CN116555809A - A kind of HER electrocatalyst and preparation method thereof - Google Patents

Abstract

The invention relates to a HER electrocatalyst and a preparation method thereof, and belongs to the field of catalysts. The invention provides a preparation method of an HER electrocatalyst, which comprises the following steps: dispersing rhodium salt or iridium salt in an alcohol solvent to form a stable and transparent solution, adding a nitrogen-containing substance into the solution, and stirring to dissolve the nitrogen-containing substance; adding the carbon substrate, and stirring and uniformly mixing; then standing, aging and complexing the obtained reaction system to obtain gel-like solid; and then placing the obtained gel-like solid in an inert gas environment, heating for 2-5 h at 65-75 ℃, then heating to 500-800 ℃ and keeping the temperature for 2-3 h, finally cooling to room temperature and standing for 1-2 h to obtain the HER electrocatalyst. The invention develops a novel N-doped carbon carrier loaded Rh or Ir nanocluster prepared electrocatalyst, and the obtained electrocatalyst shows excellent HER catalytic activity under a wide pH value range.

Description

A kind of HER electrocatalyst and preparation method thereof

technical field

The invention relates to a HER electrocatalyst and a preparation method thereof, belonging to the field of catalysts.

Background technique

With the increasingly severe energy crisis and environmental pollution, the demand for developing renewable energy is extremely urgent. Among them, hydrogen is considered as one of the most promising options to replace fossil fuels. Hydrogen production by electrocatalytic water splitting is a promising technology that enables the development of global-scale, sustainable, and environmentally friendly energy systems. In HER, noble metal materials (such as Pt-, Pd-, Ir-, and Ru-based materials) are still considered as state-of-the-art catalysts due to their optimal free energy of H* intermediates. However, the scarcity and high price of noble metal materials limit their practical application. Therefore, it remains a challenge to develop highly efficient and low-cost HER catalysts applicable to universal pH conditions.

In order to reduce the usage of noble metals and tune the performance of catalysts, supported metal catalysts have been widely developed to increase metal dispersion and thus maximize the utilization of metal atoms. In electrocatalysis, the support can not only increase the electronic conductivity and expose more active sites, but also induce a synergistic effect and improve the electrocatalytic activity. The synergistic effects between metals and supports, caused by chemical interfacial bonds and charge transfer, can affect the adsorption/desorption behavior of reactants and intermediates, and ultimately affect the electrocatalytic performance. Specifically, the synergistic effect is closely related to the geometric and electronic structures of metals, which can be changed at any time through the coordination engineering of catalytic atoms, thereby affecting the overall reaction kinetics. Local coordination engineering of single-atom catalysts (SACs) is considered to be one of the most effective strategies to optimize catalytic performance. For example, the coordination structure of single copper atomic sites has been reported to have a critical impact on the selectivity and activity of metal catalysts. Although SACs usually suffer from low apparent electrochemical activity and poor stability, the high atomic efficiency and apparent activity of cluster catalysts highlight their great potential for constructing efficient and stable electrocatalysts.

Contents of the invention

The present invention adopts a simple method to construct catalysts containing Rh-N or Ir-N coordinated N-doped carbon-supported Rh or Ir nanoclusters (denoted as Rh _x -NC or Ir _x -NC). Rh _x -NC or Ir _x -NC catalysts show excellent general-purpose HER performance at pH with ultralow overpotential and excellent stability. In 0.5 MH ₂ SO ₄ , 1.0 M KOH and 1.0 MPBS solutions, the overpotentials of Rh _x -NC catalysts were as low as 8, 16 and 109 mV at 10 mA cm ^-2 , respectively. Optimal Rh-N coordination in Rh _x -NCs plays a crucial role in improving the electron transfer, thereby facilitating the generation of H ₂ .

