Gallium-doped tin oxide-based catalyst as well as preparation method and application thereof
By using gallium-doped tin oxide-based catalysts under acidic conditions, the stability and selectivity of the CO2 electroreduction to formic acid were improved, solving the problem of insufficient stability and selectivity in the existing technology and realizing efficient CO2 reduction to formic acid.
Patent Information
- Application Number
- CN202510987374.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-17
- Publication Date
- 2025-10-31
AI Technical Summary
Existing catalysts for the electroreduction of CO2 to formic acid under acidic conditions have poor stability and low selectivity, making them difficult to apply industrially.
A gallium-doped tin oxide-based catalyst is used, with the active component being GaySnOx, where the nominal molar ratio of Ga to Sn is 0.
The stability and formic acid selectivity of the catalyst were improved under acidic conditions, achieving efficient CO2 reduction to formic acid with a Faraday efficiency of over 90% and stability of over 5000 hours.
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Figure CN120866867A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalytic catalyst technology, specifically to a gallium-doped tin oxide-based catalyst, its preparation method, and its application. Background Technology
[0002] Since the Industrial Revolution, the overuse of traditional fossil fuels has caused a severe energy crisis and environmental pollution. The combustion of fossil fuels releases excessive CO2, disrupting the natural carbon cycle, causing a severe greenhouse effect, and significantly impacting the Earth's climate. CO2 electroreduction technology, which utilizes renewable energy sources such as wind, tidal, and solar power to reduce the greenhouse gas CO2 and produce fuels, holds promise for helping to achieve global carbon neutrality and alleviate the energy crisis.
[0003] Among the many carbon dioxide reduction products, formic acid (HCOOH) has the highest added value per unit of electrical energy input. Therefore, the electroreduction of CO2 to HCOOH has good industrial application prospects. Main group metals, including Sn, Pb, In, and Bi, and their derivatives, have been widely reported for the synthesis of formate (HCOO) under neutral and alkaline conditions. - It has high activity (catalytic current density > 500 mA / cm²). -2 It exhibits high selectivity (Faraday efficiency > 90%). However, CO2 electroreduction technology under neutral / alkaline conditions has not yet been industrially applied because a large amount of CO2 dissolves during the reaction, leading to the common carbonate buildup on the gas diffusion layer, causing serious stability problems in neutral / alkaline systems and limiting its further development.
[0004] In contrast, proton-rich (H) + An acidic environment can eliminate carbonate precipitation, thus achieving high CO2 conversion efficiency and high stability. Simultaneously, under acidic conditions, the electroreduction of CO2 directly yields HCOOH instead of HCOO. - This reduces the acidification step in the purification process. However, in strongly acidic electrolytes, hydrogen evolution inhibition and catalyst stability issues are more severe. Developing durable acidic CO2 electroreduction electrocatalysts presents a significant challenge.
[0005] Tin oxide (SnO2) is a stable material under acidic conditions and exhibits good selectivity for the electroreduction of CO2 to formic acid. However, there is a lack of acidic CO2 electroreduction catalysts with both high stability and high selectivity in related technologies. Summary of the Invention
[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defects of poor catalyst stability and low selectivity in the electroreduction of acidic CO2 to formic acid in related technologies, thereby providing a gallium-doped tin oxide-based catalyst, its preparation method and application.
[0007] The technical solution adopted by the present invention is as follows:
[0008] The present invention provides a gallium-doped tin oxide-based catalyst, and the active component of the catalyst is Ga y SnO x ; where y is the nominal molar ratio of Ga and Sn, 0 < y ≤ 1; x represents oxygen vacancies, x ≤ 3.5.
[0009] It can be understood that when the ratio of Ga and Sn is 1:1 and the oxygen coordination of all metal elements is saturated, the maximum value of x is 3.5.
[0010] It can be understood that the nominal molar ratio is the molar ratio of Ga and Sn in the raw materials added in the preparation of the catalyst.
[0011] Preferably, the true molar ratio of Ga and Sn in the active component of the catalyst is 0.3-0.7:1.
