A confined noble metal titanium dioxide nanoarray electrocatalyst, its preparation method and application

Abstract

This invention discloses a titanium dioxide nanoarray electrocatalyst with confined noble metals, its preparation method, and its application. The catalyst comprises a titanium substrate, a titanium dioxide nanoarray, and rhodium nanoparticles. The titanium dioxide nanoarray is grown on the surface of the titanium substrate; the rhodium nanoparticles are confined at the interface between the titanium dioxide nanoarray and the titanium substrate. The reverse confinement structure in this titanium dioxide nanoarray electrocatalyst, where the Rh nanoparticles are completely confined at the root of the TiO2 nanoarray, solves the problems of noble metal corrosion, poisoning, and shedding in seawater electrolysis. It also simultaneously exhibits excellent catalytic activity and stability for the hydrogen evolution reaction, demonstrating significant application potential in seawater electrolysis for hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of new energy materials technology, specifically relating to a confined noble metal titanium dioxide nanoarray electrocatalyst, its preparation method and application. Background Technology

[0002] Hydrogen energy is considered one of the most promising clean energy sources for the future. Water electrolysis is a crucial method for achieving large-scale green hydrogen production. Seawater resources are abundant, and seawater electrolysis offers a promising future for sustainable hydrogen production. However, seawater contains high concentrations of Cl-. - Ca 2+ Mg 2+ Impurity ions, including Cl - It will have a strong corrosive and poisoning effect on the active components of precious metals, leading to a rapid decline in catalyst activity; Ca 2+ Mg 2+ Insoluble hydroxide precipitates will be generated during cathode electrolysis, covering the active sites and causing catalyst deactivation. From the perspective of large-scale hydrogen production by water splitting, electrocatalysts should have the following necessary properties: (1) High intrinsic catalytic activity to achieve a large hydrogen evolution reaction current density under low overpotential and seawater conditions. (2) Strong corrosion resistance and electrochemical / mechanical stability under high current density. The H2 bubbles generated during electrolysis will have a strong scouring effect on the surface-loaded active components, causing noble metal particles to fall off and aggravating catalyst deactivation. Therefore, designing and developing hydrogen production electrocatalysts that can operate efficiently and stably under harsh seawater conditions is extremely challenging.

[0003] Currently, to improve the stability of seawater electrolysis catalysts, research commonly employs strategies such as surface coating with anti-corrosion layers or loading noble metals onto supports with large specific surface areas. However, the noble metals exposed on the outermost layer are still directly exposed to the attack of corrosive ions in seawater, making them highly susceptible to detachment, poisoning, or obscuring by precipitates. Furthermore, the long electron transport path between the noble metal and the substrate (requiring passage through a semiconductor array) increases contact resistance, ultimately trapping the catalyst in a dilemma: "high activity necessitates exposed sites, but exposed sites inevitably lead to rapid deactivation." Therefore, developing a seawater electrolysis hydrogen electrode that simultaneously achieves high catalytic activity and ultra-long corrosion resistance while simplifying the preparation process is a pressing technical problem to be solved in this field. Summary of the Invention

[0004] To overcome the problems existing in the prior art, one objective of this invention is to provide a titanium dioxide nanoarray electrocatalyst. A second objective is to provide a method for preparing the aforementioned titanium dioxide nanoarray electrocatalyst. A third objective is to provide an electrode. A fourth objective is to provide applications of the aforementioned titanium dioxide nanoarray electrocatalyst and electrode.

[0005] This invention innovatively proposes confining rhodium nanoparticles within a three-dimensional titanium dioxide nanoarray and a titanium substrate. This avoids direct contact between impurity ions and the rhodium active sites in seawater hydrogen evolution reactions, achieving excellent catalytic stability. Furthermore, the hierarchical channels in the titanium dioxide nanoarray allow hydrogen bubbles generated during the hydrogen evolution reaction to escape rapidly, ensuring catalytic stability at high current densities. The titanium dioxide nanoarray electrocatalyst of this invention simultaneously exhibits excellent catalytic activity and stability for the hydrogen evolution reaction, demonstrating significant application potential in seawater electrolysis for hydrogen production.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a titanium dioxide nanoarray electrocatalyst, comprising a titanium substrate, a titanium dioxide nanoarray, and rhodium nanoparticles; the titanium dioxide nanoarray is grown on the surface of the titanium substrate; and the rhodium nanoparticles are confined at the interface between the titanium dioxide nanoarray and the titanium substrate.

