Iridium-antimony-tin ternary metal oxygen evolution catalyst and preparation method thereof

Abstract

The invention provides an iridium-antimony-tin ternary metal oxygen evolution catalyst and a preparation method thereof. The iridium-antimony-tin ternary metal oxygen evolution catalyst comprises a carrier and iridium oxide loaded on the carrier, and the carrier is antimony oxide doped with tin oxide. In the application, on one hand, oxides of rich metal elements antimony and tin in the earth crust are adopted as carriers, so that the use amount of scarce and expensive iridium is reduced, and the catalytic ability of the sites to the oxygen evolution reaction is further enhanced due to the introduction of iridium; on the other hand, through the synergistic effect of the three metals, more catalytic active sites are provided, the reaction energy barrier is reduced, and the intrinsic activity and reaction kinetics of the catalyst are improved; on the other hand, iridium, antimony and tin in the catalyst generate a synergistic effect, so that formation of a more stable crystal structure and a metal-oxygen bond is facilitated, and the structure of the catalyst is effectively prevented from being damaged. According to the iridium-antimony-tin ternary metal oxygen evolution catalyst, the activity, selectivity and stability of the oxygen evolution reaction are improved, and the overpotential is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of oxygen evolution catalysts, and in particular to an iridium-antimony-tin ternary metal oxygen evolution catalyst and a preparation method thereof. Background Art

[0002] Hydrogen production from water electrolysis is a key means of storing and converting renewable energy and holds significant significance. However, the oxygen evolution reaction at the anode during water electrolysis involves a complex four-electron transfer process. Conventional oxygen evolution catalysts exhibit slow reaction kinetics, low activity, and require high overpotentials, resulting in significant energy loss and low efficiency. This severely restricts the large-scale application of hydrogen production from water electrolysis.

[0003] At present, various types of materials have been developed in the field of oxygen evolution catalysts. Precious metal-based catalysts such as iridium dioxide (IrO2) or iridium black have excellent oxygen evolution activity and can work efficiently in the anode environment of electrolytic cells, but the scarcity and high cost of precious metals make them difficult to be widely used. Binary metal oxide catalysts, such as nickel iron oxide (NiFeO x ), cobalt manganese oxide (CoMnO x ), etc., with the synergistic effect of two metal elements, the performance is better than that of single metal oxides. However, due to the limitations of composition and structure, there is a bottleneck in the realization of its synergistic effect, and there is still room for improvement in terms of activity and stability. In addition, there are trimetallic organic framework material catalysts. For example, a trimetallic MOF oxygen evolution catalyst prepared by a one-step hydrothermal method using three metal salts of iron, manganese, and nickel and 1,2,4,5-benzenetetracarboxylic acid organic ligand has a three-dimensional flower-like nano-microsphere structure, a large specific surface area, and rich active sites. It shows high selectivity and good stability in the electrolysis of water for oxygen evolution reaction. However, MOF-derived materials have poor conductivity and need to be improved for practical application.

[0004] Existing iridium-based oxygen evolution reaction catalysts have many problems. On the one hand, the cost remains high. Iridium, as a rare precious metal, has a low annual production, resulting in high catalyst costs, which seriously hinders its large-scale application. On the other hand, the performance of iridium-based oxygen evolution reaction catalysts has room for further improvement. Although iridium-based oxygen evolution reaction catalysts are important materials for acidic oxygen evolution reaction, their oxygen evolution reaction catalytic performance is still far from that of ideal and efficient catalysts, making it difficult to meet industrial needs. At the same time, the stability of existing iridium-based catalysts still has room for improvement. When the oxygen evolution reaction occurs, the iridium nanoparticles in the catalyst are prone to Oswald ripening, the active sites are reduced, the particles are prone to agglomeration and shedding, the specific surface area is reduced, and the catalytic activity is low, which seriously restricts the oxygen evolution reaction in water electrolysis. Summary of the Invention

[0005] The main purpose of the present invention is to provide an iridium, antimony, and tin ternary metal oxygen evolution catalyst and its preparation method, so as to solve the problems of low catalytic activity, low overpotential, poor stability and high cost of oxygen evolution catalysts for hydrogen production by electrolysis of water in the prior art.

[0006] To achieve the above objectives, according to one aspect of the present invention, an iridium-antimony-tin ternary metal oxygen evolution catalyst is provided. The iridium-antimony-tin ternary metal oxygen evolution catalyst comprises a carrier and iridium oxide supported on the carrier, wherein the carrier is antimony oxide doped with tin oxide.

[0007] Furthermore, the molar ratio of the antimony oxide, tin oxide and iridium oxide is (0.02-0.9):(0.85-0.95):(0.5-2) based on the antimony atoms in antimony oxide, the tin atoms in tin oxide and the iridium atoms in iridium oxide.

[0008] Furthermore, the specific surface area of ​​the ternary metal oxygen evolution catalyst of iridium, antimony and tin is 30m 2 / g~55m 2 / g; and / or the average particle size of the ternary metal oxygen evolution catalyst of iridium, antimony and tin is 20nm to 500nm.

[0009] Furthermore, in the oxygen evolution reaction of water electrolysis in a three-electrode system, the Tafel slope of the above-mentioned iridium antimony tin ternary metal oxygen evolution catalyst was tested in a 0.5 mol / L H2SO4 solution environment and was 51-67 mV·dec. -1 and / or ternary metal oxygen evolution catalyst of iridium antimony tin in an acidic environment of pH = 0.3 to reach 10mA·cm -2 The overpotential η required for current density 10 258-281mV; and / or ternary metal oxygen evolution catalyst of iridium, antimony and tin at 1A·cm -2 When the stable operation time reaches 350h under the current density, the overpotential η 10 The decay rate is 10~30μV·h -1 .