[0012] Preferably, the gallium-doped tin oxide-based catalyst further includes a carrier; the active component coats the carrier;
[0013] Preferably, the average particle size of the carrier is 20-100 nm;
[0014] Preferably, the mass ratio of the active component of the catalyst to the carrier is 0.4-5:1.
[0015] Preferably, the carrier is selected from nano-carbon.
[0016] The present invention also provides a preparation method of a gallium-doped tin oxide-based catalyst. A mixed solution is obtained by mixing a tin salt, a gallium salt, a carrier, and a solvent. After the mixed solution undergoes reaction, filtration, and sintering, the gallium-doped tin oxide-based catalyst is obtained.
[0017] Preferably, the gallium salt is selected from but not limited to salts with trivalent gallium cations.
[0018] Preferably, the tin salt is selected from but not limited to salts with tetravalent tin cations.
[0019] Preferably, the molar ratio of gallium and tin in the mixed solution is y:1, where 0 < y ≤ 1.
[0020] Preferably, the concentration of the tin salt in the mixed solution is 3-24 g / L. Optionally, the concentration of the tin salt in the mixed solution is 3 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L or 24 g / L
[0021] Preferably, the molar ratio of the carrier to the tin salt is (1-2):1.
[0022] Preferably, the reaction temperature is 150-170℃ and the reaction time is 2-4 hours. Optionally, the reaction temperature is 150℃, 160℃, or 170℃ and the reaction time is 2 hours, 3 hours, or 4 hours.
[0023] Preferably, the sintering temperature is 300-650℃; the sintering time is 1-6h. Optionally, the sintering temperature is 300℃, 350℃, 450℃, 550℃, or 600℃; the sintering time is 1h, 2h, 3h, or 6h.
[0024] Preferably, the sintering process is carried out under a protective gas atmosphere;
[0025] Preferably, the protective gas is selected from at least one of argon and nitrogen.
[0026] Preferably, the tin salt is selected from, but not limited to, tin tetrachloride;
[0027] Preferably, the gallium salt is selected from, but not limited to, at least one of gallium nitrate and gallium chloride;
[0028] Preferably, the average particle size of the carrier is 20-100 nm;
[0029] Preferably, the carrier is selected from nano-carbon;
[0030] Preferably, the solvent includes water;
[0031] More preferably, the solvent includes ethylene glycol.
[0032] Preferably, the process of mixing tin salt, gallium salt, carrier, and solvent to obtain a mixed solution is as follows: dissolving tin salt in an organic solvent, then adding water to obtain a first solution; then adding gallium salt and carrier; and then stirring at 100-150°C for 50-70 minutes to obtain a mixed solution.
[0033] Preferably, the organic solution is selected from, but not limited to, ethylene glycol.
[0034] Preferably, after mixing the tin salt, gallium salt, support, and solvent to obtain a mixed solution, the process of adjusting the pH of the mixed solution is further included before the reaction begins; the pH is adjusted by adding an alkaline solution; preferably, the alkaline solution is selected from KOH solution; preferably, the pH of the adjusted mixed solution is 9-11.
[0035] The present invention also provides an application of the above-described catalyst or the gallium-doped tin oxide-based catalyst prepared by the above-described preparation method in the acidic electrocatalytic reduction of CO2 to formic acid.
[0036] The beneficial effects of this invention are:
[0037] The gallium-doped tin oxide-based catalyst provided by this invention will... 3+ Introducing tin oxide-based catalysts can construct a stable framework of oxygen-containing species, thereby enhancing the stability of Sn-O bonds within the structure, avoiding the irreversible self-reduction of tin oxide in reducing environments, and improving material stability; simultaneously, Ga... 3+ By regulating the electronic structure of tin oxide, the adsorption strength of CO2 and its reaction intermediates is optimized, and the catalytic activity is improved, thereby enhancing the selectivity of formic acid. Attached Figure Description
[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0039] Figure 1 Transmission electron microscope image of the nano-electrocatalyst prepared in Example 1;
[0040] Figure 2 X-ray powder diffraction pattern of the nano-electrocatalyst prepared in Example 1;
[0041] Figure 3 The electron paramagnetic resonance spectra of the catalysts prepared in the examples and comparative examples are shown below;
[0042] Figure 4 Thermogravimetric analysis results of the catalysts prepared in the examples and comparative examples are shown in the figure.
