Acidic oxygen evolution electrocatalyst as well as preparation method and application thereof

Abstract

The invention provides an acidic oxygen evolution electrocatalyst as well as a preparation method and application thereof. The acidic oxygen evolution electrocatalyst comprises a carrier and an active component loaded in the carrier, the carrier comprises a rare earth element doped transition metal oxide, and the active component comprises a noble metal. The acidic oxygen evolution electrocatalyst provided by the invention can obtain higher OER activity and stability while greatly reducing the use amount of noble metal, can stably run for 22 hours under the current density of 10mA cm <-2 >, and can still keep a complete morphology structure after an OER test. In addition, the preparation method is simple and suitable for large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalyst preparation, and relates to an acidic oxygen evolution electrocatalyst and a preparation method and application thereof. Background Art

[0002] At present, the use of fossil fuels still accounts for a large proportion in human society. Their mining and burning will increase the speed of global warming and accelerate the frequency of extreme climate. Affected by this, the world's energy structure is facing profound adjustments, and energy transformation is imminent. As we all know, hydrogen energy has the advantages of efficient emission reduction, abundant reserves, and wide sources. It has been considered as an ideal clean energy carrier. Therefore, it is of great significance to develop efficient and green hydrogen production technology. At present, water electrolysis hydrogen production technology powered by renewable energy is considered to be an environmentally friendly and promising way to produce green hydrogen.

[0003] Among the many water electrolysis technologies, the proton exchange membrane (PEM) system has gradually become the development trend in the field of electrolytic hydrogen production due to its advantages of high current density, high hydrogen purity (≥99.99%), fast response, and prevention of gas crossover. However, due to the acidic environment, high anode potential, and good conductivity of PEM water electrolysis hydrogen production, expensive and non-large-scale metal Ir, Ru, and Rh-based materials are currently known electrocatalysts that can balance OER activity and stability in acidic electrolytes.

[0004] At present, balancing the OER activity and stability of noble metal-based catalysts and reducing the amount of noble metals are of great significance for accelerating the rate of hydrogen production from PEM water electrolysis and reducing the cost of hydrogen production. In fact, supported electrocatalysts can significantly reduce the amount of noble metals, enhance the dispersion of active phases, provide high surface area and a large number of catalytic sites for oxygen evolution reaction. The activity and stability of the catalyst can be significantly improved through metal-support interaction. Therefore, the development of supported catalysts with low noble metal loading is of great significance for the practical application of PEM water electrolysis.

[0005] Recently, the nanorod-shaped Ru-clusters / α-MnO2 electrocatalysts synthesized by Zhao et al. showed good acidic OER electrocatalytic activity, in which the Ru loading was 10wt%; at the same time, the Ru nanoparticles supported on tantalum-cerium bimetallic oxide synthesized by Lu et al. had a mass percentage of precious metal iridium between 30 and 40%.

[0006] However, the content of noble metals in the above catalysts is still higher than 10wt%, and the preparation process of the catalysts is relatively complicated. There are still great challenges in practical application and large-scale preparation, and the cost of preparing the catalysts is high. Therefore, it is a technical problem to be solved urgently to provide a noble metal-based catalyst and a simple preparation method thereof, further reduce the loading of noble metals to less than 10wt%, and have good acidic OER electrocatalytic activity and stability, suitable for large-scale production and preparation. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide an acidic oxygen evolution electrocatalyst and its preparation method and application. The acidic oxygen evolution electrocatalyst provided by the present invention can significantly reduce the amount of precious metals while obtaining higher OER activity and stability. -2 At a current density of , the overpotential can be as low as 243 mV, and it can operate stably for 22 hours. After the OER test, it can still maintain a good morphology and structure. In addition, the preparation method of the present invention is simple and suitable for large-scale production.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides an acidic oxygen evolution electrocatalyst, comprising a carrier and an active component loaded in the carrier, wherein the carrier comprises a transition metal oxide doped with a rare earth element, and the active component comprises a noble metal.

[0010] The acidic oxygen evolution electrocatalyst provided by the present invention improves its electrocatalytic oxygen evolution activity by doping rare earth elements and loading precious metals into transition metal oxides, so that the rare earth elements and precious metal elements occupy part of the atomic sites of the transition metal elements, and utilizes the synergistic effect among the three, thereby greatly improving its electrochemical performance in the electrocatalytic oxygen evolution reaction process.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0012] Preferably, the rare earth element includes any one of La, Ce, Pr, Nd, Sm or Eu, or a combination of at least two thereof, preferably La.

