In2O3 loaded Ni monatomic photocatalyst as well as preparation method and application thereof
By preparing Ni single-atom photocatalyst supported on In2O3, the problems of low utilization of active sites and metal agglomeration in the CO2 reduction process of existing photocatalysts were solved, realizing a highly efficient CO2 reduction to CO reaction, improving the reaction rate and selectivity, and extending the service life of the catalyst.
Patent Information
- Application Number
- CN202511536692.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-27
- Publication Date
- 2026-01-27
AI Technical Summary
Existing photocatalysts suffer from problems such as low utilization of active sites, poor reaction selectivity, and reduced reaction rate due to metal agglomeration during the CO2 to CO reduction process.
A Ni single-atom photocatalyst supported on In2O3 was prepared by the sol-gel method. Ni was highly dispersed in single-atom form on the surface or lattice defects of In2O3. The metal loading and preparation process were optimized to form a catalyst with high reactivity, high selectivity and stable structure.
It significantly improves the reaction rate and selectivity of CO2 reduction to CO, extends the catalyst's lifespan, and efficiently utilizes solar energy under near-infrared light.
Smart Images
Figure CN121402091A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalyst technology, specifically to an In2O3-supported Ni single-atom photocatalyst, its preparation method, and its applications. Background Technology
[0002] Photocatalytic CO2 reduction (CO2RR) technology, which uses solar energy to reduce CO2 into high-value chemicals, has great potential, especially in the production of carbon monoxide (CO).
[0003] CO is not only an important basic chemical raw material, but also a fuel carrier. However, while existing technologies such as thermocatalysis, electrocatalysis, and biocatalysis can produce CO, they have disadvantages such as high energy consumption, low selectivity, and slow reaction rates. Photocatalysis, on the other hand, is particularly advantageous in terms of energy efficiency, operating conditions, product selectivity, and environmental friendliness by utilizing solar energy, a green resource, to efficiently convert CO2 into CO under normal temperature and pressure conditions.
[0004] Most existing catalysts suffer from low active site utilization and poor reaction selectivity, making it crucial to improve catalyst activity and stability in CO2 reduction reactions. In recent years, single-atom catalysts, as nanomaterials with higher active site utilization, have significantly improved reaction rates and selectivity. However, existing single-atom catalysts often exhibit metal aggregation during the reaction, leading to the transformation of single atoms into nanoparticles, which drastically reduces the reaction rate.
[0005] To overcome these shortcomings, this invention provides an ultra-stable metal oxide-supported Ni single-atom photocatalyst for CO2 reduction to CO and its preparation method. Summary of the Invention
[0006] The purpose of this invention is to provide an In2O3-supported Ni single-atom photocatalyst, its preparation method, and its applications. By optimizing the catalyst metal loading and preparation process, it exhibits excellent performance in terms of high reactivity, high product selectivity, high structural stability, and mild reaction conditions, thereby effectively improving the CO2 reduction reaction rate and extending the catalyst's lifespan.
[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing an In2O3-supported Ni single-atom photocatalyst includes the following steps: S1. Add nickel acetate tetrahydrate to an aqueous solution of indium nitrate and stir until homogeneous to obtain a mixed metal solution; S2. Add ammonium carbonate to the metal mixture solution to cause hydrolysis and obtain a sol system. S3. Filter the sol system to obtain a wet gel-like solid phase substance; S4. The wet gel-like solid material is dried, ground, and calcined to obtain an In2O3-supported Ni single-atom catalyst. S5. Next, the Ni single-atom catalyst supported on In2O3 is ground again to obtain the In2O3@Ni-SG photocatalyst.
[0008] As a further aspect of the present invention, the mass ratio of indium nitrate to nickel acetate tetrahydrate is 2.113:0.106.
[0009] As a further embodiment of the present invention, the mass ratio of indium nitrate, nickel acetate tetrahydrate and ammonium carbonate is 2.113:0.106:1.445.
[0010] As a further aspect of the present invention: Preparation of indium nitrate aqueous solution: 2.113g of indium nitrate was dispersed in 200mL of deionized water and ultrasonically dispersed for 5 minutes.