[0010] According to another aspect of the present invention, a method for preparing the above-mentioned iridium, antimony, and tin ternary metal oxygen evolution catalyst is provided. The preparation method comprises: step S1, mixing raw materials including an antimony source, a tin source, a chelating agent, and a solvent, and then performing a sol-gel reaction to obtain a gel product; step S2, performing a first calcination on the gel product in an oxygen-containing atmosphere to obtain antimony oxide doped with tin oxide; step S3, mixing raw materials including antimony oxide doped with tin oxide, an iridium source, a chelating agent, and an oxidant, and performing a solvent evaporation treatment to obtain a primary product; and step S4, performing a second calcination on the primary product in an oxygen-containing atmosphere to obtain an iridium, antimony, and tin ternary metal oxide catalyst.

[0011] Further, in the above step S1, the molar ratio of the antimony source to the tin source is (0.02-0.9):(0.85-0.95); and / or the antimony source is selected from any one or more of antimony ethanol, antimony acetate, sodium antimonate, antimony iodide, antimony trichloride, antimony fluoride and antimony bromide; and / or the tin source is selected from any one or more of tin tetrachloride, stannous chloride, stannous sulfate and tin acetate; and / or the iridium source is an iridium-containing compound and / or a hydrate corresponding to the iridium-containing compound, and the iridium-containing compound is selected from any one or more of iridium trichloride, chloroiridic acid, potassium chloroiridate, sodium chloroiridate, ammonium chloroiridate, iridium acetate and iridium acetylacetonate; and / or the molar ratio of the chelating agent to the tin source is (0.18-2.14):1, and the chelating agent is selected from any one or more of ammonia water, hydrazine hydrate and triethylamine; and / or the solvent is selected from any one or more of isopropanol and n-propanol.

[0012] Furthermore, in the above step S2, the temperature of the first calcination is 300-700°C, preferably 400-550°C; and / or the time of the first calcination is 2-4 hours.

[0013] Furthermore, in the above step S3, the mass ratio of the oxidant to the iridium source is (5.5-10):1, and / or the oxidant is sodium nitrate and / or potassium nitrate.

[0014] Furthermore, in the above step S3, the molar ratio of the complexing agent to the iridium source is (45-100):1, and / or the complexing agent is selected from any one or more of hydrazine hydrate and ammonia water; and / or the molar ratio of antimony oxide doped with tin oxide to the iridium source is 1:(0.5-2).

[0015] Furthermore, in the above step S4, the temperature of the second calcination is 200-600° C., preferably 300-500° C., and / or the time of the second calcination is 2-4 hours.

[0016] The technical solution of the present application is applied. In the present application, on the one hand, the oxides of the metal elements antimony and tin, which are abundant in the earth's crust, are used as carriers to prepare oxygen evolution catalysts of ternary metal oxides, reduce the amount of scarce and expensive iridium, significantly cut the cost of oxygen evolution reaction materials, improve the utilization rate of resources, create conditions for its large-scale application, and the introduction of iridium further enhances the catalytic ability of these sites to oxygen evolution reaction. On the other hand, the synergistic effect between the three metals is utilized to provide more catalytic active sites, optimize the adsorption and desorption ability of the catalyst to the intermediate during the oxygen evolution reaction, reduce the reaction energy barrier, that is, reduce the overpotential of the oxygen evolution reaction, thereby improving the intrinsic activity and reaction kinetics of the catalyst. On the other hand, iridium, antimony and tin trimetallic in the catalyst produce synergistic effects, contribute to the formation of a more stable crystal structure and metal-oxygen bond, improve the corrosion resistance of the catalyst in corrosive media, effectively prevent the catalyst structure from being damaged, enhance the operational stability of the catalyst under harsh conditions, to meet industrial production needs. In summary, the ternary metal oxygen evolution catalyst of iridium, antimony and tin of the present application improves the activity, selectivity and stability of its oxygen evolution reaction and reduces the overpotential. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 Shows a scanning electron microscope (SEM) and element distribution mapping image of an iridium, antimony, and tin ternary metal oxygen evolution catalyst according to Example 3 of the present invention;

[0019] Figure 2 A polarization curve diagram of an iridium, antimony, and tin ternary metal oxygen evolution catalyst in an acidic environment according to Example 3 of the present invention is shown;

[0020] Figure 3 An overpotential diagram of an iridium, antimony, and tin ternary metal oxygen evolution catalyst according to Example 3 of the present invention is shown;

[0021] Figure 4 The Tafel plot of an iridium, antimony, and tin ternary metal oxygen evolution catalyst according to Example 3 of the present invention is shown. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] As described in the background technology section, the oxygen evolution catalysts for hydrogen production by electrolysis of water in the prior art have problems such as low catalytic activity, low overpotential, poor stability and high cost. In order to solve the above problems, the present invention provides an iridium, antimony and tin ternary metal oxygen evolution catalyst and a preparation method thereof.

[0024] In a typical embodiment of the present application, an iridium-antimony-tin ternary metal oxygen evolution catalyst is provided. The iridium-antimony-tin ternary metal oxygen evolution catalyst includes a carrier and iridium oxide supported on the carrier, wherein the carrier is antimony oxide doped with tin oxide.

[0025] In the present application, on the one hand, the oxides of the abundant metallic elements antimony and tin in the earth's crust are used as carriers to prepare the oxygen evolution catalyst of the ternary metal oxide, reduce the amount of scarce and expensive iridium, significantly cut the cost of oxygen evolution reaction materials, improve the utilization rate of resources, create conditions for its large-scale application, and the introduction of iridium further enhances the catalytic ability of these sites to oxygen evolution reaction;On the other hand, the synergistic effect between the three metals is utilized to provide more catalytic active sites, optimize the adsorption and desorption ability of the catalyst to the intermediate during the oxygen evolution reaction, reduce the reaction energy barrier, that is, reduce the overpotential of the oxygen evolution reaction, thereby improving the intrinsic activity and reaction kinetics of the catalyst;On the other hand, iridium, antimony and tin trimetallic in the catalyst produce synergistic effects, contribute to the formation of more stable crystal structure and metal-oxygen bond, improve the corrosion resistance of the catalyst in corrosive media, effectively prevent the catalyst structure from being damaged, enhance the operational stability of the catalyst under harsh conditions, to meet industrial production needs. In summary, the activity, selectivity and stability of its oxygen evolution reaction are improved by the iridium antimony tin ternary metal oxygen evolution catalyst of the present application, and the overpotential is reduced.