Technical scheme of the present invention:

The first technical problem to be solved in the present invention is to provide a kind of preparation method of HER electrocatalyst, described preparation method is:

Dispersing rhodium salt or iridium salt in an alcoholic solvent to form a stable and transparent solution, then adding nitrogen-containing substances into the solution and stirring to dissolve it;

Then add the carbon substrate and stir to mix;

Then the resulting reaction system is aged and complexed to obtain a gel-like solid;

Then place the obtained gel-like solid in an inert gas environment and heat it at 65-75°C for 2-5 hours, then raise the temperature to 500-800°C for 2-3 hours, and finally cool to room temperature and let it stand for 1-2 hours to obtain the HER electrocatalyst.

Further, the nitrogen-containing substance is urea or melamine.

Further, the carbon substrate is Ketjen black, carbon black, carbon nanotubes or graphene.

Further, the rhodium salt is selected from: RhCl ₃ ·xH ₂ O, Rh(NO ₃ ) ₃ ·xH ₂ O, Rh ₂ (SO ₄ ) ₃ or (NH ₄ ) ₃ RhCl ₆ .

Further, the iridium salt is selected from: IrCl ₃ ·xH ₂ O.

Further, the mass ratio of the rhodium salt to the nitrogen-containing substance is 0.1-10:200.

Further, the mass ratio of the nitrogen-containing substance to the carbon substrate is 10-20:1.

The second technical problem to be solved by the present invention is to provide a HER electrocatalyst, which is prepared by the above method.

Further, the electrocatalyst uniformly supports Rh clusters or Ir clusters on nitrogen-doped carbon supports, and the catalyst contains Rh-N coordination or Ir-N coordination.

Beneficial effects of the present invention:

The present invention prepares a class of electrocatalysts (denoted as Rh _x -NC catalysts or Ir _x -NC catalyst), which provided very high reactivity for HER over a wide pH range, and the resulting Rh _x -NC catalyst required 8 mV and 16 mV in 0.5 M H ₂ SO ₄ , 1.0 M KOH and 1.0 M PBS solutions, respectively. and 109 mV to reach a current density of 10 mA cm ^-2 , which is more advantageous than commercial Rh/C. The resulting Ir _x -NC catalyst has an overpotential of 76 mV at 10 mA cm ^-2 in 1M KOH solution. This work demonstrates the successful coordination of carbon-supported Rh nanoclusters or Ir nanoclusters and provides a new strategy to design nanocluster-based electrocatalysts through coordination chemical engineering for superior HER performance.

Description of drawings

Figure 1: The dark-field TEM image (Figure 1a) of the catalyst Rh _x -NC obtained in Example 1 and the size distribution of Rh clusters (Figure 1b).

Figure 2: HAADF-STEM result map of Rh _x -NC.

Figure 3: EDS element mapping of Rh _x -NC, Figure 3a is the HRTEM dark field image of Rh _x -NC, Figure 3b is the distribution of Rh elements, Figure 3c is the distribution of C elements, and Figure 3d is the distribution of N elements.

Figure 4: a. XRD spectrum of Rh _x -NC; b. Element content analysis of Rh _x -NC; c. XPS spectrum of Rh 3d orbital; d. XPS peak of N 1s orbital.

Figure 5: a. The LSV curve of the catalyst in 1.0 M KOH; b. The overpotential result graph of the catalyst at a current density of 10 mA cm ^-2 ; c. The Tafel slope graph of the catalyst in 1.0 M KOH; d. Catalyst TOF value and mass activity results graph.

Figure 6: a. EIS test result diagram of the catalyst; b. C _dl result diagram of the catalyst.

Fig. 7: Stability test diagram of catalyst Rh _x -NC obtained in Example 1.

Figure 8: a, c. LSV curves of different catalysts; b, d. Tafel slope calculated from the LSV curves in 0.5 MH ₂ SO ₄ , 1.0 M PBS solution.

Figure 9: a, b are the stability test curves in 0.5 MH ₂ SO ₄ and 1.0 M PBS solutions, respectively.