[0011] As a further aspect of the present invention: the hydrolysis reaction time is 5 hours and the temperature is 70°C.
[0012] As a further aspect of the present invention: the drying temperature is 60°C and the drying time is 24 hours.
[0013] As a further aspect of the present invention, the calcination process is as follows: calcination is carried out in air at a heating rate of 5°C per minute to 600°C for 5 hours.
[0014] An In₂O₃-supported Ni single-atom photocatalyst, the photocatalyst comprising: In2O3-supported Ni single-atom photocatalysts are prepared using indium oxide (In2O3) as a support via a sol-gel method, with Ni highly dispersed in single-atom form on the surface of In2O3 or at its lattice defects.
[0015] As a further aspect of the present invention, the Ni content in the photocatalyst accounts for 1-10 wt% of the total catalyst.
[0016] Application of an In2O3-supported Ni single-atom photocatalyst, which is used for photocatalytic CO2 reduction to CO under sunlight or infrared light.
[0017] The beneficial effects of this invention are: The catalyst of this invention employs the following technical solution: Ni metal single atoms are loaded onto an In₂O₃ support. In₂O₃, as a photoresponsive support, possesses a unique band gap structure and abundant surface oxygen vacancies, which helps enhance the adsorption and activation of CO₂ molecules. Atomically dispersed Ni accumulates near oxygen vacancies, forming active sites with locally high electron density, effectively promoting the breaking of C=O bonds. At the Ni single atom-In₂O₃ interface, electron-photogenerated hole recombination is delayed, extending the lifetime of photogenerated carriers and improving charge transfer efficiency. In summary, In₂O₃-loaded Ni single atoms significantly enhance the CO₂ reduction to CO production effect. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 The X-ray diffraction (XRD) patterns of In2O3, In2O3@Ni-SG, and Ni / In2O3-BH obtained in Example 4 are shown.
[0020] Figure 2 The image shows the UV-Vis absorption spectrum of In2O3@Ni-SG obtained in Example 4.
[0021] Figure 3 The image shows the surface thermometry infrared imaging of the reaction process of In2O3, In2O3@1Ni-SG, In2O3@2Ni-SG, In2O3@2.5Ni-SG, In2O3@3Ni-SG, In2O3@5Ni-SG, In2O3@10Ni-SG, and 2.5Ni / In2O3-BH obtained in Example 4.
[0022] Figure 4 Transmission electron microscopy (TEM) and particle size distribution diagrams of In2O3@Ni-SG and Ni / In2O3-BH obtained in Example 4.
[0023] Figure 5 This is an aberration-corrected transmission electron microscope (AC-TEM) image of In2O3@Ni-SG obtained in Example 4.
[0024] Figure 6The reaction activity diagrams for In2O3, In2O3@1Ni-SG, In2O3@2Ni-SG, In2O3@2.5Ni-SG, In2O3@3Ni-SG, In2O3@5Ni-SG, In2O3@10Ni-SG, and 2.5Ni / In2O3-BH obtained in Example 4 are shown. Detailed Implementation
[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0026] Example 1 An In2O3-supported Ni single-atom photocatalyst provided in this embodiment of the invention comprises: In2O3-supported Ni single-atom photocatalyst is prepared by sol-gel method using indium oxide (In2O3) as support. Ni is highly dispersed in single-atom form on the surface of In2O3 or at its lattice defects, and has good photoresponse ability and photocatalytic activity. The Ni content in the photocatalyst accounts for 1 wt% of the total catalyst.
[0027] Example 2 An In2O3-supported Ni single-atom photocatalyst provided in this embodiment of the invention comprises: In2O3-supported Ni single-atom photocatalyst is prepared by sol-gel method using indium oxide (In2O3) as support. Ni is highly dispersed in single-atom form on the surface of In2O3 or at its lattice defects, and has good photoresponse ability and photocatalytic activity. The Ni content in the photocatalyst accounts for 2.5 wt% of the total catalyst.