[0026] In some embodiments of the present application, the molar ratio of the antimony oxide, tin oxide and iridium oxide is (0.02-0.9):(0.85-0.95):(0.5-2), calculated as antimony atoms in antimony oxide, tin atoms in tin oxide, and iridium atoms in iridium oxide.

[0027] In the present application, by controlling the molar ratio of antimony oxide, tin oxide and iridium oxide within the above range, on the one hand, the electronic structure of the catalyst can be optimized, the synergistic effect between metals can be promoted, and it helps to provide more stable and abundant catalytic active sites; on the other hand, appropriate ratio control not only improves the stability of the catalyst, but also helps in the adsorption and desorption of oxygen evolution reaction intermediates, reduces the reaction energy barrier, and reduces the overpotential of the oxygen evolution reaction, thereby improving the efficiency and economy of the oxygen evolution reaction.

[0028] In some embodiments of the present application, the specific surface area of ​​the ternary metal oxygen evolution catalyst of iridium, antimony and tin is 30m 2 / g~55m 2 / g; and / or the average particle size of the ternary metal oxygen evolution catalyst of iridium, antimony and tin is 20nm to 500nm.

[0029] The specific surface area of ​​a catalyst is one of the important indicators of its catalytic performance. A higher specific surface area means that more catalytic active sites are exposed to the reaction medium, which is conducive to the full contact between the reactant molecules and the catalyst surface, thereby improving the rate and efficiency of the catalytic reaction. Therefore, the present application helps to increase the active sites of the iridium, antimony, tin ternary metal oxygen evolution catalyst by controlling the specific surface area of ​​the iridium, antimony, tin ternary metal oxygen evolution catalyst within the above range, so that it exhibits high activity in the oxygen evolution reaction. Among them, nano-sized catalyst particles have a higher surface energy on the one hand, which not only promotes the formation of metal active sites, but also accelerates the electron transfer process. Nano-size also helps to reduce the diffusion distance inside the catalyst, allowing reactants and products to be transferred between the catalyst surface and the interior faster, thereby improving the reaction kinetics. On the other hand, the size of the nanoparticles will affect the structural stability of the catalyst. Controlling the above iridium, antimony, tin ternary metal oxygen evolution catalyst particle size range can improve the structural stability of the catalyst particles, reduce the destruction of the catalyst structure during the oxygen evolution process, especially in high current density and corrosive environments, and maintain the stability and durability of the catalyst. In addition, nano-sized catalyst particles can form a more intimate contact and conductive network, which is particularly important for the electrolysis of water to produce hydrogen, because good conductivity can reduce energy loss and improve electrolysis efficiency. In summary, by precisely controlling the specific surface area and average particle size of the ternary metal oxygen evolution catalyst of iridium, antimony, and tin, its catalytic activity can be significantly improved, reaction kinetics can be optimized, structural stability can be enhanced, conductivity can be improved, and cost-effectiveness can be achieved.

[0030] In some embodiments of the present application, in the three-electrode system of water electrolysis oxygen evolution reaction, the Tafel slope of the above-mentioned iridium antimony tin ternary metal oxygen evolution catalyst was tested in a 0.5 mol / L H2SO4 solution environment and was 51-67 mV·dec. -1 and / or ternary metal oxygen evolution catalyst of iridium antimony tin in an acidic environment of pH = 0.3 to reach 10mA·cm -2 The overpotential η required for current density 10 258-281mV; and / or ternary metal oxygen evolution catalyst of iridium, antimony and tin at 1A·cm -2 When the stable operation time reaches 350h under the current density, the overpotential η 10 The decay rate is 10~30μV·h -1 .

[0031] The smaller the Tafel slope, the faster the kinetic process of the catalyst in the oxygen evolution reaction, the smaller the required voltage difference, that is, the higher the catalytic efficiency and the lower the energy consumption. In the environment of 0.5 mol / L H2SO4 solution, 51~67 mV·dec-1 The Tafel slope shows that this ternary metal oxygen evolution catalyst has excellent kinetic performance, which is conducive to the rapid progress of oxygen evolution reaction and helps to improve energy utilization. -2 The overpotential η required for current density 10 is 258-281mV, indicating that the ternary metal oxygen evolution catalyst can start the oxygen evolution reaction at a lower overpotential, proving that the ternary metal oxygen evolution catalyst of iridium antimony tin is beneficial to improving the start-up efficiency of the reaction. Operating at a lower voltage can reduce electrochemical corrosion to the electrolytic cell, which is beneficial to reducing overall operating and maintenance costs. The low decay rate indicates that the ternary metal oxygen evolution catalyst of iridium antimony tin can maintain stable performance during high-intensity electrolysis, which can reduce the frequency of catalyst replacement, thereby reducing operating costs and improving the economic efficiency of production. It can be seen that the catalyst with the above Tafel slope and overpotential η 10 As well as the overpotential decay rate in long-term operation, it helps the catalyst to have excellent performance such as high catalytic activity, low energy consumption, and long life in an acidic environment.