[0013] Preferably, the transition metal includes any one of Co, Ni, Fe or Mn or a combination of at least two thereof, preferably Co.

[0014] Preferably, the noble metal includes any one of Ru, Ir or Rh or a combination of at least two thereof, preferably Ru.

[0015] The acidic oxygen evolution electrocatalyst provided by the present invention further selects Ru to be loaded on a La-doped Co3O4 carrier. Due to La doping, the d-band centers of Co and Ru are reduced, the adsorption and desorption of oxygen intermediates are optimized, and the oxygen evolution performance of the catalyst is further improved.

[0016] Preferably, the mass proportion of the precious metal in the acidic oxygen evolution catalyst is 1% to 10%, preferably 1% to 5%, for example 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In the present invention, the electrocatalytic performance can be controlled by adjusting the loading amount of the noble metal. When the loading amount of the noble metal is within the range of 1% to 10%, the balance between the catalyst performance and the cost can be achieved. If the loading amount is too low, the sites occupied by the noble metal elements are relatively small, which is not conducive to improving the activity; if the loading amount is too high, the cost will increase.

[0018] Preferably, the mass proportion of the rare earth element in the acidic oxygen evolution catalyst is 1% to 10%, preferably 1% to 5%, for example 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] In the present invention, by adjusting the doping amount of rare earth elements and controlling it within the range of 1% to 10%, the synergistic effect between rare earth elements and precious metal elements and transition metal elements can be better exerted, and the electronic structure and d-band center of Co and Ru can be better regulated.

[0020] Preferably, the morphology of the acidic oxygen evolution electrocatalyst comprises a rhombic dodecahedron.

[0021] In the present invention, the morphology of the rhombic dodecahedron can further increase the specific surface area of ​​the catalyst, increase its active sites, and thus improve the activity of the catalyst.

[0022] In a second aspect, the present invention further provides a method for preparing an acidic oxygen evolution electrocatalyst, comprising the following steps:

[0023] A transition metal oxide carrier doped with a rare earth element is prepared, and then a noble metal is loaded into the carrier to obtain the acidic oxygen evolution electrocatalyst.

[0024] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0025] Preferably, the method for preparing the carrier comprises:

[0026] The organic ligand, transition metal salt and rare earth metal salt are mixed, and after complexation reaction, first calcination is performed to obtain the carrier.

[0027] Preferably, the organic ligand comprises an imidazole compound, and the imidazole compound comprises 2-methylimidazole and / or 2-aminoimidazole.

[0028] In the present invention, by using imidazole compounds and utilizing the complexation between imidazole compounds and transition metal ions, the morphology of rhombic dodecahedron can be better formed.

[0029] Preferably, the transition metal salt includes any one of cobalt salt, nickel salt, iron salt or manganese salt, or a combination of at least two thereof.

[0030] Preferably, the cobalt salt includes any one of cobalt nitrate, cobalt chloride or cobalt sulfate, or a combination of at least two of them.

[0031] Preferably, the rare earth metal salt includes any one of lanthanum salt, cerium salt, praseodymium salt, neodymium salt, samarium salt or europium salt, or a combination of at least two of them.

[0032] Preferably, the lanthanum salt comprises any one of lanthanum nitrate, lanthanum acetate or lanthanum carbonate, or a combination of at least two thereof.

[0033] Preferably, the mass ratio of the transition metal salt to the rare earth metal salt is 1:(0.3-1.6), preferably 1:(0.3-0.8), for example 1:0.3, 1:0.5, 1:0.7, 1:0.8, 1:1.0, 1:1.2, 1:1.4 or 1:1.6, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the organic ligand is dissolved to obtain a first solution, and the transition metal salt and the noble metal salt are dissolved to obtain a second solution.

[0035] Preferably, the mixing comprises adding the second solution to the first solution.

[0036] In the present invention, by controlling the order of adding materials, it is more conducive to the preparation of rhombic dodecahedron morphology.

[0037] Preferably, the complexing reaction includes stirring and aging.