Figure 10: LSV curves of Rh _x /NC in different electrolytes.

Figure 11: LSV curves of catalysts obtained in Examples 2-4 in 1.0 M KOH.

Figure 12: LSV curves of catalysts obtained in Examples 5-7 in 1.0 M KOH.

Figure 13: LSV curve of the catalyst obtained in Example 8 in 1.0 M KOH.

Detailed ways

The present invention adopts a simple method to construct a catalyst containing Rh or Ir nano-clusters loaded on an N-doped carbon carrier containing Rh-N coordination or Ir-N coordination. Rh _x -NC catalysts or Ir _x -NC catalysts show excellent pH-generated HER performance with ultralow overpotential and robust stability. In 0.5 MH ₂ SO ₄ , 1.0 M KOH and 1.0 M PBS solutions, the overpotentials of Rh _x -NC catalysts were as low as 8, 16 and 109 mV at 10 mA cm ^-2 , respectively. The coordination chemistry of the Rh-N molecule affects the charge redistribution between Rh and the support, precisely tunes the geometry and electronic structure of Rh species, optimizes the adsorption energy of reaction intermediates, and ultimately enhances the electrocatalytic performance. Optimal Rh-N coordination in Rh _x -NCs plays a crucial role in improving the electron transfer, thereby facilitating the generation of H ₂ . This work not only makes a breakthrough in the coordination chemical engineering of nanocluster-based electrocatalysts to achieve excellent HER performance, but also provides an in-depth research perspective on the structure-activity structure-activity relationship.

The specific implementation of the present invention will be further described below in conjunction with the examples, and the present invention is not limited to the scope of the examples.

Example 1

Disperse 3 mg of _{RhCl3 xH2O} powder in ethanol (2 mL) to form a stable and transparent solution. Add 200 mg urea to the above solution and stir to dissolve it. Then 20 mg Ketjen Black was added, stirred for 30 minutes, and then transferred to a crucible for aging and complexation for 12 hours to obtain a gel-like solid; the above operations were done in a glove box. Then the gel-like solid was placed in a tube furnace under an argon atmosphere (flow rate 100 mL min ^-1 ), heated to 70 °C at a heating rate of 1 °C/min and kept at a constant temperature for 2 hours, and then heated at a rate of 5 °C/min The heating rate continued to rise to 600°C and kept at a constant temperature for 3 hours, cooled to room temperature and passivated in the same argon flow for 2 hours; the catalyst was obtained after grinding, which was designated as Rh _x -NC.

Example 2-4

The preparation process is the same as in Example 1, except that the mass ratios of RhCl ₃ ·xH ₂ O to urea are 0.5:200 (Example 2), 1:200 (Example 3), and 7.6:200 (Example 4).

Example 5-7

The preparation process is the same as in Example 1, except that the temperature is raised to 500°C and kept at a constant temperature for 3 hours (Example 5), the temperature is raised to 700°C and kept at a constant temperature for 3 hours (Example 6), the temperature is raised to 800°C and kept at a constant temperature for 3 hours ( Example 7).

Example 8

Disperse 3 mg of IrCl ₃ xH ₂ O powder in ethanol (2 mL) to form a stable and transparent solution. Add 200 mg urea to the above solution and stir to dissolve it. Then 20 mg Ketjen Black was added, stirred for 30 minutes, and then transferred to a crucible for aging and complexation for 12 hours to obtain a gel-like solid; the above operations were done in a glove box. Place the gel in a tube furnace under an argon atmosphere (flow rate 100 mL min ^-1 ), heat up to 70 °C at a heating rate of 1 °C/min and keep at a constant temperature for 5 hours, then heat at a rate of 5 °C/min Continue to raise the temperature to 800°C and keep it at a constant temperature for 2 hours, cool to room temperature and passivate in the same argon flow for 2 hours; Ir _x -NC catalyst is obtained after grinding.