[0032] In another typical embodiment of the present application, a method for preparing an iridium-antimony-tin ternary metal oxygen evolution catalyst is provided. The preparation method comprises: step S1, mixing raw materials including an antimony source, a tin source, a chelating agent, and a solvent, and then conducting a sol-gel reaction to obtain a gel product; step S2, calcining the gel product in an oxygen-containing atmosphere to obtain antimony oxide doped with tin oxide; step S3, mixing raw materials including antimony oxide doped with tin oxide, an iridium source, a chelating agent, and an oxidant, and evaporating the solvent to obtain a primary product; step S4, calcining the primary product in an oxygen-containing atmosphere to obtain an iridium-antimony-tin ternary metal oxide catalyst.

[0033] Step S1 enables the antimony source, tin source, and chelating agent to be uniformly dispersed in the solvent to form a highly dispersed gel, which is conducive to laying a structural foundation for the formation of a uniform antimony oxide-doped tin oxide carrier, and then helps the metal atoms to be evenly distributed in the gel network. Step S2 is carried out in an oxygen-containing atmosphere to further promote the crystallization and stabilization of the metal oxide, thereby forming a structurally stable antimony oxide-doped tin oxide carrier. Step S3 mixes the carrier with an iridium source, a complexing agent, and an oxidant and carries out solvent evaporation. This process helps the iridium atoms to be uniformly and deeply loaded into the pores and surface of the carrier, thereby increasing the number of active sites and further optimizing the electron conduction path, thereby improving the overall activity and stability of the iridium antimony tin ternary metal oxygen evolution catalyst. The calcination of step S4 is conducive to strengthening the bonding between the metal and the oxide carrier, and can promote the formation of a ternary metal oxide structure. In summary, the above preparation method uses the oxides of the metal elements antimony and tin as carriers to prepare a medium-iridium antimony-tin ternary metal oxygen evolution catalyst, which can not only improve its catalytic activity, stability, corrosion resistance and industrial production feasibility, but also significantly reduce the amount of scarce and expensive iridium, thereby greatly reducing the cost of the oxygen evolution catalyst.

[0034] In addition, the above-mentioned preparation of antimony-tin bimetallic oxide can adopt a hydrothermal synthesis method, wherein an antimony source, a tin source and a solvent are placed in a reactor equipped with a polytetrafluoroethylene lining, and after a hydrothermal reaction treatment at a certain temperature, an antimony oxide-doped tin oxide carrier is obtained by high-temperature heat treatment in an air atmosphere; the antimony oxide-doped tin oxide carrier is mixed with an iridium source, a surfactant and a solvent to prepare an iridium-antimony-tin ternary metal oxygen evolution catalyst by a liquid phase reflux method.

[0035] In one embodiment of the present application, in the preparation method of the above-mentioned iridium, antimony, and tin ternary metal oxygen evolution catalyst, in step S1, the molar ratio of the antimony source to the tin source is (0.02-0.9):(0.85-0.95); and / or the antimony source is selected from any one or more of antimony ethanol, antimony acetate, sodium antimonate, antimony iodide, antimony trichloride, antimony fluoride and antimony bromide; and / or the tin source is selected from any one or more of tin tetrachloride, stannous chloride, stannous sulfate and tin acetate; and / or the iridium source is an iridium-containing compound and / or a hydrate corresponding to the iridium-containing compound, and the iridium-containing compound is selected from any one or more of iridium trichloride, chloroiridic acid, potassium chloroiridate, sodium chloroiridate, ammonium chloroiridate, iridium acetate and iridium acetylacetonate; and / or the molar ratio of the chelating agent to the tin source is (0.18-2.14):1, and the chelating agent is selected from any one or more of ammonia water, hydrazine hydrate and triethylamine; and / or the solvent is selected from any one or more of isopropanol and n-propanol.

[0036] In step S1, the mol ratio of limiting antimony source and tin source can optimize the electronic structure of ternary metal oxide, contribute to the effective formation of antioxidation and oxygen evolution active site. Different types of antimony source and tin source (such as antimony ethanol, tin tetrachloride etc.) can promote the uniform distribution of metal ions in sol-gel reaction process, this reduces the risk of agglomeration caused by the excessively high local concentration, can make the catalyst of preparation have high dispersity and large specific surface area, thus increase the density of catalytic active site. Select suitable iridium source and its and the ratio of complexing agent (such as hydrazine hydrate), can affect the dispersity of iridium and the bonding strength of iridium and carrier, be conducive to iridium oxide composition and stably load on antimony tin oxide carrier in preparation process. The mol ratio of chelating agent and tin source and the selection of solvent can affect the efficiency of sol-gel reaction and the structure of product. Suitable chelating agent mol ratio can better complex metal ion again, thus form stable sol, and the selection of above solvent species then contributes to control reaction rate, forms the gel structure with high porosity and large specific surface area, and contributes to the formation of catalyst active site and increases electronic conduction ability. The combined effect of controlling the above conditions is beneficial to improving the comprehensive performance of the catalyst, including improving catalytic activity, stability and corrosion resistance, while also taking into account lower preparation costs.

[0037] In one embodiment of the present application, in step S2, the temperature of the first calcination is 300-700° C., preferably 400-550° C.; and / or the time of the first calcination is 2-4 hours.

[0038] Excessively low first calcination temperatures and times are detrimental to the crystallization of the metal oxides, while excessively high calcination temperatures and times may lead to premature sintering of the catalyst, reducing its high specific surface area and active sites. Controlling the first calcination temperature within the above ranges helps strengthen the chemical bonding between the metal oxides, thereby forming an ordered and stable lattice structure and enhancing the robustness of the metal-oxygen bond. It also helps form nanoscale particles, increasing the specific surface area of ​​the catalyst, thereby providing more active sites and improving the chemical stability and mechanical strength of the catalyst.

[0039] In one embodiment of the present application, in step S3, the mass ratio of the oxidant to the iridium source is (5.5-10):1, and / or the oxidant is sodium nitrate and / or potassium nitrate.