[0043] Figure 5 The Faradaic efficiency of the catalysts prepared in the examples and comparative examples for the electrocatalytic reduction of CO2 in an acidic flow electrolyzer at different currents is shown.
[0044] Figure 6 The it curve of CO2 reduction by the nano-electrocatalyst prepared in Example 1 at a certain potential in an acidic solid-state electrolytic cell and its Faraday efficiency with respect to formic acid are shown. Detailed Implementation
[0045] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.
[0046] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.
[0047] The average particle size of the carbon nanoparticles used in the examples and comparative examples is approximately 50 nm.
[0048] Example 1
[0049] This embodiment provides a Ga 0.85 SnO x The preparation of nano-electrocatalysts includes the following steps:
[0050] 5 mmol of SnCl4 was dissolved in 60 ml of ethylene glycol, and 10 ml of water and Ga(NO3)3 were added. The mixture was stirred and dissolved (the molar ratio of SnCl4 to Ga(NO3)3 was 1:0.85). Then, 0.1 g of nano-carbon powder was added. The mixture was heated and stirred until it was uniformly dispersed to obtain a dispersion (stirring temperature: 120℃; time: 60 min). The dispersion was added to a hydrothermal reactor and hydrothermally reacted at 160℃ for 3 h. After the reaction was completed, the product was centrifuged, washed, and dried. The product was then ground and annealed at 450℃ for 4 h under an argon atmosphere to obtain the final Ga. 0.85 SnO x Nano-electrocatalyst (where the measured molar ratio of Ga to Sn is 0.48:1).
[0051] Ga 0.85 SnO x Characterization of nano-electrocatalysts:
[0052] from Figure 1 It can be seen that the Ga prepared using this embodiment 0.85 SnO x Nano-electrocatalyst, approximately 5 nm in size (active component Ga) 0.85 SnO x (particle size); such as Figure 2 The Ga prepared as shown 0.85 SnO x The diffraction peaks of the nano-electrocatalyst and the SnO2 standard card are consistent, indicating that Ga doping did not change the basic structure of tin oxide.
[0053] Example 2
[0054] This embodiment provides a Ga 0.7 SnO x The preparation of nano-electrocatalysts includes the following steps:
[0055] 5 mmol of SnCl4 was dissolved in 60 ml of ethylene glycol, and 10 ml of water and Ga(NO3)3 were added. The mixture was stirred and dissolved (the molar ratio of SnCl4 to Ga(NO3)3 was 1:0.7). Then, 0.1 g of nano-carbon powder was added. The mixture was heated and stirred until it was uniformly dispersed to obtain a dispersion (stirring temperature: 120℃; time: 60 min). The dispersion was added to a hydrothermal reactor and hydrothermally reacted at 160℃ for 3 h. After the reaction was completed, the product was centrifuged, washed, and dried. The product was then ground and annealed at 450℃ for 4 h under an argon atmosphere to obtain the final Ga. 0.85 SnO x Nano-electrocatalyst (where the measured molar ratio of Ga to Sn is 0.36:1).
[0056] Example 3
[0057] This embodiment provides a GaSnO x The preparation of nano-electrocatalysts includes the following steps:
[0058] 5 mmol of SnCl4 was dissolved in 60 ml of ethylene glycol, and 10 ml of water and Ga(NO3)3 were added. The mixture was stirred and dissolved (the molar ratio of SnCl4 to Ga(NO3)3 was 1:1). Then, 0.1 g of nano-carbon powder was added. The mixture was heated and stirred until it was uniformly dispersed to obtain a dispersion (stirring temperature: 120 °C; time: 60 min). The above dispersion was added to a hydrothermal reactor and hydrothermally reacted at 160 °C for 3 h. After the reaction was completed, the product was centrifuged, washed, and dried. The product was then ground and annealed at 450 °C for 4 h under an argon atmosphere to obtain the final GaSnO. x Nano-electrocatalyst (where the measured molar ratio of Ga to Sn is 0.62:1).