Comparative example 1

Preparation of Rh _x -C: Disperse 3 mg RhCl ₃ xH ₂ O powder in ethanol (2 mL) to form a stable and transparent solution. 20 mg Ketjen black was added to the above solution, stirred for 30 minutes, then transferred to a crucible for aging and complexation for 12 hours to obtain a gel-like solid. The above operations were performed in a glove box. Place the gel in a tube furnace under an argon atmosphere (flow rate 100 mL min ^-1 ), heat up to 70 °C at a heating rate of 1 °C/min and keep at a constant temperature for 2 hours, then heat at a heating rate of 5 °C/min Continue to raise the temperature to 600°C and keep it at a constant temperature for 3 hours, cool to room temperature and passivate in the same argon flow for 2 hours; Rh _x -C catalyst is obtained after grinding.

Comparative example 2

Commercial Pt/C was used as comparative example 2, and its brand name was 7440-06-4.

Comparative example 3

Commercial Rh/C was used as comparative example 3, and its brand name was 7440-16-6.

Comparative example 4

Preparation of Rh _x /NC: Disperse 200 mg urea in 2 mL ethanol, add 20 mg Ketjen black to the above solution, stir to disperse evenly, then transfer to a crucible for aging and complexation for 12 hours. The above mixture was placed in a tube furnace under an argon atmosphere (flow rate 100 mL min ^-1 ), heated to 70 °C at a heating rate of 1 °C/min and kept at a constant temperature for 3 hours, and then heated at a rate of 5 °C/min Continue to raise the temperature to 800° C. and keep it at a constant temperature for 2 hours to obtain an NC substrate. The above NCs were dispersed in 5 mL of ethanol, added 3 mg RhCl ₃ xH ₂ O, stirred for 20 minutes, then added dropwise 1 mL of NaBH ₄ aqueous solution (containing 6 mg of NaBH ₄ ), stirred for 30 minutes, washed by centrifugation, and dried in vacuum at 70 °C The product obtained is denoted as Rh _x /NC.

Experimental example 1 Morphological characterization and structural analysis of catalyst Rh _x -NC

The TEM (Fig. 1a) and Rh cluster size map (Fig. 1b) of the Rh _x -NC obtained in Example 1 are shown in Fig. 1. From Fig. 1, it can be seen that the catalyst obtained in the present invention exhibits a unique three-dimensional, porous and spherical structure; The unique morphology of Rh _x -NCs was further investigated by transmission electron microscopy (TEM). TEM images show that Rh nanoclusters are uniformly dispersed in the carbon matrix with an average diameter of about 1.60 nm.

In addition, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) was used to reveal the atomic resolution structure of the Rh _x -NC catalyst obtained in Example 1. High-resolution STEM images, clearly showing the lattice of Rh(111) facets, demonstrate the formation of nanoclusters (Fig. 2). Elemental mapping by energy-dispersive X-ray spectroscopy (EDX) (Fig. 3a–d), confirming the distinct aggregation of Rh and the homogeneous spatial distribution of Rh nanoclusters in the N-doped carbon substrate.

Fig. 4a shows the X-ray diffraction (XRD) pattern of Rh _x -NC obtained in Example 1, taking Rh _x -C (comparative example 1) as a reference. There are two weak and broad diffraction peaks at 25° (002) and 44° (101), which can be attributed to disordered and defective carbon. In addition, no peak of the metallic phase was observed, which is consistent with the results of TEM. To further analyze the composition and electronic structure of Rh _x -NCs, we employed X-ray photoelectron spectroscopy (XPS). The XPS data of Rh _x -NC further confirmed that the catalyst is composed of Rh, C, N and O elements. Surface composition analysis using XPS revealed that the atomic ratio of _Rhx -C was similar to that of _Rhx -NC (Fig. 4b). Figure 4c depicts the Rh 3d spectrum of Rh _x -NC, which can be divided into two distinct peaks of metallic (307.57, 312.17 eV) and oxidized Rh (309.47, 314.17 eV) species. It is worth noting that the proportion of metallic rhodium (Rh ⁰ ) in Rh _x -C is higher than that of Rh _x -NC, which means that the introduction of N leads to a large amount of electron transfer from Rh to N, thereby reducing the electron density around Rh atoms. The high-resolution N 1s spectrum of Rh _x -NC (Fig. 4d) confirms the formation of Rh-N bonds, which can be seen from the peak corresponding to the binding energy of metal-N bonds at 397.38 eV. In addition, the peaks at 398.4, 399.82, and 401.08 are assigned to pyridyl N, pyrrolyl N, and graphityl N, respectively, indicating the doping of heteroatom N in carbon.