[0040] On the one hand, an excessive amount of iridium source may lead to unnecessary cost increases, and an insufficient amount of iridium source may reduce the activity of the catalyst. Controlling the mass ratio of the oxidant and the iridium source helps to promote the full oxidation of the iridium element during the preparation process, thereby forming a uniformly distributed iridium oxide, and optimizing the distribution of iridium atoms in the catalyst structure to form more active sites. On the other hand, the mass ratio of the above oxidant and the iridium source can promote the combination of iridium atoms and antimony / tin oxide carriers, which is conducive to the formation of a highly uniform and strong ternary metal oxide structure; based on zinc oxide and excellent stability at high temperatures, sodium nitrate and / or potassium nitrate are selected as oxidants. The oxidizing environment they provide in the reaction is conducive to improving the selectivity of the reaction, which helps to form the desired iridium oxide structure and reduce the probability of side reactions. At the same time, the oxidant is low in cost and easy to obtain. The reaction of the oxidant with the iridium compound can achieve controllable reaction conditions, which makes it possible to simplify the preparation process and effectively reduce the cost of catalyst production, thereby promoting its application and popularization on an industrial scale.

[0041] In one embodiment of the present application, in step S3, the molar ratio of the complexing agent to the iridium source is (45-100):1, and / or the complexing agent is selected from any one or more of hydrazine hydrate and ammonia water; and / or the molar ratio of antimony oxide doped with tin oxide to the iridium source is 1:(0.5-2).

[0042] The above-specified molar ratios of the complexing agent to the iridium source, as well as the molar ratio of the tin oxide-doped antimony oxide to the iridium source, promote uniform dispersion of the iridium element on the tin oxide-doped antimony oxide support and provide suitable porosity, particle size, and specific surface area, thereby effectively enhancing the catalyst's reactivity, stability, and corrosion resistance. Complexing agents such as hydrazine hydrate can form stable complexes with iridium before high-temperature treatment, promoting uniform distribution on the support and effectively reducing the risk of agglomeration caused by excessively high local iridium concentrations, thereby forming more active sites and enhancing catalytic performance.

[0043] In one embodiment of the present application, in step S4, the temperature of the second calcination is 200-600° C., preferably 300-500° C., and / or the time of the second calcination is 2-4 hours.

[0044] During the second calcination process, the valence state and electron distribution of the metal atoms can be adjusted, promoting the homogenization and stabilization of the ternary metal oxide, and forming more active sites, effectively reducing the reaction energy barrier, thereby reducing the overpotential, and further achieving the balance and optimization of the catalyst performance. The optimized second calcination temperature and time within the above range help form a stable chemical bond between the metal oxides, promote the strengthening of the metal-oxide bond, and form a more ordered and stable crystal structure. Reduce the risk of catalyst structure damage caused by excessively high temperatures, promote the complete formation of the ternary metal oxygen evolution catalyst of iridium, antimony, and tin, and improve the structural stability and catalytic efficiency of the catalyst.

[0045] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0046] Example 1

[0047] (1) 2.2811 g of antimony trichloride, 17.0658 g of tin tetrachloride, and 10 mL of ammonia water were dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor;

[0048] (2) The gel precursor in step (1) was placed in a muffle furnace and heat treated at 500°C in an air atmosphere at a heating rate of 5°C min -1 , heat treatment time 2h, cooling to room temperature, to obtain antimony oxide doped tin oxide;

[0049] (3) Weigh 1 g of the antimony oxide-doped tin oxide obtained in step (2), 1.759 g of chloroiridic acid, 10 mL of hydrazine hydrate, and 10 g of sodium nitrate, dissolve them in 20 mL of isopropanol, stir and dissolve them at room temperature, and evaporate the solvent isopropanol to dryness to obtain a primary product;

[0050] (4) The primary product obtained in step (3) was refrigerated at 5°C min under air atmosphere. -1 The ternary metal oxygen evolution catalyst of iridium, antimony and tin was obtained by high temperature pyrolysis at 350℃ for 3h and finally cooled to room temperature.

[0051] (5) The Ir content of the catalyst was 40 wt % using ICP-MS. The catalyst was then prepared into catalyst ink and its overpotential was measured in a 0.5 M H 2 SO 4 solution in a three-electrode system. The Tafel slope was calculated, and the result was η 10 =263mV, Tafel slope 54mV·dec -1 .

[0052] Example 2

[0053] (1) 4.5622 g of antimony trichloride, 15.1696 g of tin tetrachloride, and 10 mL of ammonia water were dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor;

[0054] (2) The gel precursor in step (1) was placed in a muffle furnace and heat treated at 500°C in an air atmosphere at a heating rate of 5°C min -1 , heat treatment time 2h, cooling to room temperature, to obtain antimony oxide doped tin oxide;

[0055] (3) Weigh 1 g of the antimony oxide-doped tin oxide obtained in step (2), 1.759 g of chloroiridic acid, 10 mL of hydrazine hydrate, and 10 g of sodium nitrate, dissolve them in 20 mL of isopropanol, stir and dissolve them at room temperature, and evaporate the solvent isopropanol to dryness to obtain a primary product;

[0056] (4) The primary product obtained in step (3) was refrigerated at 5°C min under air atmosphere. -1 The ternary metal oxygen evolution catalyst of iridium, antimony and tin was obtained by high temperature pyrolysis at 350℃ for 3h and finally cooled to room temperature.

[0057] (5) The Ir content of the catalyst was 40 wt % using ICP-MS. The catalyst was then prepared into catalyst ink and its overpotential was measured in a 0.5 M H 2 SO 4 solution in a three-electrode system. The Tafel slope was calculated, and the result was η 10 =258mV, Tafel slope 51mV·dec -1 .