[0038] Preferably, the stirring temperature is 20-30°C, for example 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the stirring time is 10 to 30 min, for example, 10 min, 15 min, 20 min, 25 min or 30 min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the aging time is 10 to 14 hours, for example 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours or 14 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the aged product is washed and dried.

[0042] Preferably, the washing solvent includes any one of water or alcohol solvents or a combination of at least two of them.

[0043] Preferably, the alcohol solvent includes methanol.

[0044] Preferably, the temperature of the first calcination is 200-400°C, such as 200°C, 250°C, 300°C, 350°C or 400°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] Preferably, the heating rate of the first calcination is 2-4°C / min, for example, 2°C / min, 2.5°C / min, 3°C / min, 3.5°C / min or 4°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In the present invention, by regulating the first calcination temperature and the first calcination heating rate, it is more conducive to maintaining the product morphology.

[0047] Preferably, the first calcination time is 4 to 8 hours, for example 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] Preferably, the first calcination atmosphere includes an air atmosphere.

[0049] Preferably, the method of loading the noble metal into the carrier comprises: dispersing a noble metal salt into the carrier, and performing a second calcination after the reaction to obtain the acidic oxygen evolution electrocatalyst.

[0050] Preferably, the noble metal salt comprises a ruthenium salt, and the ruthenium salt comprises any one of ruthenium chloride, ruthenium nitrate or ruthenium oxalate, or a combination of at least two thereof.

[0051] Preferably, the mass ratio of the carrier to the noble metal salt is 100:(5-30), for example 100:5, 100:10, 100:15, 100:20, 100:25 or 100:30, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] Preferably, the dispersing solvent comprises deionized water.

[0053] Preferably, the dispersion method includes ultrasound.

[0054] Preferably, the reaction temperature is 50-70°C, such as 50°C, 55°C, 60°C, 65°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, the reaction time is 10 to 14 h, for example 10 h, 10.5 h, 11 h, 11.5 h, 12 h, 12.5 h, 13 h, 13.5 h or 14 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] Preferably, the product after the reaction is completed is washed and dried.

[0057] Preferably, the temperature of the second calcination is 200-300°C, for example, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C or 300°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] Preferably, the heating rate of the second calcination is 4 to 8°C / min, for example, 4°C / min, 4.5°C / min, 5°C / min, 5.5°C / min, 6°C / min, 6.5°C / min, 7°C / min, 7.5°C / min or 8°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] Preferably, the second calcination time is 2 to 4 hours, such as 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] Preferably, the atmosphere of the second calcination includes an air atmosphere.

[0061] As a preferred technical solution, the preparation method comprises the following steps:

[0062] (1) dissolving a transition metal salt and a rare earth metal salt in a mass ratio of 1:(0.3-0.8) and adding the mixture to an imidazole compound organic ligand solution, stirring the mixture at 20-30° C. for 10-30 min, aging the mixture for 10-14 h, washing and drying the mixture, heating the mixture to 200-400° C. at a heating rate of 2-4° C. / min in an air atmosphere, and maintaining the temperature for 4-8 h to obtain a rare earth element-doped transition metal oxide support;

[0063] (2) placing the carrier in deionized water, adding a noble metal salt in a mass ratio of the carrier to the noble metal salt of 100:(5-30), ultrasonically dispersing, and then reacting at 50-70° C. for 10-14 hours. After washing and drying, heating to 200-300° C. at a heating rate of 4-8° C. / min in an air atmosphere, and keeping the temperature for 2-4 hours, to obtain the acidic oxygen evolution electrocatalyst;

[0064] The imidazole compounds include 2-methylimidazole and / or 2-aminoimidazole.

[0065] In a third aspect, the present invention further provides a use of an acidic oxygen evolution electrocatalyst, which includes using the acidic oxygen evolution electrocatalyst as described in the first aspect or the acidic oxygen evolution catalyst prepared by the preparation method described in any one of the second aspects in an electrocatalytic oxygen evolution reaction.

[0066] Compared with the prior art, the present invention has the following beneficial effects:

[0067] The acidic oxygen evolution electrocatalyst provided by the present invention is to dope rare earth elements in transition metal oxides and load precious metals, so that rare earth elements and precious metal elements occupy part of the atomic sites of transition metal elements, and utilize the synergistic effect among the three, while greatly reducing the amount of precious metals, obtain higher OER activity and stability, and at 10 mA cm -2 At a current density of , the overpotential can be as low as 243mV, and it can run stably for 22 hours. After the OER test, it can still maintain a good morphology and structure. In addition, the preparation method of the present invention is simple and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 1 is the XRD diagram of the acidic oxygen evolution electrocatalyst prepared in Example 1 and Examples 7-9.

