Preparation and Application of a Supported Ir Group Cluster Catalyst with High Electrocatalytic Performance

Abstract

The present invention belongs to the fields of materials, chemistry and catalytic technology, and discloses the preparation and application of a supported Ir group cluster catalyst with high electrocatalytic performance. The supported Ir group cluster catalyst with high electrocatalytic performance of the present invention is prepared by the following steps: (1) immersing a carrier in an Ir precursor solution; (2) taking out the carrier and then performing heat treatment on the carrier to obtain the supported Ir group cluster catalyst. The process of the present invention is simple and easy to operate, can prepare a variety of highly active supported Ir group cluster catalysts, and the obtained catalysts have electrocatalytic performance of low cost, high activity and high stability, and have significant advantages in the fields of energy storage and the like.

Description

Technical Field

[0001] The present invention belongs to the technical fields of materials, chemistry, and catalysis, and particularly relates to the preparation and application of a supported Ir group cluster catalyst with high electrocatalytic performance. Background Art

[0002] To achieve the goals of efficient and low-cost electrocatalysis, a crucial issue is to improve the utilization efficiency of metal atoms in noble metal-based materials. Reducing the size of nanocrystals to sub-nanometer metal clusters or even single atoms is considered an effective strategy. Compared with nanocrystals, the low coordination and unsaturated configurations of sub-nanometer metal clusters and single-atom catalysts not only increase the number of catalytic active sites but also have unique atomic structures and electronic properties, making them exhibit higher activity and selectivity than nanocrystal catalysts in a large number of catalytic reactions. More importantly, reducing the size of noble metal-based nanocrystal catalysts to sub-nanometer sizes or even embedding them into supports with carefully designed atomic and electronic structures can serve as an ideal model for studying complex catalytic reactions and designing economically and environmentally friendly sustainable hydrogen production catalysts. However, it is still very difficult to rationally design sub-nanometer cluster catalysts with high activity and high stability.

[0003] Therefore, the preparation methods and performance studies of supported Ir-based group cluster catalysts need to be further investigated. Summary of the Invention

[0004] To overcome the above-mentioned drawbacks and deficiencies of the prior art, the primary object of the present invention is to provide a preparation method for a supported Ir group cluster catalyst with high electrocatalytic performance.

[0005] Another object of the present invention is to provide a supported Ir group cluster catalyst with high electrocatalytic performance prepared by the above method.

[0006] Another object of the present invention is to provide the application of the above-mentioned supported Ir group cluster catalyst with high electrocatalytic performance in the field of energy storage.

[0007] The objects of the present invention are achieved by the following solutions:

[0008] A preparation method for a supported Ir group cluster catalyst with high electrocatalytic performance, comprising the following steps:

[0009] (1) Immerse the support in an Ir precursor solution;

[0010] (2) Take out the support and then heat-treat the support to obtain a supported Ir group cluster catalyst.

[0011] The carrier described in step (1) is a defective carrier or a carrier capable of electrostatic adsorption with Ir species, including but not limited to at least one of carbon materials, oxides, sulfides, phosphides, and metal hydroxides.

[0012] Preferably, the carbon material is at least one of graphene, carbon nanotubes, carbon nitride, mesoporous carbon, carbon black, and glassy carbon; the oxide is at least one of titanium dioxide, cerium dioxide, cobalt oxide, cobalt tetroxide, yttrium oxide, niobium pentoxide, molybdenum trioxide, molybdenum dioxide, nickel oxide, copper oxide, cuprous oxide, indium oxide, manganese oxide, and manganese tetroxide; the sulfide is at least one of nickel sulfide, zinc sulfide, molybdenum sulfide, iron sulfide, manganese sulfide, and cadmium sulfide; the phosphide is at least one of molybdenum phosphide, nickel phosphide, nickel molybdenum phosphide, iron phosphide, manganese phosphide, and titanium phosphide; the metal hydroxide is at least one of cobalt hydroxide, nickel hydroxide, iron hydroxide, copper hydroxide, yttrium hydroxide, and molybdenum hydroxide.