[0058] Example 3

[0059] (1) 6.8433 g of antimony trichloride, 13.2734 g of tin tetrachloride, and 10 mL of ammonia water were dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor;

[0060] (2) The gel precursor in step (1) was placed in a muffle furnace and heat treated at 500°C in an air atmosphere at a heating rate of 5°C min -1 , heat treatment time 2h, cooling to room temperature, to obtain antimony oxide doped tin oxide;

[0061] (3) Weigh 1 g of the antimony oxide-doped tin oxide obtained in step (2), 1.759 g of chloroiridic acid, 10 mL of hydrazine hydrate, and 10 g of sodium nitrate, dissolve them in 20 mL of isopropanol, stir and dissolve them at room temperature, and evaporate the solvent isopropanol to dryness to obtain a primary product;

[0062] (4) The primary product obtained in step (3) was refrigerated at 5°C min under air atmosphere. -1 The ternary metal oxygen evolution catalyst of iridium, antimony and tin was obtained by pyrolysis at 350℃ for 3h and finally cooled to room temperature. The SEM and element distribution mapping pictures are shown in Fig. Figure 1 shown.

[0063] (5) The Ir content of the catalyst was 40 wt % using ICP-MS. The catalyst was then prepared into catalyst ink and its overpotential was measured in a 0.5 M H 2 SO 4 solution in a three-electrode system. The Tafel slope was calculated, and the result was η 10 =266mV, Tafel slope 55mV·dec -1 .

[0064] Example 4

[0065] (1) 11.4055 g of antimony trichloride, 9.481 g of tin tetrachloride, and 10 mL of ammonia water were dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor;

[0066] (2) The gel precursor in step (1) was placed in a muffle furnace and heat treated at 500°C in an air atmosphere at a heating rate of 5°C min -1 , heat treatment time 2h, cooling to room temperature, to obtain antimony oxide doped tin oxide;

[0067] (3) Weigh 1 g of the antimony oxide-doped tin oxide obtained in step (2), 1.759 g of chloroiridic acid, 10 mL of hydrazine hydrate, and 10 g of sodium nitrate, dissolve them in 20 mL of isopropanol, stir and dissolve them at room temperature, and evaporate the solvent isopropanol to dryness to obtain a primary product;

[0068] (4) The primary product obtained in step (3) was refrigerated at 5°C min under air atmosphere. -1 The ternary metal oxygen evolution catalyst of iridium, antimony and tin was obtained by high temperature pyrolysis at 350℃ for 3h and finally cooled to room temperature.

[0069] (5) The Ir content of the catalyst was 40 wt % using ICP-MS. The catalyst was then prepared into catalyst ink and its overpotential was measured in a 0.5 M H 2 SO 4 solution in a three-electrode system. The Tafel slope was calculated, and the result was η 10 =272mV, Tafel slope 59mV·dec -1 .

[0070] Example 5

[0071] (1) 13.6866 g of antimony trichloride, 7.5848 g of tin tetrachloride, and 10 mL of ammonia water were dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor;

[0072] (2) The gel precursor in step (1) was placed in a muffle furnace and heat treated at 500°C in an air atmosphere at a heating rate of 5°C min -1 , heat treatment time 2h, cooling to room temperature, to obtain antimony oxide doped tin oxide;

[0073] (3) Weigh 1 g of the antimony oxide-doped tin oxide obtained in step (2), 1.759 g of chloroiridic acid, 10 mL of hydrazine hydrate, and 10 g of sodium nitrate, dissolve them in 20 mL of isopropanol, stir and dissolve them at room temperature, and evaporate the solvent isopropanol to dryness to obtain a primary product;

[0074] (4) The primary product obtained in step (3) was refrigerated at 5°C min under air atmosphere. -1 The ternary metal oxygen evolution catalyst of iridium, antimony and tin was obtained by high temperature pyrolysis at 350℃ for 3h and finally cooled to room temperature.

[0075] (5) The Ir content of the catalyst was 40 wt % using ICP-MS. The catalyst was then prepared into catalyst ink and its overpotential was measured in a 0.5 M H 2 SO 4 solution in a three-electrode system. The Tafel slope was calculated, and the result was η 10 =281mV, Tafel slope 67mV·dec -1 .

[0076] Example 6

[0077] The difference from Example 1 is that 2.9891 g of antimony acetate, 17.0658 g of tin tetrachloride, and 10 mL of ammonia water are dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor, and finally an iridium antimony tin ternary metal oxygen evolution catalyst is obtained.

[0078] Example 7

[0079] The difference from Example 1 is that 2.2811 g of antimony trichloride, 14.07 g of stannous sulfate, and 10 mL of ammonia water are dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor, and finally an iridium antimony tin ternary metal oxygen evolution catalyst is obtained.

[0080] Example 8

[0081] The difference from Example 1 is that 2.2811 g of antimony trichloride, 17.0658 g of tin tetrachloride, and 5 mL of hydrazine hydrate are dissolved in 100 mL of 50% ethanol aqueous solution, heated at 60° C. for 3 h to form a sol, and then cooled to room temperature to obtain a gel precursor, and finally an iridium antimony tin ternary metal oxygen evolution catalyst is obtained.

[0082] Example 9

[0083] The difference from Example 1 is that the gel precursor in step (1) is placed in a muffle furnace and heat-treated at 400° C. in an air atmosphere to obtain antimony oxide doped with tin oxide, and finally obtain an iridium antimony tin ternary metal oxygen evolution catalyst.

[0084] Example 10

[0085] The difference from Example 1 is that the gel precursor in step (1) is placed in a muffle furnace and heat-treated at 300° C. in an air atmosphere to obtain antimony oxide doped with tin oxide, and finally obtain an iridium antimony tin ternary metal oxygen evolution catalyst.

[0086] Example 11

[0087] The difference from Example 1 is that the gel precursor in step (1) is placed in a muffle furnace and heat-treated at 700° C. in an air atmosphere to obtain antimony oxide doped with tin oxide, and finally obtain an iridium antimony tin ternary metal oxygen evolution catalyst.