[0069] Figure 2 is a SEM image of the acidic oxygen evolution electrocatalyst prepared in Example 1.

[0070] Figure 3 This is a TEM image of the acidic oxygen evolution electrocatalyst prepared in Example 1.

[0071] Figure 4 This is the HRTEM image of the acidic oxygen evolution electrocatalyst in Example 1.

[0072] Figure 5 This is the mapping diagram of the acidic oxygen evolution electrocatalyst prepared in Example 1.

[0073] Figure 6 It is the linear voltammetric curve of the acidic oxygen evolution electrocatalyst prepared in Example 1 and Examples 7-9.

[0074] Figure 7 This is the XRD diagram of the Ru@Co3O4 material prepared in Comparative Example 1.

[0075] Figure 8 The linear voltammetric curves of the Ru@Co3O4 material prepared in Example 1 and commercial RuO2 are shown.

[0076] Fig. 9 It is a stability test chart of the acidic oxygen evolution electrocatalyst and commercial RuO2 prepared in Example 1 and Examples 7-9.

[0077] Fig.10 This is a stability test diagram of the Ru@Co3O4 material prepared in Example 1. DETAILED DESCRIPTION

[0078] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0079] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0080] Example 1

[0081] This embodiment provides a method for synthesizing a Ru@La / Co3O4 acidic oxygen evolution electrocatalyst, comprising the following steps:

[0082] (1) Weigh a certain amount of 2.25 g 2-methylimidazole, 1.00 g Co(NO3)2·6H2O and 0.53 g La(NO3)3·6H2O, dissolve 2-methylimidazole in an appropriate amount of methanol to obtain solution A; then dissolve Co(NO3)2·6H2O and La(NO3)3·6H2O in an appropriate amount of methanol to obtain solution B; add solution B to solution A, stir at room temperature for 20 min, and then age for 12 h; finally wash with methanol and dry to obtain La-doped ZIF-67 rhombic dodecahedron;

[0083] (2) placing the obtained La-doped ZIF-67 rhombic dodecahedron in a muffle furnace and calcining it at 360°C for 6 h to prepare La-doped Co3O4 material;

[0084] (3) 100 mg of the La-doped Co3O4 material was placed in an appropriate amount of deionized water, 20 mg of RuCl3·xH2O was added, and after ultrasonic dispersion, the mixture was reacted at 60°C for 12 h, and then washed with deionized water and dried;

[0085] (4) The material obtained in (3) was placed in a muffle furnace and calcined at 250°C for 3 h to obtain a Ru@La / Co3O4 acidic oxygen evolution electrocatalyst.

[0086] The Ru@La / Co3O4 acidic oxygen evolution electrocatalyst prepared in this example is named Ru@La / Co3O4-20 (Ru content is 2.5wt%), and its XRD pattern is shown in Figure 1 , and its XRD peak position is consistent with the standard Co3O4 XRD.

[0087] The SEM and TEM images of the Ru@La / Co3O4 acidic oxygen evolution electrocatalyst prepared in this example are shown in Figure 2 and Figure 3 As shown by Figure 2 and Figure 3 It can be seen that the catalyst retains the morphology of ZIF-67 rhombic dodecahedron.

[0088] The HRTEM of Ru@La / Co3O4 acidic oxygen evolution electrocatalyst prepared in this example is as follows Figure 4 As shown, the lattice fringe spacing coincides with the crystal plane of Co3O4.

[0089] The mapping diagram of the Ru@La / Co3O4 acidic oxygen evolution electrocatalyst prepared in this example is shown in Figure 5 As shown, it shows that La, Ru, Co and O atoms are evenly distributed in the crystal structure.