Experimental example 2 Electrocatalytic performance test of Rh _x -NC

Owing to the unique structure of Rh _x -NC, which consists of Rh nanoclusters and N-doped carbon, we evaluated its electrocatalytic performance for HER in argon-saturated 1.0 M KOH solution.

Preparation of Ink: Mix catalyst powder (10 mg) with 100 μL Nafion solution (5 wt %) and 900 μL ethanol to prepare catalyst ink in an ultrasonic bath; then transfer 5 μL of catalyst ink to the surface of GC to allow catalyst loading is 0.25 mg cm ^-2 .

Electrocatalytic testing: Electrochemical performance was performed by a Gamry reference 600 workstation (Gamry, USA) using a standard three-electrode system. The electrolyte was prepared by dissolving 33 g KOH (reagent grade, 85%, Aladdin Co.) in 500 mL ultrapure water. A reversible hydrogen electrode (RHE) was used as a reference electrode in a 1.0 M saturated KOH solution, and a graphite rod was used as a counter electrode. Using a glassy carbon rotating disk electrode (RDE) with an area of 0.196 cm ² as the substrate of the working electrode, the hydrogen evolution reaction activity of various catalysts was evaluated. The measured polarization curves were carried out in Ar-saturated 1.0 M KOH, 1.0 M PBS or 0.5 M H ₂ SO ₄ electrolytes, with a scan rate of 10 mV s ^-1 and a rotation speed of 1600 rpm, with real-time compensation and automatic correction. Under the condition of current density of 10 mA cm ^-2 , the stability test of the Rh _x -NC catalyst and the product obtained in the comparative example was carried out by chronopotentiometry.

The calculation formula of the mass activity is: mass activity = I/m, wherein I (A) is the measured current, and m (mg) is the mass of Rh loaded on the glassy carbon electrode.

The conversion frequency (TOF) is calculated as: TOF = I/2nF, where I (A) is the measured current. F is Faraday's constant (96485 mol ^-1 ). n = m/ m, n is the active number of Rh loaded on the glassy carbon electrode (mol), m is the mass of Rh, and M is the atomic mass.

For comparison, we also evaluated the HER performance of Rh _x -C, 20 wt% Pt/C, and 10 wt% Rh/C under the same conditions. As shown in the linear sweep voltammogram in Fig. 5a, the Rh _x -NC (Rh: 2.85 wt%) obtained in Example 1 exhibited significantly high HER activity compared with Rh/C and Pt/C. At a current density of 10 mA cm ^-2 , compared with Rh _x -C (98 mV), Rh/C (79 mV) and Pt/C (38 mV) (Fig. 5b), the Rh _x -NC obtained in Example 1 A much lower overpotential of 16 mV is required. The Tafel slope of Rh _x -NC is only 43 mV dec ^-1 , much lower than that of Pt/C (53 mV dec ^-1 ), Rh/C (149 mV dec ^-1 ) and Rh _x -C (100 mV dec -1 ^). The Tafel slope of ¹ ) also further confirms the excellent HER performance of the catalyst obtained in the present invention (Fig. 5c).