[0013] The Ir precursor described in step (1) includes but not limited to at least one of iridium chloride, iridic acid, iridium acetate, ammonium hexachloroiridate, potassium hexachloroiridate, and sodium hexachloroiridate.

[0014] The solvent of the Ir precursor solution described in step (1) includes but not limited to at least one of water, ethanol, ethylene glycol, acetone, chloroform, and dimethylformamide.

[0015] The concentration of the Ir precursor solution described in step (1) is 0.00001 - 10.0 mol / L; preferably 0.001 - 0.01 mol / L.

[0016] The dosages of the carrier and the precursor solution in step (1) satisfy that the carrier can be completely immersed in the precursor solution.

[0017] The immersion time described in step (1) is 10 min - 48 h, preferably 30 min - 10 h; the impregnation occurs at room temperature.

[0018] The removal of the carrier described in step (2) is preferably carried out by suction filtration and centrifugation.

[0019] Before the heat treatment described in step (2), it is preferred to dry the carrier first, preferably at room temperature - 100 °C.

[0020] The heating temperature of the heat treatment described in step (2) is 150 - 600 °C; the heating time is 30 min - 30 h; the heating atmosphere can be one or a mixture of at least two of nitrogen, argon, ammonia, helium, and air.

[0021] Preferably, the heating temperature of the heat treatment in step (2) is 300 °C; the heating atmosphere is an inert atmosphere, such as at least one of nitrogen, argon, and helium; under these conditions, the iridium precursor decomposes and then Ir clusters are synthesized.

[0022] Preferably, after the heat treatment in step (2), the support is washed and dried; the washing solution is at least one of water and ethanol; the drying temperature is room temperature - 80 °C

[0023] A supported Ir group cluster catalyst prepared by the above method.

[0024] For the supported Ir group cluster catalyst described above, the size of the Ir group clusters is 0.1 - 10 nanometers, preferably 0.1 - 1.2 nanometers.

[0025] The application of the above supported Ir group cluster catalyst in the field of energy storage, especially in electrocatalytic oxygen evolution.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] The present invention provides a method for preparing a supported Ir group cluster catalyst with high catalytic performance. The process is simple and easy to operate, and can prepare a variety of supported Ir group cluster catalysts with high activity. Combining the characteristics of the support and the unique properties of the Ir group clusters, the present invention can not only accurately prepare various Ir group cluster catalysts, but also has electrocatalytic performance with low cost, high activity and high stability, and has significant advantages in the field of energy storage and other fields. Description of the Drawings

[0028] Figure 1 It is a transmission electron microscope image of the Ir group clusters prepared in Example 1 of the present invention.

[0029] Figure 2 It is the electrocatalytic performance of the Ir group clusters prepared by the method of the present invention. Among them, the first catalyst refers to the catalyst synthesized in Example 1, the second catalyst refers to the catalyst synthesized in Example 2, and the third catalyst refers to the catalyst synthesized in Example 5.

[0030] Figure 3 It is an X-ray photoelectron spectroscopy diagram of the Ir group clusters prepared in Example 1 of the present invention. Detailed Embodiments

[0031] The present invention will be further described in detail below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto. Those not specified in the examples are carried out under conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0032] The reagents used in the examples can be routinely purchased from the market without special instructions.

[0033] The preparation steps of the carrier (Ni-Mo-P grown on carbon paper) in Example 1 are as follows: First, 5 mmol / L nickel chloride and 1 mmol / L ammonium molybdate are completely dissolved in 60 mL of deionized water, and then 22.5 mmol / L urea is added to the mixed solution. After continuous stirring for 1 h, a uniform green solution is obtained. Then, the above uniform green solution and carbon paper are placed in a 100 mL Teflon-lined stainless steel hydrothermal autoclave and annealed at 120 °C in an incubator for 6 h. After the hydrothermal method is completed, the obtained Ni-Mo precursor (Ni-Mo / CP) is repeatedly washed with water and ethanol in turn, dried overnight in a furnace at 60 °C, and the obtained sample is Ni-Mo / CP (0.5 g). The above-synthesized Ni-Mo / CP and 1 g of sodium hypophosphite powder are respectively placed in two crucibles. In order to obtain effective phosphating treatment, the crucible with sodium hypophosphite is placed on the upstream side, and the distance between the two crucibles is 5 cm. Then, a phosphorylation reaction is carried out under a N2 flow at 550 °C for 1 hour, and Ni-Mo-P grown on carbon paper is successfully synthesized.