[0090] Example 2

[0091] This embodiment provides a method for synthesizing an Ir@Ce / NiO acidic oxygen evolution electrocatalyst, comprising the following steps:

[0092] (1) Weigh a certain amount of 2.25 g 2-methylimidazole, 1.00 g Ni(NO3)3·6H2O and 0.3 g Ce(NO3)3·6H2O, dissolve 2-methylimidazole in an appropriate amount of methanol to obtain solution A; then dissolve Ni(NO3)3·6H2O and Ce(NO3)3·6H2O in an appropriate amount of methanol to obtain solution B; add solution B to solution A, stir at 20°C for 10 min, and then age for 10 h; finally wash with methanol and dry to obtain Ce-doped ZIF-67 rhombic dodecahedron;

[0093] (2) placing the obtained Ce-doped ZIF-67 rhombic dodecahedron in a muffle furnace and calcining it at 200° C. for 4 h to prepare a Ce-doped NiO material;

[0094] (3) 100 mg of the obtained Ce-doped NiO material was placed in an appropriate amount of deionized water, 10 mg of IrCl3·xH2O was added, and after ultrasonic dispersion, the mixture was reacted at 50°C for 10 h, and then washed with deionized water and dried;

[0095] (4) The material obtained in (3) was placed in a muffle furnace and calcined at 200° C. for 2 h to obtain an Ir@Ce / NiO acidic oxygen evolution electrocatalyst.

[0096] The Ir@Ce / NiO acidic oxygen evolution electrocatalyst prepared in this example is named Ir@Ce / NiO-5.

[0097] Example 3

[0098] This embodiment provides a method for synthesizing a Rh@Eu / MnO2 acidic oxygen evolution electrocatalyst, comprising the following steps:

[0099] (1) Weigh a certain amount of 2.25 g 2-methylimidazole, 1.00 g MnCl2·6H2O and 1.6 g Eu(NO3)3·6H2O, dissolve 2-methylimidazole in an appropriate amount of methanol to obtain solution A; then dissolve MnCl2·6H2O and Eu(NO3)3·6H2O in an appropriate amount of methanol to obtain solution B; add solution B to solution A, stir at 30°C for 30 min, and then age for 14 h; finally wash with methanol and dry to obtain Eu-doped ZIF-67 rhombic dodecahedron;

[0100] (2) placing the obtained Eu-doped ZIF-67 rhombic dodecahedron in a muffle furnace and calcining it at 400°C for 8 h to prepare Eu-doped MnO2 material;

[0101] (3) 100 mg of the obtained Eu-doped MnO2 material was placed in an appropriate amount of deionized water, 60 mg of RhCl3·xH2O was added, and after ultrasonic dispersion, the mixture was reacted at 70°C for 14 h, and then washed with deionized water and dried;

[0102] (4) The material obtained in (3) was placed in a muffle furnace and calcined at 300°C for 4 hours to obtain a Rh@Eu / MnO2 acidic oxygen evolution electrocatalyst.

[0103] The Rh@Eu / MnO2 acidic oxygen evolution electrocatalyst prepared in this example is named Rh@Eu / MnO2-60.

[0104] Example 4

[0105] The difference between this embodiment and embodiment 1 is that 1.2 g La(NO3)3·6H2O is added in step (1).

[0106] The rest of the preparation methods and parameters were the same as those in Example 1.

[0107] Example 5

[0108] The difference between this embodiment and embodiment 1 is that 0.15 g La(NO3)3·6H2O is added in step (1).

[0109] The rest of the preparation methods and parameters were the same as those in Example 1.

[0110] Example 6

[0111] The difference between this embodiment and embodiment 1 is that 2.0 g La(NO3)3·6H2O is added in step (1).

[0112] The rest of the preparation methods and parameters were the same as those in Example 1.

[0113] Example 7

[0114] The difference between this embodiment and embodiment 1 is that 10 mg of RuCl 3 ·xH 2 O is added in step (3).

[0115] The rest of the preparation methods and parameters were the same as those in Example 1.

[0116] The Ru@La / Co3O4 acidic oxygen evolution electrocatalyst prepared in this example is named Ru@La / Co3O4-10 (Ru content is 1.7wt%), and its XRD pattern is shown in Figure 1 , and its XRD peak position is consistent with the standard Co3O4 XRD.

[0117] Example 8

[0118] The difference between this embodiment and embodiment 1 is that 15 mg of RuCl 3 ·xH 2 O is added in step (3).

[0119] The rest of the preparation methods and parameters were the same as those in Example 1.

[0120] The Ru@La / Co3O4 acidic oxygen evolution electrocatalyst prepared in this example is named Ru@La / Co3O4-15 (Ru content is 2.1wt%), and its XRD pattern is shown in Figure 1 , and its XRD peak position is consistent with the standard Co3O4 XRD.