[0028] Example 3 An In2O3-supported Ni single-atom photocatalyst provided in this embodiment of the invention comprises: In2O3-supported Ni single-atom photocatalyst is prepared by sol-gel method using indium oxide (In2O3) as support. Ni is highly dispersed in single-atom form on the surface of In2O3 or at its lattice defects, and has good photoresponse ability and photocatalytic activity. The Ni content in the photocatalyst accounts for 10 wt% of the total catalyst.
[0029] Example 4 This invention provides a method for preparing an In2O3-supported Ni single-atom photocatalyst, comprising the following steps: S1. Add nickel acetate tetrahydrate to an aqueous solution of indium nitrate and stir until homogeneous to obtain a mixed metal solution; The mass ratio of indium nitrate to nickel acetate tetrahydrate is 2.113:0.106. In S1, the specific preparation process of the metal mixed solution includes the following steps: In a single-necked flask, 2.113 g of indium nitrate was dispersed in 200 mL of deionized water and ultrasonically dispersed for 5 minutes. Then, 0.106 g of nickel acetate tetrahydrate was added and magnetically stirred for 5 minutes at room temperature to obtain a homogeneous metal mixture solution. S2. Add ammonium carbonate to the metal mixture solution to cause hydrolysis and obtain a sol system. The mass ratio of indium nitrate, nickel acetate tetrahydrate, and ammonium carbonate is 2.113:0.106:1.445. This substance is used to adjust the pH of the system and promote the hydrolysis of the mixed solution of indium nitrate and nickel acetate tetrahydrate to generate hydroxide precursors. In S2, the specific preparation process of the sol system includes the following steps: Add 1.445g of ammonium carbonate to the solution and stir continuously for 30 minutes. Then stir at 700rpm for 5 hours in a 70℃ water bath. During this process, the metal salt undergoes hydrolysis to form a stable sol system. S3. Filter the sol system to obtain a wet gel-like solid phase substance; In S3, the preparation process of the wet gel-like solid phase material is as follows: After cooling the sol to room temperature, it was filtered using a membrane filter with a pore size of 0.2 micrometers to remove the aqueous solution and obtain a wet gel-like solid phase. Unreacted ions and impurities in the gel system are removed by using a thin film to ensure purity; S4. The wet gel-like solid material is dried, ground, and calcined to obtain an In2O3-supported Ni single-atom catalyst. In S4, the preparation process of the In2O3-supported Ni single-atom catalyst is as follows: The obtained wet gel was dried in an oven at 60°C for 24 hours, ground into powder, and then placed in a tube furnace. It was calcined in air at a heating rate of 5°C per minute to 600°C for 5 hours to form an In2O3-supported Ni single-atom catalyst. S5. Next, the Ni single-atom catalyst supported on In2O3 is ground again to obtain the In2O3@Ni-SG photocatalyst. In S5, the preparation process of the In2O3@Ni-SG photocatalyst is as follows: After cooling and re-grinding, the In2O3@Ni-SG photocatalyst was finally obtained.
[0030] Example 5 The application of an In2O3-supported Ni single-atom photocatalyst provided in this invention includes the following steps: Photocatalysts are used for the photocatalytic reduction of CO2 to CO under sunlight or infrared light.
[0031] Performance testing Catalyst structure and performance evaluation: 20 mg of the photocatalyst described above was placed in a U-shaped quartz in-situ reaction cell. The photocatalytic performance was evaluated using a 300W xenon lamp with a wavelength (λ) controlled within the range of 200-2500 nm, and the light intensity was controlled at 1.5 W·cm². -2 First, the entire reaction system was evacuated using a high-power vacuum pump for 20 minutes. Then, a mixed gas (main components: 90% argon, 10% hydrogen) at 60 kPa was introduced. The temperature was raised to 300°C at a rate of 10°C / min and held for 30 minutes for in-situ reduction. After reduction and cooling to room temperature, a 60 kPa mixer (50% argon, 45% hydrogen, 5% carbon dioxide) was introduced to continue the reaction, achieving an In₂O₃@Ni-SG concentration of 999.01 μmol g. -1 h -1 The CO production was measured, and the carbon monoxide product selectivity reached 99.57%. The concentrations of CO and CH4 were detected by gas chromatography using an FID detector and a TCD detector.