[0088] Example 12

[0089] The difference from Example 1 is that the primary product obtained in step (3) is pyrolyzed at 500° C. for 3 h in an air atmosphere to finally obtain an iridium-antimony-tin ternary metal oxygen evolution catalyst.

[0090] Example 13

[0091] The difference from Example 1 is that the primary product obtained in step (3) is pyrolyzed at 200° C. for 3 h in an air atmosphere to finally obtain an iridium-antimony-tin ternary metal oxygen evolution catalyst.

[0092] Example 14

[0093] The difference from Example 1 is that the molar ratio of antimony trichloride to tin tetrachloride is 0.1:0.88, and an iridium antimony tin ternary metal oxygen evolution catalyst is finally obtained.

[0094] Example 15

[0095] The difference from Example 1 is that the molar ratio of antimony trichloride to tin tetrachloride is 0.1:0.6, and an iridium antimony tin ternary metal oxygen evolution catalyst is finally obtained.

[0096] Example 16

[0097] The difference from Example 1 is that the molar ratio of ammonia water to tin tetrachloride is 2.14:1, and the ternary metal oxygen evolution catalyst of iridium, antimony and tin is finally obtained.

[0098] Example 17

[0099] The difference from Example 1 is that the molar ratio of ammonia water to tin tetrachloride is 0.1:1, and the ternary metal oxygen evolution catalyst of iridium, antimony and tin is finally obtained.

[0100] Example 18

[0101] The difference from Example 1 is that the mass ratio of sodium nitrate to chloroiridic acid is 9:1, and the ternary metal oxygen evolution catalyst of iridium, antimony and tin is finally obtained.

[0102] Example 19

[0103] The difference from Example 1 is that the mass ratio of sodium nitrate to chloroiridic acid is 12:1, and the ternary metal oxygen evolution catalyst of iridium, antimony and tin is finally obtained.

[0104] Example 20

[0105] The difference from Example 1 is that the molar ratio of the complexing agent hydrazine hydrate to chloroiridic acid is 88:1, and the ternary metal oxygen evolution catalyst of iridium, antimony and tin is finally obtained.

[0106] Example 21

[0107] The difference from Example 1 is that the molar ratio of the complexing agent hydrazine hydrate to chloroiridic acid is 36:1, and the ternary metal oxygen evolution catalyst of iridium, antimony and tin is finally obtained.

[0108] Comparative Example 1:

[0109] The difference from Example 1 is that the catalyst is IrO2.

[0110] Comparative Example 2:

[0111] The difference from Example 1 is that antimony oxide is used instead of tin oxide to dope antimony oxide, and finally an iridium-antimony-tin ternary metal oxygen evolution catalyst is obtained.

[0112] Performance testing:

[0113] The mass ratio of iridium, antimony, and tin ions in the ternary metal oxygen evolution catalyst (Ir / Antimony-Sn) was determined by weighing 0.1-0.5 g of catalyst sample into a polytetrafluoroethylene (PTFE) digestion tube. 10 mL of aqua regia was added and digested in a graphite digester at a temperature programmed to 160°C. A standard solution of the sample was prepared and the calibration curve for the inductively coupled plasma-mass spectrometer (ICP-MS) was calibrated using the standard addition method. Finally, the sample was analyzed by ICP-MS for elemental metal content. Three replicates were performed for each sample, and the average value was calculated.

[0114] Specific surface area of ​​ternary metal oxygen evolution catalysts (iridium, antimony, and tin): Take 100-200 mg of catalyst sample (adjust according to the specific surface area to ensure the adsorption amount is ≥0.1 mL / g), place it in a sample tube, and record the sample mass m (accurate to 0.1 mg). Connect the sample tube to the surface area analyzer degassing station for heating and degassing. Use high-purity nitrogen as the adsorbent and helium as the carrier gas to calibrate the surface area analyzer. Then measure the adsorption-desorption curve of the catalyst sample. Finally, calculate the specific surface area of ​​the catalyst sample based on the adsorption-desorption curve and the BJH model. This scheme also complies with the international standard ISO9277:2010 and is suitable for quantitative characterization of catalyst specific surface area. The reliability of the results can be ensured by repeated testing (parallel samples ≤3 times, relative deviation ≤5%).

[0115] Average particle size of the iridium, antimony, and tin ternary metal oxygen evolution catalyst: 5-10 mg of catalyst powder (concentration 0.1-1.0 mg / mL) was placed in a 50 mL centrifuge tube. 20 mL of ethanol was then added as the dispersion medium, and ultrasonic dispersion was performed at room temperature for at least 60 minutes. Finally, the particle size distribution of the catalyst sample was measured using a laser particle size analyzer.

[0116] The molar ratio, specific surface area and average particle size of antimony oxide, tin oxide and iridium oxide in the ternary metal oxygen evolution catalysts of the above examples and comparative examples were tested, and the test data are listed in Table 1.

[0117] Table 1

[0118]

[0119]

[0120] The catalysts obtained in the above examples and comparative examples were prepared into catalyst ink for testing. In the electrolysis of water and oxygen evolution reaction in a three-electrode system, the Tafel slope of the iridium antimony tin ternary metal oxygen evolution catalyst was obtained by testing in a 0.5 mol / L H2SO4 solution environment. The iridium antimony tin ternary metal oxygen evolution catalyst reached 10 mA·cm in an acidic environment of pH = 0.3. -2 The overpotential η required for current density 10 ; Iridium, antimony, tin ternary metal oxygen evolution catalyst at 1A·cm -2 When the stable operation time reaches 350h under the current density, the overpotential η 10 The test results are listed in Table 2.