[0034] The mesoporous carbon in Example 2 was purchased from Xianfeng Nano in Nanjing, with the number XFP12.

[0035] Ni(OH)2 in Example 3 was purchased from Macklin.

[0036] The CdS nanocrystals in Example 4 were prepared by the following method: At room temperature, 10 mL of 0.05 mol / L CrCl3 was added dropwise to 10 mL of 0.05 mol / L Na2S at a rate of 10 mL / h.

[0037] CeO2 in Example 5 was purchased from Macklin, spherical with a size of 20 nm - 50 nm, 99.5%.

[0038] Example 1: Preparation of ultrafine Ir cluster / Ni-Mo-P.

[0039] First, Ni-Mo-P grown on carbon paper was selected as the carrier and immersed in 5 mL of 0.005 mol / L iridium chloride aqueous solution at room temperature for 30 minutes. Here, the dosage of the carrier and the precursor solution was such that the carrier could be completely immersed in the precursor solution; then the carrier was taken out with tweezers and dried naturally. The dried carrier was placed in a tubular furnace and heated in flowing nitrogen at 300 °C for 1 hour. After heating, it was repeatedly washed with deionized water and ethanol and then dried at 60 °C to obtain the Ir cluster catalyst.

[0040] Example 2: Preparation of Ir cluster / mesoporous carbon catalyst.

[0041] First, select mesoporous carbon as the carrier and immerse it in 5 mL of an aqueous solution of iridium chloride acid with a concentration of 0.001 mol / L at room temperature for 10 hours. Here, the amounts of the carrier and the precursor solution are such that the carrier can be completely immersed in the precursor solution. Then, filter out the solid by suction, place it in a tubular furnace, and heat it in argon at 400 °C for 10 hours. After heating, wash it repeatedly with deionized water and ethanol and then dry it at room temperature to obtain the Ir cluster / mesoporous carbon catalyst.

[0042] Example 3: Preparation of Ir cluster / Ni(OH)2 nanocatalyst.

[0043] First, select the Ni(OH)2 nanocatalyst as the carrier and immerse it in 5 mL of an aqueous solution of iridium chloride acid with a concentration of 0.010 mol / L at room temperature for 1 hour. Here, the amounts of the carrier and the precursor solution are such that the carrier can be completely immersed in the precursor solution. Then, centrifuge to remove the solid, place it in a tubular furnace, and heat it in air at 200 °C for 2 hours. After heating, wash it repeatedly with deionized water and ethanol and then dry it at 80 °C to obtain the Ir cluster / Ni(OH)2 nanocatalyst.

[0044] Example 4: Preparation of Ir cluster / CdS nanocatalyst.

[0045] First, select CdS nanocrystals as the carrier and immerse them in 5 mL of an aqueous solution of iridium chloride acid with a concentration of 0.005 mol / L at room temperature for 1 hour. Here, the amounts of the carrier and the precursor solution are such that the carrier can be completely immersed in the precursor solution. Then, centrifuge to remove the solid, place it in a tubular furnace, and heat it in nitrogen at 300 °C for 2 hours. After heating, wash it repeatedly with deionized water and ethanol and then dry it at 80 °C to obtain the Ir cluster / CdS nanocatalyst.

[0046] Example 5: Preparation of Ir cluster / CeO2 nanocatalyst.

[0047] First, select CeO2 nanocrystals as the carrier and immerse them in 5 mL of an aqueous solution of iridium chloride acid with a concentration of 0.001 mol / L at room temperature for 1 hour. Here, the amounts of the carrier and the precursor solution are such that the carrier can be completely immersed in the precursor solution. Then, centrifuge to remove the solid, place it in a tubular furnace, and heat it in ammonia at 400 °C for 2 hours. After heating, wash it repeatedly with deionized water and ethanol and then dry it at 50 °C to obtain the Ir cluster / CeO2 nanocatalyst.