[0032] Figure 1 The images show the X-ray diffraction (XRD) patterns of In2O3, In2O3@Ni-SG, and Ni / In2O3-BH obtained in Example 4. After the introduction of Ni, no intrinsic structural changes were observed except for the absence of the 211 crystal plane in In2O3@Ni-SG. This is because the introduction of Ni single atoms during calcination causes the In2O3 unit cell to shrink, resulting in a smaller particle size and weaker diffraction peaks. This indicates that the introduction of Ni single atoms can enhance the structural shrinkage of In2O3@Ni-SG during the preparation process. No diffraction peaks were observed for Ni nanoparticles, indicating that their content is low or they are highly dispersed on the In2O3 surface.
[0033] Figure 2 The images show the absorption spectra and performance of In2O3, In2O3@Ni-SG, and Ni / In2O3-BH obtained in Example 4 at different wavelengths.
[0034] Photocatalytic activities were compared using different light wavelengths (200-400 nm, 400-800 nm, 800-1000 nm). The results showed that the highest catalytic performance was observed in the near-infrared (IR) band (800-1000 nm), followed by the visible band, while the lowest catalytic activity was observed in the UV band. This trend suggests that near-infrared light may primarily promote catalytic reactions through photoinduced heat, and also confirms that In2O3@Ni-SG can serve as an infrared photocatalyst for efficient utilization of solar energy.
[0035] Figure 3 The images show infrared (IR) images of the surface temperatures of the In2O3, In2O3@1Ni-SG, In2O3@2Ni-SG, In2O3@2.5Ni-SG, In2O3@3Ni-SG, In2O3@5Ni-SG, In2O3@10Ni-SG, and 2.5Ni / In2O3-BH catalysts obtained in Example 4. The actual surface reaction temperatures of all catalysts were measured using an infrared camera. After 5 minutes of reaction, the surface temperature of In2O3 was 147°C, while that of In2O3@Ni-SG and Ni / In2O3-BH was 169°C, indicating that the presence of Ni improved the photothermal properties of In2O3.
[0036] Figure 4 The images show transmission electron microscopy (TEM) images and particle size distribution diagrams of In2O3@Ni-SG and Ni / In2O3-BH obtained in Example 4. (The images are shown in the original text.) Figure 4 a and Figure 4 b indicates that different Ni loading forms did not change the microstructure of In2O3, but showed that Ni single-atom loading reduced the catalyst particle size.
[0037] Figure 5 The image shows an aberration-corrected transmission electron microscope (AC-TEM) image of In2O3@Ni-SG obtained in Example 4. The image shows the signal intensity distribution in a specific region (corresponding to the white line region). The presence of isolated, low-intensity Ni is evident, and EDS confirms the atomic-level dispersion of Ni. O is also uniformly distributed without any sintering or agglomeration. Ni is enriched around and on oxygen vacancies (Vo) (indicated by the marked circles). This distribution pattern suggests that Ni single atoms may form a stable anchoring state with In2O3 through chemisorption or coordination environment of oxygen vacancies.
[0038] Figure 6Table 1 shows the reactivity diagrams of In2O3, In2O3@1Ni-SG, In2O3@2Ni-SG, In2O3@2.5Ni-SG, In2O3@3Ni-SG, In2O3@5Ni-SG, In2O3@10Ni-SG, and 2.5Ni / In2O3-BH obtained in Example 4.