[0121] Table 2

[0122]

[0123]

[0124] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0125] In the present application, on the one hand, the oxides of the abundant metallic elements antimony and tin in the earth's crust are used as carriers to prepare the oxygen evolution catalyst of the ternary metal oxide, reduce the amount of scarce and expensive iridium, significantly cut the cost of oxygen evolution reaction materials, improve the utilization rate of resources, create conditions for its large-scale application, and the introduction of iridium further enhances the catalytic ability of these sites to oxygen evolution reaction;On the other hand, the synergistic effect between the three metals is utilized to provide more catalytic active sites, optimize the adsorption and desorption ability of the catalyst to the intermediate during the oxygen evolution reaction, reduce the reaction energy barrier, that is, reduce the overpotential of the oxygen evolution reaction, thereby improving the intrinsic activity and reaction kinetics of the catalyst;On the other hand, iridium, antimony and tin trimetallic in the catalyst produce synergistic effects, contribute to the formation of more stable crystal structure and metal-oxygen bond, improve the corrosion resistance of the catalyst in corrosive media, effectively prevent the catalyst structure from being damaged, enhance the operational stability of the catalyst under harsh conditions, to meet industrial production needs. In summary, the activity, selectivity and stability of its oxygen evolution reaction are improved by the iridium antimony tin ternary metal oxygen evolution catalyst of the present application, and the overpotential is reduced.

[0126] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An iridium, antimony, and tin ternary metal oxygen evolution catalyst, characterized in that: The iridium-antimony-tin ternary metal oxygen evolution catalyst comprises a carrier and iridium oxide supported on the carrier, wherein the carrier is antimony oxide doped with tin oxide.

2. The ternary metal oxygen evolution catalyst of iridium, antimony and tin according to claim 1, characterized in that: Calculated based on the antimony atoms in the antimony oxide, the tin atoms in the tin oxide, and the iridium atoms in the iridium oxide, the molar ratio of the antimony oxide, the tin oxide, and the iridium oxide is (0.02-0.9):(0.85-0.95):(0.5-2).

3. The iridium, antimony, and tin ternary metal oxygen evolution catalyst according to claim 1 or 2, characterized in that: The specific surface area of ​​the ternary metal oxygen evolution catalyst of iridium, antimony and tin is 30m 2 / g~55m 2 / g; and / or the average particle size of the iridium, antimony and tin ternary metal oxygen evolution catalyst is 20nm to 500nm.

4. The iridium, antimony, and tin ternary metal oxygen evolution catalyst according to any one of claims 1 to 3, characterized in that In the oxygen evolution reaction of water electrolysis in a three-electrode system, the Tafel slope of the iridium, antimony, and tin ternary metal oxygen evolution catalyst tested in a 0.5 mol / L H2SO4 solution environment was 51-67 mV·dec. -1 and / or the iridium antimony tin ternary metal oxygen evolution catalyst reaches 10mA·cm in an acidic environment of pH = 0.3 -2 The overpotential η required for current density 10 is 258-281mV; and / or the iridium antimony tin ternary metal oxygen evolution catalyst is 1A·cm -2 When the stable operation time reaches 350h under the current density, the overpotential η 10 The decay rate is 10~30μV·h -1 .

5. A method for preparing the ternary metal oxygen evolution catalyst of iridium, antimony and tin according to any one of claims 1 to 4, characterized in that: The preparation method comprises: Step S1, mixing raw materials including an antimony source, a tin source, a chelating agent and a solvent and performing a sol-gel reaction to obtain a gel product; Step S2, calcining the gel product in an oxygen-containing atmosphere to obtain antimony oxide doped with tin oxide; Step S3, mixing the raw materials including the antimony oxide doped with tin oxide, an iridium source, a complexing agent, and an oxidant, and performing a solvent evaporation treatment to obtain a primary product; Step S4: performing a second calcination on the primary product in an oxygen-containing atmosphere to obtain the iridium-antimony-tin ternary metal oxide catalyst.

6. The preparation method according to claim 5, characterized in that In the step S1, the molar ratio of the antimony source to the tin source is (0.02-0.9):(0.85-0.95); and / or, the antimony source is selected from any one or more of antimony ethanol, antimony acetate, sodium antimonate, antimony iodide, antimony trichloride, antimony fluoride and antimony bromide; And / or, the tin source is selected from any one or more of tin tetrachloride, stannous chloride, stannous sulfate and tin acetate; And / or, the iridium source is an iridium-containing compound and / or a hydrate corresponding to the iridium-containing compound, and the iridium-containing compound is selected from any one or more of iridium trichloride, chloroiridic acid, potassium chloroiridate, sodium chloroiridate, ammonium chloroiridate, iridium acetate and iridium acetylacetonate; and / or, the molar ratio of the chelating agent to the tin source is (0.18-2.14):1, and the chelating agent is selected from any one or more of ammonia water, hydrazine hydrate and triethylamine; And / or, the solvent is selected from any one or more of isopropyl alcohol and n-propyl alcohol.

7. The preparation method according to claim 5 or 6, characterized in that: In the step S2, the temperature of the first calcination is 300-700°C, preferably 400-550°C; and / or the time of the first calcination is 2-4 hours.

8. The preparation method according to any one of claims 5 to 7, characterized in that In step S3, the mass ratio of the oxidant to the iridium source is (5.5-10):1, and / or the oxidant is sodium nitrate and / or potassium nitrate.

9. The preparation method according to any one of claims 5 to 8, characterized in that In step S3, the molar ratio of the complexing agent to the iridium source is (45-100):1, and / or the complexing agent is selected from any one or more of hydrazine hydrate and ammonia water; and / or the molar ratio of the antimony oxide doped with tin oxide to the iridium source is 1:(0.5-2).

10. The preparation method according to any one of claims 5 to 9, characterized in that In the step S4, the temperature of the second calcination is 200-600° C., preferably 300-500° C., and / or the time of the second calcination is 2-4 hours.

Images