[0048] Figure 1It is the morphology diagram of the sample of Ir-NMP synthesized in Example 1, indicating that the Ir species therein exist in the form of cluster structures on the surface of Ni-Mo-P. The bright spots shown in the figure are Ir clusters, and their sizes are between 0.1 and 1.2 nanometers.

[0049] Figure 2 It is the performance diagram of the electrocatalytic oxygen evolution measured by the above-synthesized catalyst in a three-electrode system.

[0050] Among them, the first catalyst represents the catalyst synthesized in Example 1, the second catalyst represents the catalyst synthesized in Example 2, and the third catalyst represents the catalyst synthesized in Example 5.

[0051] Figure 3 The X-ray photoelectron spectroscopy diagram of the Ir group clusters prepared in Example 1 of the present invention indicates that the electronic structure of the Ir clusters synthesized by this method is not in the metallic state but in the oxidized state.

[0052] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of a supported Ir group cluster catalyst, characterized in that It includes the following steps: (1) Immerse the support in an Ir precursor solution; (2) Take out the support, and then perform heat treatment on the support to obtain a supported Ir group cluster catalyst; The support described in step (1) is Ni-Mo-P grown on carbon paper, and its preparation steps are as follows: First, dissolve 5 mmol / L nickel chloride and 1 mmol / L ammonium molybdate completely in 60 mL of deionized water, and then add 22.5 mmol / L urea to the mixed solution; after continuous stirring for 1 h, a uniform green solution is obtained; then, put the above uniform green solution and carbon paper into a 100 mL polytetrafluoroethylene-lined stainless steel hydrothermal autoclave, and anneal at 120 °C in an incubator for 6 h; after the hydrothermal method is completed, wash the obtained Ni-Mo precursor with water and ethanol repeatedly, and dry it overnight in a furnace at 60 °C, and the obtained sample is Ni-Mo / CP; put 0.5 g of the synthesized Ni-Mo / CP and 1 g of sodium hypophosphite powder into two crucibles respectively. In order to obtain effective phosphating treatment, place the crucible with sodium hypophosphite on the upstream side, and the distance between the two crucibles is 5 cm; then, carry out a 1-hour phosphorylation reaction under a N2 flow at 550 °C, and successfully synthesize Ni-Mo-P grown on carbon paper; The heating atmosphere of the heat treatment described in step (2) is one or a mixture of at least two of nitrogen, argon, ammonia, and helium; In the supported Ir group cluster catalyst, the Ir cluster is in an oxidized state; the size of the Ir group cluster in the supported Ir group cluster catalyst is 0.1 - 10 nanometers.

2. The preparation method of the supported Ir group cluster catalyst according to claim 1, characterized in that: The Ir precursor described in step (1) includes at least one of iridium chloride, chloroiridic acid, iridium acetate, ammonium chloroiridate, potassium chloroiridate, and sodium chloroiridate.

3. The preparation method of the supported Ir group cluster catalyst according to claim 1, characterized in that: The solvent of the Ir precursor solution described in step (1) includes at least one of water, ethanol, ethylene glycol, acetone, chloroform, and dimethylformamide; The concentration of the Ir precursor solution described in step (1) is 0.00001 - 10.0 mol / L.

4. The preparation method of the supported Ir group cluster catalyst according to claim 1, characterized in that: The immersion time described in step (1) is 10 min - 48 h, and the impregnation occurs at room temperature.

5. The preparation method of the supported Ir group cluster catalyst according to claim 1, wherein: The heating temperature of the heat treatment described in step (2) is 150 - 600 °C; the heating time is 30 min - 30 h.

6. A supported Ir group cluster catalyst prepared by the method according to any one of claims 1 - 5.

7. The catalyst of the supported Ir group cluster according to claim 6, characterized in that: The size of the Ir group cluster is 0.1 - 1.2 nanometers.

8. The application of the supported Ir group cluster catalyst according to claim 6 or 7 in the field of energy storage.

9. The application of the supported Ir group cluster catalyst according to claim 6 or 7 in electrocatalytic oxygen evolution.

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