[0039] Table 1 For In₂O₃, the CO reaction rate is 79.65 μmol g. -1 h -1 The reaction rate of CH4 is 14.35 μmol g. -1 h -1 The selectivity was relatively low at 84.73%; when the Ni loading reached 1%, the CO reaction rate was 363.87 μmol g. -1 h -1 The CH4 reaction rate is 18.7 μmol g. -1 h -1 The yields of both CO and CH4 increased, with a selectivity reaching 95.11%; this indicates that the introduction of Ni can promote the reaction efficiency of the reverse water-gas shift reaction and greatly improve the CO selectivity. Increasing the loading to 2% resulted in a CO reaction rate of 685.32 μmol g / L. -1 h -1 The CH4 reaction rate is 2.18 μmol g. -1 h -1 The selectivity reached 99.68%; at a loading of 3%, the CO reaction rate was 452.84 μmol g / L. -1 h -1 ; Further increasing the loading to 5% and 10%, the CO reaction rates were 464.78 μmol / g, respectively. -1 h -1 and 303.49 μmol g -1 h -1 Therefore, it was hypothesized that there might be a Ni loading level between 2% and 3% that would achieve the highest CO production rate. Thus, In₂O₃@2.5Ni-SG was prepared, achieving a CO reaction rate of 999.01 μmol g⁻¹. -1 h -1 The CH4 reaction rate is only 4.25 μmol g. -1 h -1The CO selectivity reached 99.57%; its CO yield was 12.5 times that of In₂O₃, indicating that the optimal Ni content is approximately 2.5 wt%. To investigate the influence of different preparation methods on the Ni loading form and material properties, a Ni / In₂O₃-BH photocatalyst with a Ni loading of 2.5 wt% and supported in nanoparticle form was prepared via sodium borohydride reduction as a comparison, exhibiting a CO reaction rate of 573.48 μmol g⁻¹. -1 h -1 The selectivity was 98.78%. The comparative results showed that Ni single atoms significantly enhanced the photocatalytic activity of CO2 hydrogenation, while the supported nanoparticles reduced the catalytic performance.
[0040] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.
Claims
1. A method for preparing an In₂O₃-supported Ni single-atom photocatalyst, characterized in that, Includes the following steps: S1. Add nickel acetate tetrahydrate to an aqueous solution of indium nitrate and stir until homogeneous to obtain a mixed metal solution; S2. Add ammonium carbonate to the metal mixture solution to cause hydrolysis and obtain a sol system. S3. Filter the sol system to obtain a wet gel-like solid phase substance; S4. The wet gel-like solid material is dried, ground, and calcined to obtain an In2O3-supported Ni single-atom catalyst. S5. Next, the Ni single-atom catalyst supported on In2O3 is ground again to obtain the In2O3@Ni-SG photocatalyst.
2. The method for preparing an In₂O₃-supported Ni single-atom photocatalyst according to claim 1, characterized in that, The mass ratio of indium nitrate to nickel acetate tetrahydrate is 2.113:0.
106.
3. The method for preparing an In₂O₃-supported Ni single-atom photocatalyst according to claim 1, characterized in that, The mass ratio of indium nitrate, nickel acetate tetrahydrate, and ammonium carbonate is 2.113:0.106:1.
445.
4. The method for preparing an In₂O₃-supported Ni single-atom photocatalyst according to claim 1, characterized in that, Preparation of indium nitrate aqueous solution: 2.113g of indium nitrate was dispersed in 200mL of deionized water and ultrasonically dispersed for 5 minutes.
5. The method for preparing an In₂O₃-supported Ni single-atom photocatalyst according to claim 1, characterized in that, The hydrolysis reaction took 5 hours and was carried out at a temperature of 70°C.
6. The method for preparing an In₂O₃-supported Ni single-atom photocatalyst according to claim 1, characterized in that, The drying temperature is 60℃ and the time is 24 hours.
7. The method for preparing an In₂O₃-supported Ni single-atom photocatalyst according to claim 1, characterized in that, The calcination process is as follows: calcination is carried out in air at a heating rate of 5°C per minute to 600°C for 5 hours.
8. An In₂O₃-supported Ni single-atom photocatalyst, characterized in that, The photocatalyst is prepared by the method according to any one of claims 1-7, and the photocatalyst comprises: In2O3-supported Ni single-atom photocatalyst is prepared by using indium oxide (In2O3) as a support and employing the sol-gel method. Ni is highly dispersed in single-atom form on the surface of In2O3 or at its lattice defects.
9. The method for preparing an In₂O₃-supported Ni single-atom photocatalyst according to claim 1, characterized in that, The Ni content in the photocatalyst accounts for 1-10 wt% of the total catalyst.
10. The use of an In₂O₃-supported Ni single-atom photocatalyst, characterized in that, The photocatalyst is prepared by the method described in any one of claims 1-7, and the photocatalyst is applied to the photocatalytic reduction of CO2 to CO under sunlight or infrared light.