Ir-doped WO3@TiN, and a preparation method and application thereof

Abstract

The application discloses an Ir-doped WO3@TiN and a preparation method and application thereof, designs a composite carrier of WO3 and TiN, and effectively improves the catalytic effect of noble metal Ir. WO3 and TiN are combined as a carrier through a hydrothermal reaction, in the process, free Ti in the solution is doped into the position of W atoms, the number of oxygen vacancies in WO3 is increased, the electronic configuration of Ir is optimized, and the OER reaction is facilitated; in addition, a large number of pores are generated when the hexagonal rod structure WO3 is combined with the particle structure TiN, the diffusion of water and oxygen in the PEMWE process is promoted, compared with other single materials as a carrier, the Ir / WO3@TiN has more comprehensive advantages and higher structural dimension, and the activity and stability of the reaction are increased. The three-electrode test result shows that the Ir / WO3@TiN only needs an overpotential of 253 mV to reach 10 mA cm ‑2 , and the Tafel slope is only 47.35 mV dec ‑1 . The mass activity (MA) can reach 920.93 mA mgIr ‑1 at 1.53 V vs RHE.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to an Ir-doped WO3@TiN, its preparation method, and its application. Background Technology

[0002] With global warming and energy shortages, the effective utilization of renewable energy has become a topic of great concern, prompting numerous scientific studies. Hydrogen energy, due to its high energy density and environmental friendliness, is considered one of the most promising energy sources. There are many methods for hydrogen production, among which proton exchange membrane electrolysis (PEMWE) is a highly regarded method due to its high power density, rapid start-up and shutdown response, high hydrogen purity, and low operating costs, enabling the sustainable use of intermittent energy. Industrially, the oxygen evolution reaction (OER) catalyst at the anode in PEMWE is primarily composed of the precious metal iridium (Ir). However, global annual Ir production is only 8 metric tons, and commercially available Ir loading is 2-4 mg / cm³. -2 Therefore, the load of Ir must be reduced by at least an order of magnitude for PEMWE to be used on a large scale.

[0003] In recent years, it has been discovered that the interaction between metals and supports can effectively prevent the aggregation of metal nanoparticles, increase the electrochemically active surface area, and improve the effective utilization rate of noble metals. Furthermore, it can promote electron transfer between charge carriers and metal sites, effectively enhancing electrochemical activity and device stability while reducing Ir loading. Oxygen-rich tungsten oxide (WO3) facilitates the adsorption and activation of water molecules, thereby accelerating the oxidation reaction of water. In addition, numerous studies using WO3 as a support have demonstrated strong metal-support interactions.

[0004] However, the low electrical conductivity of tungsten oxide limits its widespread application in PEMWE. Furthermore, the low porosity of the material restricts water vapor transport during the PEMWE process, increases mass transport impedance, and thus reduces the Faraday efficiency of the catalyst. Summary of the Invention

[0005] This invention provides an Ir-doped WO3@TiN, its preparation method, and its application. The WO3@TiN, as a catalyst support, can effectively improve the catalyst's performance. By incorporating Ti into the W atoms, the number of oxygen vacancies in WO3 is increased, optimizing the electronic configuration of Ir and facilitating the OER reaction. Furthermore, the combination of the hexagonal rod-shaped WO3 and the particulate TiN generates numerous pores, promoting the diffusion of water and oxygen during the PEMWE process. Compared to other single-material supports, it offers more comprehensive advantages and higher structural dimensionality, increasing the reaction's activity and stability. Three-electrode testing results show that Ir / WO3@TiN only requires an overpotential of 253 mV to reach 10 mA cm⁻¹. -2 The Tafel slope is only 47.35mV dec -1 Mass activity (MA) reached 920.93 mA mgIr at 1.53 V vs RHE. -1 This is higher than most reported noble metal catalysts. When used in PEMWE, the Ir loading in the anode catalyst layer is 0.3 mg cm⁻¹. -2 The current density reaches 1 Acm -2 The voltage was only 1.6 V, and at 1 A cm -2 It has been running stably for more than 200 hours.

[0006] One of the technical solutions of the present invention is to provide an Ir-doped WO3@TiN, wherein the WO3@TiN is composed of rod-shaped WO3 and granular TiN loaded on WO3; wherein Ir is loaded on WO3@TiN; wherein Ir and Ti replace the positions of W atoms.