Considering the catalyst cost in practical applications, the mass activities of Rh _x -NC, Rh _x -C, and commercial Rh/C catalysts were evaluated by normalizing the LSV curves to the mass of Rh, respectively. As shown in Figure 5d, Rh _x -NCs exhibit excellent mass activity in 1.0 M KOH solution. At an overpotential of 100 mV, Rh _x -NC exhibited a high mass activity of 12.685 A mg ^-1 Rh, which was about 7.8 times higher than that of Rh _x -C (1.615 A mg ^-1 ) and higher than that of Rh/C (0.56 A mg -1 ). mg ^-1 ) was 22.6 times higher. Another critical factor in evaluating the intrinsic catalytic performance of electrocatalysts is the turnover frequency (TOF). At an overpotential of 100 mV, Rh _x -NC exhibited a remarkably high turnover frequency of 6.77 H ₂ s ^-1 , which is higher than that of Rh _x -C (0.86 H ₂ s ^-1 ), Rh/C (0.30 H ₂ s ^-1 ), even most of the reported HER electrocatalysts are high. This result further confirms that the Rh _x -NC catalyst obtained in the present invention has much higher active sites than Rh _x -C, that is, Rh _x -NC has a great advantage in HER electrocatalytic performance.

Electrochemical impedance measurement (EIS) was used to study the electron/proton transfer at the catalyst-electrolyte interface, which can also illustrate that Rh _x -NC has the fastest electron transfer during HER (Fig. 6a). Furthermore, we investigated the double-layer capacitance (C _dl ) of the catalyst, which is positively correlated with the electrochemically active surface area (ECSA). As shown in Fig. 6b, Rh _x -NCs have a higher _Cdl , indicating a larger ECSA for their electrocatalysis. This can be attributed to the hierarchically ordered porous structure, which highly exposes Rh nanoclusters and enhances the utilization of Rh active sites.

In order to _further evaluate the practical application value of the Rh _x -NC electrocatalyst, we conducted a chronovoltage test to evaluate its application stability ^. It has stable HER catalytic activity (Fig. 7).

To investigate the HER catalytic activity of Rh _x -NC at different pH, we further investigated its performance in 0.5M _H2SO4 solution and 1.0 M phosphate buffered saline ( _PBS ). As shown in Fig. 8a,c, Rh _x -NC exhibited overpotentials of 8 and 109 mV at 10 mA ^cm in 0.5 M H ₂ SO ₄ solution and 1.0 M PBS, respectively. Under alkaline and neutral conditions, Rh _x -NCs exhibit significantly higher current densities than Pt/C at different overpotentials. Furthermore, there is no significant difference in the current density between Rh _x -NC and Pt/C in acidic solution. Under acidic, neutral, and alkaline conditions, the Tafel slope of Rh _x -NC is lower than that of Rh/C and Pt/C (Fig. 8b,d). These results demonstrate that Rh _x -NC is an efficient electrocatalyst for HER. In addition, the pH value had little effect on the HER performance of Rh _x -NCs compared with Pt/C, suggesting that Rh _x -NCs can effectively overcome the hydrolysis energy barrier, which is crucial for catalyzing HER under non-acidic conditions. of. Furthermore, Rh _x -NCs exhibit excellent stability in both acidic and neutral solutions (Fig. 9a,b).

The LSV curves of the Rh cluster-loaded NC material (Rh _x /NC) obtained in Comparative Example 4 of the present invention in different electrolytes are shown in Figure 10. It can be seen from Figure 10 that Rh _x /NC is at 1.0 M KOH, 0.5 MH ₂ The overpotentials required to achieve a current density of 10 mA cm ^-2 in SO ₄ and 1.0 M PBS are 26, 86, and 273 mV, respectively, which are inferior to Rh _x -NC, which confirms that the Rh _x -NC obtained by the method of the present invention has The Rh-N coordination structure can significantly enhance the HER catalysis.