[0007] Preferably, the titanium dioxide nanoarray is composed of titanium dioxide nanorods arranged in an interlaced (non-parallel or cross) manner to construct an array structure with hierarchical channels.

[0008] More preferably, the length of the titanium dioxide nanorods is 10-800 nm.

[0009] Preferably, the rhodium nanoparticles are attached to the surface of the titanium substrate.

[0010] More preferably, the rhodium nanoparticles have a particle size of 55-60 nm. Preferably, the titanium substrate is titanium foam or titanium sheet.

[0011] More preferably, the foamed titanium or titanium sheet is square or circular in shape. More preferably, the square has a length ≤ 400 mm and a width ≤ 400 mm. More preferably, the circular has a diameter ≤ 400 mm.

[0012] More preferably, the thickness of the titanium substrate is ≤5 mm.

[0013] A second aspect of the present invention provides a method for preparing the titanium dioxide nanoarray electrocatalyst described in the first aspect, comprising the following steps: A titanium substrate was placed in a mixed solution, a rhodium source was added and mixed, and a solvothermal reaction was carried out to prepare the titanium dioxide nanoarray electrocatalyst; the mixed solution included ethylene glycol, water and hydrochloric acid.

[0014] In the above solvothermal reaction process, the reduction potential of the Rh source is higher than that of the Ti source in terms of hydrolysis and oxidation. Therefore, the Rh source is preferentially reduced over the TiO2 precursor to generate Rh nanoparticles that are uniformly attached to the surface of the Ti substrate. As the reaction time increases, the Ti substrate undergoes hydrolysis and directional oxidation under the action of the mixed solvent and hydrochloric acid to generate TiO2 nanoarrays that grow perpendicular to the substrate and interleaved with each other. During the growth process, the Rh nanoparticles that are pre-attached to the substrate are pushed upwards, and finally the Rh nanoparticles are completely confined in situ at the root of the TiO2 nanoarray and the interface between the Ti substrate.

[0015] Preferably, in the mixed solution, the volume ratio of ethylene glycol to water is (1~4):1.

[0016] More preferably, in the mixed solution, the volume ratio of ethylene glycol to water is 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, or a range of any two of the above values.

[0017] Preferably, in the mixed solution, the volume ratio of hydrochloric acid to water is (0.1~0.5):1.

[0018] More preferably, in the mixed solution, the volume ratio of hydrochloric acid to water is 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, or a range of any two of the above values.

[0019] Preferably, the hydrochloric acid is concentrated hydrochloric acid with a concentration of 36% to 338%.

[0020] Preferably, the reaction temperature of the solvothermal reaction is 160~220℃.

[0021] More preferably, the reaction temperature of the solvothermal reaction is 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220°C or a range of any two of the above values.

[0022] Preferably, the reaction time of the solvothermal reaction is 16-20 h.

[0023] More preferably, the reaction time of the solvothermal reaction is 16, 17, 18, 19, 20 h or a range of any two of the above values.

[0024] More preferably, the heating program for the solvothermal reaction is as follows: heating rate of 2~5℃ / min, holding temperature of 160~200℃, and holding time of 16~20 h.

[0025] Preferably, the volume-to-mass ratio of the mixed solution to the rhodium source is (100-300) mL:1 mmol.

[0026] More preferably, the volume-to-mass ratio of the mixed solution to the rhodium source is 100 mL:1 mmol, 110 mL:1 mmol, 120 mL:1 mmol, 130 mL:1 mmol, 140 mL:1 mmol, 150 mL:1 mmol, 160 mL:1 mmol, 170 mL:1 mmol, 180 mL:1 mmol, 190 mL:1 mmol, 200 mL:1 mmol, 210 mL:1 mmol, 220 mL:1 mmol, 230 mL:1 mmol, 240 mL:1 mmol, 250 mL:1 mmol, 260 mL:1 mmol, 270 mL:1 mmol, 280 mL:1 mmol, 290 mL:1 mmol, 300 mL:1 mmol, or a range of any two of the above values.