[0007] The numerous pores created when the hexagonal rod-shaped WO3 combines with the granular TiN can promote the diffusion of water and oxygen during the PEMWE process. Compared with other single materials as supports, it has more comprehensive advantages and higher structural dimensionality, which increases the activity and stability of the reaction.

[0008] Furthermore, the Ir is one or more of metallic Ir and iridium oxide.

[0009] In the catalytic material Ir / WO3@TiN, the doping of diatomic atoms (Ti, Ir) can promote the generation of oxygen vacancies in WO3, regulate the electronic structure of Ir active sites, and reduce the formation of OOH* active intermediates, thereby improving the activity and stability of OER. Furthermore, WO3@TiN has high porosity, which is beneficial to the activity and long-term stability of PEMWE.

[0010] The second technical solution of the present invention provides a method for preparing the above-mentioned Ir-doped WO3@TiN, comprising the following steps:

[0011] (1) Synthesis of WO3@TiN with oxygen vacancies. Free Ti atoms at the interface will be doped into the tungsten lattice of tungsten oxide, thereby reducing the formation energy of oxygen vacancies and promoting the increase of oxygen vacancies. The oxygen vacancies will transfer excess electrons to the surrounding W atoms.

[0012] (2) Loading Ir onto WO3@TiN; wherein the Ir is one or more of metallic Ir and iridium oxide. Ir doping at the interface into the W lattice on the WO3 surface will produce the same effect as Ti doping, with the increased oxygen vacancies transferring excess electrons to Ir. In addition, WO3, as an electron transport intermediate, can also transport electrons from titanium nitride to Ir nanoparticles. Electron-rich Ir active sites can promote the OER reaction and prevent the loss of species in high valence states due to electron loss, thereby reducing stability. Furthermore, the composite structure of rods and particles generates a large number of pores, reducing the mass transport impedance of PEMWE and increasing the activity and stability of the reaction.

[0013] Furthermore, the WO3@TiN with oxygen vacancies is prepared via the following steps:

[0014] (1) Prepare a 15 mg / ml aqueous dispersion of TiN nanoparticles and stir for 30 min to obtain liquid 1;

[0015] (2) Ammonium tungstate tetrahydrate (ATT) and sodium dodecyl sulfate (SDS) in a mass ratio of (1.0-1.2):(0.4-0.6) are mixed and stirred in water for 3 h to form liquid 2. The concentration of SDS is 0.01-0.02 g / ml.

[0016] (3) Mix liquid 1 and liquid 2 and stir for 30-60 min, then sonicate until completely dispersed to obtain liquid 3; the volume ratio of liquid 1 to liquid 2 is (10-15):(30-50).

[0017] (4) Transfer liquid 3 to a reaction vessel and heat at 200°C for 4-8 hours;

[0018] (5) Cooling, washing with deionized water, and drying in air at 60°C for 8-12 hours to finally obtain the composite carrier WO3@TiN.

[0019] Furthermore, the method for loading Ir onto WO3@TiN is as follows:

[0020] Add 80-100 mg of WO3@TiN and 10-30 mg of hexadecyltrimethylammonium bromide (CTAB) to 50-100 ml of ethylene glycol (EG) and stir for 1-2 h. Then add chloroiridium(IV) hydrate containing not less than 50 mg of Ir to the resulting suspension and stir continuously for 1-3 hours. Reflux at 160-170 °C for 3-4 h. Finally, centrifuge the suspension, wash the solid with deionized water and ethanol, and then dry it overnight at 60-80 °C to obtain Ir / WO3@TiN.

[0021] The third technical solution of the present invention is to provide the application of the above-mentioned Ir-doped WO3@TiN in proton exchange membrane water electrolysis.

[0022] The beneficial effects of this invention are as follows: the composite material WO3@TiN as a support improves the activity and stability of the Ir catalyst in OER, while achieving excellent proton exchange membrane water electrolysis activity and stability. The mass activity (MA) can reach 920.93 mA mgIr at 1.53 V vs RHE. -1 . Attached Figure Description

[0023] Figure 1 The images show scanning electron microscope (SEM) and transmission electron microscope (TEM) images of WO3@TiN.

[0024] Figure 2 is Comparison of nitrogen adsorption-desorption (BET) curves for TiN and WO3@TiN.

