherein, The molar ratio of the indium compound and terephthalic acid is 1:

1. (1-2) The vacuum-dried solid obtained in step (1-1) is calcined at 500-700 ℃ for 1-4 h to obtain the hollow rod-shaped carrier c-In2O3-h. (2) Preparation of a Ni / In2O3 catalyst A soluble nickel solution is impregnated on the carrier c-In2O3-h prepared in step (1), and the impregnated material is subjected to vacuum distillation to remove water therefrom, then dried at 90-150 ℃ for 10-36 h, and finally calcined at 300-700 ℃ for 1-10 h to obtain the hollow rod-shaped Ni / In2O3 catalyst.

2. Use according to claim 1, characterized in that, The specific surface area S of the Ni / In2O3 catalyst BET is 20-50 m 2 / g, the pore volume V p is 0.1-1 cm 3 / g, the most probable pore diameter D BJH is 2-20 nm.

3. Use according to claim 1, characterized in that, The indium compound is indium chloride tetrahydrate or indium nitrate hydrate.

4. Use according to claim 1, characterized in that, In step (2), the drying temperature is 110 ℃, the drying time is 12 h, the calcination temperature is 450 ℃, and the calcination time is 4 h.

5. The use according to claim 1, characterized in that, In step (2), the content of Ni in the prepared catalyst is 1 wt%.

Images