[0121] Example 9

[0122] The difference between this embodiment and embodiment 1 is that 25 mg of RuCl3·xH2O is added in step (3).

[0123] The rest of the preparation methods and parameters were the same as those in Example 1.

[0124] The Ru@La / Co3O4 acidic oxygen evolution electrocatalyst prepared in this example is named Ru@La / Co3O4-25 (Ru content is 2.7wt%), and its XRD pattern is shown in Figure 1 , and its XRD peak position is consistent with the standard Co3O4 XRD.

[0125] Example 10

[0126] The difference between this embodiment and embodiment 1 is that 50 mg of RuCl3·xH2O is added in step (3).

[0127] The rest of the preparation methods and parameters were the same as those in Example 1.

[0128] Embodiment 11

[0129] The difference between this embodiment and embodiment 1 is that 2 mg of RuCl 3 ·xH 2 O is added in step (3).

[0130] The rest of the preparation methods and parameters were the same as those in Example 1.

[0131] Example 12

[0132] The difference between this embodiment and embodiment 1 is that 70 mg of RuCl 3 ·xH 2 O is added in step (3).

[0133] The rest of the preparation methods and parameters were the same as those in Example 1.

[0134] Comparative Example 1

[0135] The difference between this comparative example and Example 1 is that La(NO3)3·6H2O is not added in step (1).

[0136] The rest of the preparation methods and parameters were the same as those in Example 1.

[0137] Figure 7 The XRD pattern of the Ru@Co3O4 material prepared in Comparative Example 1 is shown. Figure 7 It can be seen that the peak position of its XRD is consistent with that of standard Co3O4 XRD.

[0138] Comparative Example 2

[0139] The difference between this comparative example and Example 1 is that in step (1), 0.53 g La(NO3)3·6H2O and 20 mg RuCl3·xH2O are added simultaneously, and steps (3) and (4) are not performed.

[0140] The rest of the preparation methods and parameters were the same as those in Example 1.

[0141] Comparative Example 3

[0142] The difference between this comparative example and Example 1 is that La(NO3)3·6H2O in step (1) is replaced by Fe(NO3)3·9H2O.

[0143] The rest of the preparation methods and parameters were the same as those in Example 1.

[0144] Performance Test:

[0145] The acidic oxygen evolution electrocatalysts prepared in Examples 1-12 and Comparative Examples 1-3 and commercially available RuO2 were used as catalysts to perform acidic OER performance tests. The test method is as follows:

[0146] (1) First, a catalyst ink was prepared. The specific preparation method was as follows: 5 mg of the catalyst was added to a mixed solution containing 20 μl of Nafion and 980 μl of ethanol, and then ultrasonicated for 30 minutes to obtain a uniform black catalyst ink.

[0147] (2) Pipette 100 μl of the ink onto a surface area of ​​1 cm 2 The working electrode film was formed on the carbon paper and dried at room temperature.

[0148] (3) A three-electrode cell test was performed with a platinum electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and 0.5 M H2SO4 as the electrolyte. The test voltage range was 1.0–2.0 V vs. RHE. A linear voltammetric curve was obtained and the current density was recorded up to 10 mA cm -2 overpotential; test the stability of the catalyst.

[0149] The test results are shown in Table 1 and the attached figure:

[0150] Table 1

[0151]

[0152]

[0153] As shown in Table 1, the acidic oxygen evolution electrocatalysts prepared in Examples 1-3 have a -2 At a current density of , the overpotentials are 243mV, 272mV, and 260mV, respectively, and can stably operate for about 22 hours at this current density. This shows that, thanks to the synergistic effect between rare earth element doping and precious metal loading, the present invention not only reduces the amount of precious metals used, but also greatly improves the activity of precious metals, making it exhibit more excellent electrochemical oxygen evolution performance.