[0025] Figure 3 A comparison of the electrical conductivity of TiN, WO3, and WO3@TiN.

[0026] Figure 4 This is a high-angle annular dark-field scanning transmission electron microscope (HADDF-STEM) image of Example 1 and an analysis of the elemental content corresponding to the selected area.

[0027] Figure 5 This is a comparison of electron paramagnetic resonance (EPR) spectra.

[0028] Figure 6 The graphs show a comparison of polarization curves (LSV) and Tafel slopes between Example 1 and commercial iridium oxide.

[0029] Figure 7 This is a comparison graph of the half-cell stability of Example 1 and commercial iridium oxide.

[0030] Figure 8 This is a comparison graph of the PEMWE activity of Example 1 and commercial iridium oxide.

[0031] Figure 9 This is a comparison chart of PEMWE stability between Example 1 and commercial iridium oxide. Detailed Implementation

[0032] The following examples are provided to further illustrate the present invention and are intended to explain the invention, not to limit its scope. Unless otherwise specified, all figures are expressed in parts by weight and weight percentages.

[0033] Unless otherwise specified, the raw materials used in this invention are all conventional commercially available products; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0034] The embodiments of the present invention will be further described below with reference to several examples.

[0035] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0036] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0037] Example 1

[0038] (1) Add 180 mg of TiN nanoparticles to 12 ml of H2O and stir for 30 min to make liquid 1.

[0039] (2) Ammonium tungstate tetrahydrate (ATT) and sodium dodecyl sulfate (SDS) in a mass ratio of 1.0:0.4 were mixed and stirred in water for 3 h to form liquid 2, with a concentration of 0.01 g / ml of SDS.

[0040] (3) Mix liquid 1 and liquid 2 for 30 min and sonicate until completely dispersed to obtain liquid 3; the volume ratio of liquid 1 to liquid 2 is 10:30.

[0041] (4) Transfer liquid 3 to the reactor and heat at 200°C for 4 hours.

[0042] (5) Cooling, washing with deionized water 3 times, and drying in air at 60°C for 8 hours to finally obtain the composite carrier WO3@TiN.

[0043] Depend on Figure 2 and Figure 3It can be seen that the nitrogen adsorption and desorption capacity of WO3@TiN is significantly better than that of TiN material without composite, and the electrical conductivity is significantly improved compared with pure WO3.

[0044] (6) Add 80 mg of WO3@TiN and 10 mg of hexadecyltrimethylammonium bromide (CTAB) to 50 ml of ethylene glycol (EG) and stir for 1 h; then add 50 mg of chloroiridium(IV) hydrate containing Ir to the resulting suspension, stir continuously for 1 h, and reflux at 160 °C for 3 h; finally, centrifuge the suspension, wash the solid with deionized water and ethanol, and then dry at 60 °C overnight to obtain Ir / WO3@TiN.

[0045] The resulting products are as follows Figure 1 (a) Scanning electron microscope (SEM) image shows granular TiN loaded on rod-shaped WO3, as seen by transmission electron microscopy (TEM). Figure 1 (b) We analyzed and obtained the crystal planes and their corresponding interplanar spacings of WO3 and TiN materials. In addition, the BET specific surface area test results ( Figure 2) The results show that the specific surface area of ​​WO3@TiN is higher than that of WO3, and the presence of hysteresis loops confirms the porous structure of the WO3@TiN composite material, which is consistent with the SEM results. The presence of TiN significantly improves the overall electrical conductivity of the composite material. Figure 3 In addition, scanning transmission electron microscopy (STEM) Figure 4 Linear scanning of its elemental content confirmed the incorporation of Ti and Ir elements in WO3, which is also the main reason for the increase in oxygen vacancies in Ir / WO3@TiN materials. Figure 5 ).

[0046] The performance of the catalyst was investigated in a standard three-electrode system using a CORRTEST instrument (CS2350). The electrolyte solution was 0.5 M H₂SO₄, and the counter and reference electrodes were a platinum foil and a saturated calomel electrode (SCE), respectively. All potentials were converted to potentials E relative to the reversible hydrogen electrode (RHE). RHE (Formula 1):

[0047] (1)

[0048] Where Esce is the voltage value obtained from the test, and 0.260 V is the potential value at zero current after we calibrated the SCE electrode with a standard hydrogen electrode before the test.