[0059] Example 4
[0060] This embodiment provides a Ga 0.85 SnO x The preparation of nano-electrocatalysts includes the following steps:
[0061] 5 mmol of SnCl4 was dissolved in 60 ml of ethylene glycol, and 10 ml of water and Ga(NO3)3 were added. The mixture was stirred and dissolved (the molar ratio of SnCl4 to Ga(NO3)3 was 1:0.85). Then, 0.1 g of nano-carbon powder was added. The mixture was heated and stirred until it was uniformly dispersed to obtain a dispersion (stirring temperature: 120℃; time: 60 min). 1 M KOH was added to adjust the pH to 10. The above dispersion was added to a hydrothermal reactor and hydrothermally reacted at 160℃ for 3 h. After the reaction was completed, the product was centrifuged, washed, and dried. The product was then ground and annealed at 450℃ for 4 h under an argon atmosphere to obtain the final high-load Ga. 0.85SnO x Nano-electrocatalysts.
[0062] Example 5
[0063] This embodiment provides a Ga 0.85 SnO x The preparation of nano-electrocatalysts includes the following steps:
[0064] 5 mmol of SnCl4 was dissolved in 60 ml of ethylene glycol, and 10 ml of water and Ga(NO3)3 were added. The mixture was stirred and dissolved (the molar ratio of SnCl4 to Ga(NO3)3 was 1:0.85). Then, 0.1 g of nano-carbon powder was added. The mixture was heated and stirred until it was uniformly dispersed to obtain a dispersion (stirring temperature: 120℃; time: 60 min). The dispersion was added to a hydrothermal reactor and hydrothermally reacted at 160℃ for 3 h. After the reaction was completed, the product was centrifuged, washed, and dried. The product was then ground and annealed at 650℃ for 4 h under an argon atmosphere to obtain Ga(NO3)3 with high oxygen vacancy content. 0.85 SnO x Nano-electrocatalysts.
[0065] Comparative Example 1
[0066] This comparative example provides a method for preparing an electrocatalyst, comprising the following steps:
[0067] 2 mmol SnCl4 was dissolved in 60 ml of ethylene glycol, and 10 ml of water was added. The mixture was stirred until dissolved, and then 0.1 g of nano-carbon powder was added. The mixture was heated and stirred until it was uniformly dispersed to obtain a dispersion (stirring temperature: 120 °C; time: 60 min). The dispersion was added to a hydrothermal reactor and hydrothermally reacted at 160 °C for 3 h. After the reaction was completed, the product was centrifuged, washed, and dried. The product was then ground and annealed at 450 °C for 4 h under an argon atmosphere to obtain the final SnO. x Nano-electrocatalysts.
[0068] Comparative Example 2
[0069] This comparative example provides a method for preparing an electrocatalyst, comprising the following steps:
[0070] 5 mmol Ga(NO3)3 was dissolved in 60 ml of ethylene glycol, 10 ml of water was added, and the mixture was stirred and dissolved. Then, 0.1 g of nano-carbon powder was added. The mixture was heated and stirred until it was evenly dispersed to obtain a dispersion (stirring temperature: 120 °C; time: 60 min). The dispersion was added to a hydrothermal reactor and hydrothermally reacted at 160 °C for 3 h. After the reaction was completed, the product was centrifuged, washed and dried. The product was then ground and annealed at 450 °C for 4 h under an argon atmosphere to obtain the final Ga2O3 nano-electrocatalyst.
[0071] Test case
[0072] Electron paramagnetic resonance testing
[0073] Figure 3 Based on the electron paramagnetic resonance (EPR) test results, it can be found that Ga 0.85 SnO x Nano-electrocatalysts have a higher oxygen vacancy concentration.