In addition, the present invention also studies the HER catalytic activity of the catalysts obtained in Examples 2-8. It can be seen from Figure 11 that the catalysts obtained in Examples 2-4 all have better catalytic activity for HER, and the overpotentials of Examples 2, 3, and 4 at 10 mA cm ^-2 are 111 mV, 66 mV, and 14 mV, respectively.

It can be seen from Figure 12 that electrocatalysts with better HER catalytic activity can be obtained in the temperature range of 500-800 °C, and the overpotentials of Examples 5-7 at 10 mA cm ^-2 are 91 mV, 78 mV and 61 mV.

The Ir _x -NC catalyst obtained in Example 8 needs an overpotential of 75 mV to obtain a current density of 10 mA cm ^-2 in a 1.0 M KOH electrolyte (as shown in Figure 13); it can be seen that the Ir _x -NC catalyst obtained in the present invention It also has good HER catalytic performance.

In summary, the present invention has developed a novel electrocatalyst prepared from Rh or Ir nanoclusters supported by N-doped carbon supports. Overpotentials as low as 8, 16, and 108 mV are required to achieve a current density of 10 mA cm ^-2 in , alkaline, and neutral electrolytes, respectively. The unique coordination chemical structure of Rh-N or Ir-N precisely tunes the geometric and electronic structures of Rh or Ir species. This rational regulation strategy of coordination chemistry can induce the transfer of electrons from the Rh site to the N site, thereby causing electron redistribution on the carbon support, optimizing the adsorption energy of reaction intermediates, and ultimately improving the electrocatalytic performance. Therefore, the discovery of Rh _x -NC or Ir _x -NC catalysts provides a unique idea for the rational design of efficient active sites, that is, tuning the adsorption of intermediates by manipulating the coordination chemistry.

Claims (9)

1. A method of preparing a HER electrocatalyst, comprising:

dispersing rhodium salt or iridium salt in an alcohol solvent to form a stable and transparent solution, adding a nitrogen-containing substance into the solution, and stirring to dissolve the nitrogen-containing substance;

adding the carbon substrate, and stirring and uniformly mixing;

then standing, aging and complexing the obtained reaction system to obtain gel-like solid;

and then placing the obtained gel-like solid in an inert gas environment, heating for 2-5 h at 65-75 ℃, then heating to 500-800 ℃ and keeping the temperature for 2-3 h, finally cooling to room temperature and standing for 1-2 h to obtain the HER electrocatalyst.

2. The method for preparing a HER electrocatalyst according to claim 1, wherein the nitrogen-containing substance is urea or melamine.

3. The method for preparing a HER electrocatalyst according to claim 1 or 2, wherein the carbon substrate is ketjen black, carbon nanotubes or graphene.

4. A method of preparing a HER electrocatalyst according to claim 1 or 2, wherein the rhodium salt is selected from: rhCl ₃ ·xH ₂ O、Rh(NO ₃ ) ₃ ·xH ₂ O、Rh ₂ (SO ₄ ) ₃ Or (NH) ₄ ) ₃ RhCl ₆ 。

5. According to claim 1 or 2A process for the preparation of HER electrocatalyst, characterized in that the iridium salt is selected from IrCl ₃ · xH ₂ O。

6. The preparation method of the HER electrocatalyst according to claim 1 or 2, wherein the mass ratio of rhodium salt or iridium salt to nitrogen-containing substance is 0.1-10: 200.

7. the preparation method of the HER electrocatalyst according to claim 1 or 2, wherein the mass ratio of the nitrogen-containing substance to the carbon substrate is 10 to 20:1.

8. a HER electrocatalyst, characterized in that it is produced by the production process according to any one of claims 1 to 7.

9. A HER electrocatalyst according to claim 8, wherein the electrocatalyst is a support in which Rh clusters or Ir clusters are uniformly supported on nitrogen-doped carbon, and wherein the electrocatalyst comprises Rh-N coordination or Ir-N coordination.