[0049] The catalyst ink was prepared by ultrasonically dispersing 3.27 mg of catalyst (IrO2) in a mixture of 10 µL Nafion solution (5 wt%) and 490 µL ethanol. Linear sweep voltammetry (LSV) was performed using a 5 mV / s² solution.-1 The sweep rate and 85% iR drop compensation. The Tafel slope is calculated based on η= blog j +α is applied, where b is the Tafel slope.

[0050] At 10 mA cm -2 Stability was assessed using a time-potential method, with no iR drop compensation. The working electrode was prepared by loading the catalyst onto hydrophilic carbon paper. The effective area of ​​the carbon paper was 1.0 cm². 2 The Ir loading was 0.01 mg / cm³. -2 The catalyst ink was repeatedly dropped onto the carbon paper surface and dried overnight in an oven at 60°C. In PEMWE, the cathode catalyst used was a commercial Pt / C (40 wt%, with a loading of 0.8 mg cm⁻¹). -2 The anode catalyst used was either the one described in this embodiment or a commercially available iridium oxide. First, a catalyst slurry was prepared by adding 100 mg of catalyst to 2 mL of H₂O and 10 mL of isopropanol (IPA) solution containing 200 mg Nafion (20 wt%), and then ultrasonically dispersing for 1 h. Subsequent electrode fabrication was performed by pneumatic spraying, with a Pt / C mass loading (40%) of 0.8 mg cm⁻¹ at the cathode. -2 The mass loadings of C-IrO2 on the anode were 0.3 and 1 mg cm⁻¹, respectively. -2 The mass loading of 30% Ir / WO3@TiN on the anode is 1 mg cm⁻¹. -2 That is, the mass loading of Ir is 0.3 mg cm⁻¹. -2 The anode catalyst is coated onto the membrane (Nafion 115), the gas diffusion layer is a Ti felt, and the cathode catalyst is coated onto the gas diffusion layer (Ti felt). Finally, the cathode gas diffusion layer, Nafion 115 membrane, and anode gas diffusion layer are combined and hot-pressed (130℃, 5 MPa, 5 min) to obtain the membrane electrode assembly (MEA) with an effective area of ​​5 cm². 2 The PEMWE test was conducted at 80 °C, with circulating deionized water passing through the anode at a temperature of 80 °C and a flow rate of 3 mL / min. -1 The LSV test voltage range is 1.4 V to 2.5 V, and the collected current utilizes the effective area of ​​the MEA (5 cm²). 2 The current density was obtained by normalization. Time potential (CP) was measured at a current density of 1.0 A cm⁻¹. -2 The process takes place over a period of 200 hours.

[0051] Its half-cell activity is as follows Figure 6As shown, when the Ir loading is 30 wt%, the catalyst Ir / WO3@TiN exhibits higher activity, with a current density of 10 mA cm⁻¹. -2 The overpotential was only 253 mV. The Tafel slope was also lower than that of commercial IrO2 (C-IrO2), at 47.35 mV dec. -1 At the same time, this catalyst also has higher stability ( Figure 7 Compared to C-IrO2, it can operate stably for more than 100 hours and has lower voltage decay.

[0052] Full cell activity test results are as follows Figure 8 As shown, the Ir loading was 0.3 mg / cm³. -2 30% Ir / WO3@TiN catalyst with different Ir loadings (0.3 mg cm⁻¹) -2 and 1.0 mg cm -2 A comparison of the polarization curves of C-IrO2 shows that 30% Ir / WO3@TiN exhibits significantly better catalytic activity than C-IrO2, achieving a current density of 1.0 A cm⁻¹ at 1.6 V. -2 , and 0.3 mg cm -2 C-IrO2 at a current density of 1.0 A cm⁻¹ -2 When the voltage is higher than 1.9 V, even commercially used MEAs (1.0 mg) are affected. Ir cm -2 It also requires a voltage of 1.8 V. Considering that the stability of the MEA is the most important criterion for practical applications, we set it at 1.0 A cm⁻¹. −2 The stability of 30% Ir / WO3@TiN was evaluated at a constant current density and temperature of 80 °C. Figure 9 As shown, the stable operating time of 30wt% Ir / WO3@TiN is over 200 hours, and the voltage drop (0.1 mV / h) is minimal. -1 It is smaller than C-IrO2. This demonstrates encouraging PEMWE application value.