[0154] Depend on Figure 6 , Figure 8 As shown in Table 1, Example 1 (Ru@La / Co3O4-20) has a -2 The overpotential is 243 mV at a current density of 10 mA cm -2 The overpotential at the current density of 200 mA cm-1 is 295 mV, which is significantly higher than that of Example 1. It can be seen that doping rare earth elements on the transition metal oxide support can significantly improve the activity of the precious metal. -2 The overpotential at the current density of 280 mV is also lower than that of Example 1, which shows that the oxygen evolution catalyst obtained by the preparation process of first doping and then loading in the present invention further improves the activity of the precious metal due to the strong interaction of the metal carrier compared with the direct preparation of the alloy by one-step doping; Comparative Example 3 at 10 mA cm -2 The overpotential at the current density is 278 mV, which is also lower than that in Example 1. This shows that the transition metal elements, rare earth elements and precious metals in the present invention interact and cooperate with each other. Replacing any one of them will reduce the activity of the catalyst, which is not conducive to improving the oxygen evolution performance of the catalyst.

[0155] Depend on Fig. 9 and Fig.10 It can be seen that Example 1 and Comparative Example 1 have a -2 They can all run stably for about 22 hours at a current density of , while commercial RuO2 will be deactivated after running for 7 hours. It can be seen that the preparation method of the present invention is used to load precious metals on transition metal oxides, which can significantly improve the electrochemical stability of the precious metals. At the same time, it can also be seen that the degradation rate of Example 1 is 8.4 mV / h, and the degradation rate of Comparative Example 1 is 14 mV / h, and the degradation rate is significantly accelerated. It can be seen that doping rare earth elements in transition metal oxides can further improve the stability of precious metals.

[0156] It can be seen from Table 1 that Example 4 and Example 10 have a -2 At a current density of , the overpotentials are 255 mV and 257 mV, respectively, which are both lower than those in Example 1. This shows that when the mass ratio of the transition metal salt to the rare earth metal salt is controlled at 1:(0.3-0.8) and the mass ratio of the carrier to the noble metal salt is controlled at 100:(5-30) in the present invention, the La doping amount and the Ru loading amount in the prepared acidic oxygen evolution electrocatalyst are roughly between 1% and 5%, and the catalyst has better electrochemical performance.

[0157] It can be seen from Table 1 that the acidic oxygen evolution electrocatalysts prepared in Example 5 and Example 6 have a high conductivity at 10 mA cm -2 At a current density of , the overpotentials are 269 mV and 265 mV, respectively, both of which are lower than those in Example 1. This indicates that controlling the doping amount of rare earth elements to 1-10% is more conducive to the synergistic effect between rare earth elements and precious metals.

[0158] Depend on Figure 6 , Figure 8 As shown in Table 1, the acidic oxygen evolution electrocatalysts prepared in Examples 7-9 have a -2 At a current density of , the overpotentials are 270 mV, 262 mV and 254 mV, respectively, and those of Example 11 and Example 12 are 275 mV and 262 mV, respectively, which indicates that the electrocatalytic oxygen evolution activity can be adjusted by regulating the loading amount of Ru; and when the loading amount of Ru is in the range of 1 to 10%, the lattice structure of the transition metal oxide can be better adjusted, which is more conducive to the improvement of the catalyst activity.

[0159] At the same time, the acidic oxygen evolution electrocatalyst provided by the present invention has excellent structural stability, and its morphology and structure remain intact after OER testing.

[0160] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. An acidic oxygen evolution electrocatalyst, characterized in that The acidic oxygen evolution catalyst comprises a carrier and an active component loaded in the carrier, wherein the carrier comprises a transition metal oxide doped with a rare earth element, and the active component comprises a noble metal.

2. The acidic oxygen evolution electrocatalyst according to claim 1, characterized in that The rare earth element includes any one or a combination of at least two of La, Ce, Pr, Nd, Sm or Eu, preferably La; Preferably, the transition metal comprises any one or a combination of at least two of Co, Ni, Fe or Mn, preferably Co; Preferably, the noble metal includes any one of Ru, Ir or Rh or a combination of at least two thereof, preferably Ru.

3. The acidic oxygen evolution electrocatalyst according to claim 1 or 2, characterized in that: The mass proportion of the noble metal in the acidic oxygen evolution catalyst is 1% to 10%, preferably 1% to 5%; Preferably, the mass proportion of the rare earth element in the acidic oxygen evolution catalyst is 1% to 10%, preferably 1% to 5%; Preferably, the morphology of the acidic oxygen evolution electrocatalyst comprises a rhombic dodecahedron.

4. A method for preparing an acidic oxygen evolution electrocatalyst according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: A transition metal oxide carrier doped with a rare earth element is prepared, and then a noble metal is loaded into the carrier to obtain the acidic oxygen evolution electrocatalyst.