[0074] Thermogravimetric test
[0075] Figure 4 The thermogravimetric analysis results show the catalyst loading on the support.
[0076] Catalytic performance test
[0077] Electrocatalytic performance test of gallium-doped tin oxide-based nano-electrocatalytic materials: Electrodes were prepared using catalysts obtained in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2, respectively.
[0078] In the flow cell tests, catalysts prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 were mixed with Nafion at a mass ratio of 6:1, and ethanol was added to prepare a slurry. The slurry was uniformly coated onto carbon paper and dried to serve as the cathode. A platinum sheet was used as the anode. The electrolyte consisted of sulfuric acid and 0.5M potassium sulfate at a pH of 1.7. Nafion 117 was used as the ion exchange membrane, and Ag / AgCl was used as the reference electrode. The test results are as follows: Figure 5 .
[0079] Solid-state electrolytic cell test at 10cm -2 The electrolysis was conducted in an electrolytic cell, using the catalyst from Example 1 as the cathode, an iridium oxide-coated Ti mesh as the anode, pure water as the flowing liquid in the ion exchange resin layer, and 0.5M sulfuric acid as the anolyte. Nafion 117 was used as the anolyte ion exchange membrane, a Sustainion anion exchange membrane as the cathode ion exchange membrane, and Amberlite IR-120 as the ion exchange resin. Performance test results are attached. Figure 6 .
[0080] The flow cell current density can be observed to be 500 mA / cm². -2 It still maintains ~90% of the formic acid faradaic efficiency, which is superior to most materials reported in the literature. At the same time, it exhibits excellent stability, ~100 mA cm⁻¹. -2 It can operate stably for more than 5000 hours.
[0081] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A gallium-doped tin oxide-based catalyst, characterized in that, The active component of the catalyst is Ga. y SnO x Where y is the nominal molar ratio of Ga to Sn, 0 <y≤1;x≤3.5。 2. The gallium-doped tin oxide-based catalyst according to claim 1, characterized in that, The gallium-doped tin oxide-based catalyst further includes a support; the active component coats the support. Preferably, the average particle size of the carrier is 20-100 nm; Preferably, the mass ratio of the active component of the catalyst to the support is 0.4 to 5:1; Preferably, the carrier is selected from nano-carbon.
3. A method for preparing a gallium-doped tin oxide-based catalyst, characterized in that, A mixed solution is obtained by mixing tin salt, gallium salt, support, and solvent. The mixed solution is then reacted, filtered, and sintered to obtain the gallium-doped tin oxide-based catalyst.
4. The preparation method according to claim 3, characterized in that, The molar ratio of gallium to tin in the mixed solution is y:1, where 0 <y≤1。 5. The preparation method according to claim 3 or 4, characterized in that, The concentration of tin salt in the mixed solution is 3-24 g / L.
6. The preparation method according to any one of claims 3-5, characterized in that, The molar ratio of the carrier to the tin salt is (1-2):
1.
7. The preparation method according to any one of claims 3-6, characterized in that, The reaction is carried out at a temperature of 150-170℃ for 2-4 hours.
8. The preparation method according to any one of claims 3-7, characterized in that, The sintering temperature is 300-650℃; the sintering time is 1-6h; Preferably, the sintering process is carried out under a protective gas atmosphere; Preferably, the protective gas is selected from at least one of argon and nitrogen.
9. The preparation method according to any one of claims 3-8, characterized in that, The tin salt is selected from tin tetrachloride; Preferably, the gallium salt is selected from at least one of gallium nitrate and gallium chloride; Preferably, the average particle size of the carrier is 20-100 nm; Preferably, the carrier is selected from nano-carbon; Preferably, the solvent includes water; More preferably, the solvent further includes ethylene glycol.
10. The application of the catalyst according to claim 1 or 2 or the gallium-doped tin oxide-based catalyst prepared by the preparation method according to any one of claims 3-9 in the acidic electrocatalytic reduction of CO2 to formic acid.