[0053] Example 2

[0054] (1) Prepare a 15 mg / ml aqueous dispersion of TiN nanoparticles and stir for 30 min to obtain liquid 1.

[0055] (2) Ammonium tungstate tetrahydrate (ATT) and sodium dodecyl sulfate (SDS) in a mass ratio of 1.2:0.6 were mixed and stirred in water for 3 h to form liquid 2. The concentration of SDS was 0.02 g / ml.

[0056] (3) Mix liquid 1 and liquid 2 for 60 min and sonicate until completely dispersed to obtain liquid 3; the volume ratio of liquid 1 to liquid 2 is 15:50.

[0057] (4) Transfer liquid 3 to the reactor and heat at 200°C for 8 hours.

[0058] (5) Cooling, washing with deionized water, and drying in air at 60°C for 12 hours to finally obtain the composite carrier WO3@TiN.

[0059] (6) Add 100 mg of WO3@TiN and 30 mg of hexadecyltrimethylammonium bromide (CTAB) to 100 ml of ethylene glycol (EG) and stir for 2 h. Then add 200 mg of chloroiridium(IV) hydrate containing Ir to the resulting suspension, stir continuously for 3 h, and reflux at 170 °C for 4 h. Finally, centrifuge the suspension, wash the solid with deionized water and ethanol, and then dry at 80 °C overnight to obtain Ir / WO3@TiN.

[0060] Performance comparisons were performed using the testing method described in Example 1.

[0061] Comparative Example 1

[0062] (1) ATT (1.1 g) and SDS (0.5 g) were mixed with 50 ml H2O and stirred for 3 h. Then the mixture was transferred to a 100 ml reactor and heated to 200 °C for 6 h. After natural cooling, the mixture was washed several times with deionized water and dried in air at 60 °C for 12 h to obtain the support WO3.

[0063] (2) Add 80 mg of the supporting material WO3 and 10 mg of CTAB to 35 ml of EG and let it react for 1 h; then add 30 wt% chloroiridium(IV) hydrate of Ir to the resulting suspension, stir continuously for 2 h, and reflux at 165 °C for 3.5 h. Finally, centrifuge the suspension, wash with deionized water and ethanol, and then dry the Ir / WO3 at 60 °C.

[0064] Performance comparisons were performed using the testing method described in Example 1.

[0065] Comparative Example 2

[0066] 80 mg of TiN and 10 mg of CTAB were added to 35 ml of EG and allowed to react for 1 h. Then, 30 wt% iridium chloride (IV) hydrate of Ir was added to the resulting suspension, and the mixture was stirred continuously for 2 h and refluxed at 165 °C for 3.5 h. Finally, the suspension was centrifuged, washed with deionized water and ethanol, and then the Ir / TiN was dried at 60 °C.

[0067] Performance comparisons were performed using the testing method described in Example 1.

[0068] Table 1 Performance comparison of Examples 1 & 2 and Comparative Examples 1 & 2

[0069] Half-cell stability PEMWE activity PEMWE stability Example 1 <![CDATA[100 h@20 mA cm -2 ]]> <![CDATA[1.6 V@1 A cm -2 ]]> <![CDATA[200 h@1 A cm -2 ]]> Example 2 <![CDATA[60 h@20 mA cm -2 ]]> <![CDATA[1.81 V@1 A cm -2 ]]> <![CDATA[80 h@1 A cm -2 ]]> Comparative Example 1 <![CDATA[20 h@20 mA cm -2 ]]> <![CDATA[1.88 V@1 A cm -2 ]]> <![CDATA[30 h@1 A cm -2 ]]> Comparative Example 2 <![CDATA[40 h@20 mA cm -2 ]]> <![CDATA[1.94 V@1 A cm -2 ]]> <![CDATA[50 h@1 A cm -2 ]]>

[0070] As shown in Table 1, the oxygen evolution catalytic activity and stability of the Ir / WO3@TiN catalysts obtained in Examples 1 and 2 are significantly higher than those in Comparative Examples 1 and 2. In particular, the Ir / WO3@TiN catalyst prepared in Example 1 only requires 1.6 V to achieve 1 A cm⁻¹ in the PEMWE full-cell test. -2 It achieves the optimal current density and operates stably at that current density for over 200 hours, demonstrating the best oxygen evolution catalytic performance.