5. The method for preparing an acidic oxygen evolution electrocatalyst according to claim 4, characterized in that: The preparation method of the carrier comprises: Mixing an organic ligand, a transition metal salt and a rare earth metal salt, and performing a first calcination after a complexation reaction to obtain the carrier; Preferably, the organic ligand comprises an imidazole compound, and the imidazole compound comprises 2-methylimidazole and / or 2-aminoimidazole; Preferably, the transition metal salt comprises any one of cobalt salt, nickel salt, iron salt or manganese salt, or a combination of at least two thereof; Preferably, the rare earth metal salt comprises any one or a combination of at least two of lanthanum salt, cerium salt, praseodymium salt, neodymium salt, samarium salt or europium salt; Preferably, the mass ratio of the transition metal salt to the rare earth metal salt is 1:(0.3-1.6), preferably 1:(0.3-0.8).

6. The method for preparing an acidic oxygen evolution electrocatalyst according to claim 5, characterized in that: The organic ligand is dissolved to obtain a first solution, and the transition metal salt and the noble metal salt are dissolved to obtain a second solution; Preferably, the mixing comprises adding the second solution to the first solution; Preferably, the complexing reaction includes stirring and aging; Preferably, the stirring temperature is 20 to 30°C; Preferably, the stirring time is 10 to 30 minutes; Preferably, the aging time is 10 to 14 hours; Preferably, the aged product is washed and dried; Preferably, the washing solvent includes any one of water or alcohol solvents or a combination of at least two; Preferably, the alcohol solvent includes methanol; Preferably, the temperature of the first calcination is 200-400°C; Preferably, the heating rate of the first calcination is 2-4°C / min; Preferably, the first calcination time is 4 to 8 hours; Preferably, the first calcination atmosphere includes an air atmosphere.

7. The method for preparing an acidic oxygen evolution electrocatalyst according to any one of claims 4 to 6, characterized in that: The method of loading the noble metal in the carrier comprises: dispersing the noble metal salt in the carrier, and performing a second calcination after the reaction to obtain the acidic oxygen evolution electrocatalyst; Preferably, the mass ratio of the carrier to the noble metal salt is 100:(5-60), preferably 100:(5-30).

8. The method for preparing an acidic oxygen evolution electrocatalyst according to claim 7, characterized in that: The dispersed solvent includes deionized water; Preferably, the dispersion method includes ultrasound; Preferably, the reaction temperature is 50-70°C; Preferably, the reaction time is 10 to 14 hours; Preferably, the product after the reaction is completed is washed and dried; Preferably, the temperature of the second calcination is 200-300°C; Preferably, the heating rate of the second calcination is 4-8°C / min; Preferably, the second calcination time is 2 to 4 hours; Preferably, the atmosphere of the second calcination includes an air atmosphere.

9. The method for preparing an acidic oxygen evolution electrocatalyst according to claim 4, characterized in that: The preparation method comprises: (1) dissolving a transition metal salt and a rare earth metal salt in a mass ratio of 1:(0.3-0.8) and adding the mixture to an imidazole compound organic ligand solution, stirring the mixture at 20-30° C. for 10-30 min, aging the mixture for 10-14 h, washing and drying the mixture, heating the mixture to 200-400° C. at a heating rate of 2-4° C. / min in an air atmosphere, and maintaining the temperature for 4-8 h to obtain a rare earth element-doped transition metal oxide support; (2) placing the carrier in deionized water, adding a noble metal salt in a mass ratio of the carrier to the noble metal salt of 100:(5-30), ultrasonically dispersing, and then reacting at 50-70° C. for 10-14 hours. After washing and drying, heating to 200-300° C. at a heating rate of 4-8° C. / min in an air atmosphere, and keeping the temperature for 2-4 hours, to obtain the acidic oxygen evolution electrocatalyst; The imidazole compounds include 2-methylimidazole and / or 2-aminoimidazole.

10. Use of an acidic oxygen evolution electrocatalyst, characterized in that: The use includes using the acidic oxygen evolution electrocatalyst described in any one of claims 1 to 3 or the acidic oxygen evolution catalyst prepared by the preparation method described in any one of claims 4 to 9 in an electrocatalytic oxygen evolution reaction.

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