[0071] The above embodiments describe in detail the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall still fall within the scope of protection of the present invention if they do not exceed the scope covered by the specification.

Claims

1. An Ir-doped WO3@TiN, characterized in that, The WO3@TiN is composed of rod-like WO3 and granular TiN loaded on the WO3; wherein Ir and Ti replace the position of W atoms; the preparation method of the Ir-doped WO3@TiN has the following steps: (1) synthesizing WO3@TiN with oxygen vacancies; the WO3@TiN with oxygen vacancies is prepared by the following steps: 1) TiN nanoparticles are prepared into a water dispersion solution with a concentration of 15 mg / ml, and stirred for 30 min as liquid 1; 2) ammonium tungstate ATT and sodium dodecyl sulfate SDS with a mass ratio of (1.0-1.2):(0.4-0.6) are mixed in water and stirred for 3 h as liquid 2, and the concentration of SDS is 0.01-0.02 g / ml; 3) liquid 1 and liquid 2 are mixed and stirred for 30-60 min, and ultrasonic is applied until complete dispersion to obtain liquid 3; the volume ratio of liquid 1 to liquid 2 is 10-15:30-50; 4) liquid 3 is transferred into a reaction kettle, and heated at 200 ℃ for 4-8 hours; 5) after cooling, washing with deionized water, and drying in air at 60 ℃ for 8-12 hours, the composite carrier WO3@TiN is finally obtained; (2) loading Ir on WO3@TiN; the method for loading Ir on WO3@TiN is as follows: 80-100 mg of WO3@TiN and 10-30 mg of hexadecyl trimethyl ammonium bromide are added into 50-100 ml of ethylene glycol, and stirred for 1-2 h; then, hydrous chloroiridic acid containing not less than 50 mg of Ir is added into the obtained suspension, the valence of the iridium is tetravalent, and continuous stirring is applied for 1-3 hours, and refluxing is applied at 160-170 ℃ for 3-4 h; finally, the suspension is centrifuged, the solid is washed with deionized water and ethanol, and then dried at 60-80 ℃ overnight to obtain Ir / WO3@TiN.

2. The Ir-doped WO3@TiN of claim 1, wherein, The Ir is one or more of metallic Ir and iridium oxide.

3. A method of preparing Ir-doped WO3@TiN as claimed in claim 1, characterized by, has the following steps: (1) synthesizing WO3@TiN with oxygen vacancies; The WO3@TiN with oxygen vacancies is prepared by the following steps: 1) TiN nanoparticles are prepared into a water dispersion solution with a concentration of 15 mg / ml, and stirred for 30 min as liquid 1; 2) ammonium tungstate ATT and sodium dodecyl sulfate SDS with a mass ratio of (1.0-1.2):(0.4-0.6) are mixed in water and stirred for 3 h as liquid 2, and the concentration of SDS is 0.01-0.02 g / ml; 3) liquid 1 and liquid 2 are mixed and stirred for 30-60 min, and ultrasonic is applied until complete dispersion to obtain liquid 3; the volume ratio of liquid 1 to liquid 2 is 10-15:30-50; 4) liquid 3 is transferred into a reaction kettle, and heated at 200 ℃ for 4-8 hours; 5) after cooling, washing with deionized water, and drying in air at 60 ℃ for 8-12 hours, the composite carrier WO3@TiN is finally obtained; (2) loading Ir on WO3@TiN; the Ir is one or more of metallic Ir and iridium oxide; The method of loading Ir on WO3@TiN is as follows: 80-100 mg of WO3@TiN and 10-30 mg of cetyltrimethylammonium bromide are added in 50-100 ml of ethylene glycol, stirred for 1-2 h; then 50 mg or more of iridium chloride hydrate containing not less than 50 mg of Ir, the valence of which is tetravalent, is added to the obtained suspension, continuously stirred for 1-3 h, refluxed at 160-170°C for 3-4 h; finally the suspension is centrifuged, the solid is washed with deionized water and ethanol, and then dried at 60-80°C overnight to obtain Ir / WO3@TiN.

4. Use of the Ir-doped WO3@TiN according to claim 1 in proton exchange membrane water electrolysis.

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