[0027] Preferably, the rhodium source is a soluble rhodium salt.

[0028] More preferably, the rhodium source includes at least one of rhodium trichloride hydrate, rhodium nitrate, and rhodium sulfate.

[0029] Preferably, before the solvothermal reaction, a pretreatment is performed on the titanium substrate to remove the surface oxide layer.

[0030] More preferably, an acid pickling solution is used to remove the surface oxide layer of the titanium substrate; the acid pickling solution includes hydrofluoric acid, acid, and water.

[0031] A third aspect of the present invention provides an electrode comprising the titanium dioxide nanoarray electrocatalyst described in the first aspect.

[0032] The fourth aspect of the present invention provides the application of the titanium dioxide nanoarray electrocatalyst described in the first aspect, or the electrode described in the second aspect, in the catalysis of the hydrogen evolution reaction.

[0033] Preferably, the titanium dioxide nanoarray electrocatalyst described in the first aspect, or the electrode described in the second aspect, is used in the hydrogen evolution reaction in seawater.

[0034] More preferably, it is applied in seawater electrolysis hydrogen production, high-salinity wastewater hydrogen production, water electrolysis devices, and renewable energy coupled hydrogen production systems.

[0035] The beneficial effects of this invention are: This invention provides a titanium dioxide nanoarray electrocatalyst, wherein the titanium dioxide nanoarray is grown on the surface of a titanium substrate; rhodium nanoparticles are confined at the interface between the titanium dioxide nanoarray and the titanium substrate; a reverse confinement structure is constructed in which Rh nanoparticles are completely confined at the root of the TiO2 nanoarray, which is completely different from the design logic of traditional catalysts where "active sites must be exposed on the surface," thus solving the problems of corrosion, poisoning, and shedding of precious metals in seawater electrolysis. The titanium dioxide nanoarray electrocatalyst of this invention also has the following effects: ① Strong electron transport effect: Rh nanoparticles are directly attached to the highly conductive Ti substrate, and the electron transport path is almost zero, avoiding ohmic losses in long-distance transmission of semiconductor TiO2 arrays; ② Armor protection effect: The TiO2 nanoarray forms a dense physical barrier, which can block Cl in seawater. - Ca 2+ Mg 2+ Direct contact with Rh active sites avoids corrosion and poisoning, achieving an ultra-long catalytic stability of 700 hours; ③ Highly efficient mass transfer and bubble desorption effect: The coarse and fine uneven TiO2 array, regulated by an ethylene glycol-water mixed solvent, forms hierarchical channels, allowing H2 bubbles generated at the root to rapidly overflow along the channels without retention or blockage, ensuring catalytic stability at high current densities. The titanium dioxide nanoarray electrocatalyst of this invention simultaneously exhibits excellent catalytic activity and stability for the hydrogen evolution reaction, demonstrating significant application potential in seawater electrolysis for hydrogen production.

[0036] This invention provides a method for preparing the above-mentioned titanium dioxide nanoarray electrocatalyst. Specifically, a one-step preparation process can achieve in-situ growth of TiO2 array and root confinement of Rh nanoparticles. It has the advantages of being simple and controllable, suitable for large-scale production, requiring no subsequent secondary processing steps such as precious metal deposition or impregnation, having fewer process steps, mild reaction conditions, no need for complex equipment, good batch repeatability, and being suitable for large-scale industrial preparation. Attached Figure Description

[0037] Figure 1 TEM image and EDS elemental distribution map of the Rh / TiO2 electrode prepared in Example 1 of this invention; Figure 2 The XRD pattern of the Rh / TiO2 electrode prepared in Example 1 of this invention; Figure 3 These are SEM images showing the morphological evolution of samples at different reaction times according to the present invention. Figure 4 This is a scanning electron microscope image of the Rh / TiO2 sample from Example 1 of the present invention; Figure 5 This is a scanning electron microscope image of the Rh / TiO2-1:1 sample from Example 1; Figure 6The image shows a scanning electron microscope (SEM) image of the Rh / TiO2-EG-2step sample from Comparative Example 1. Figure 7 The image shows a scanning electron microscope (SEM) image of the Rh / TiO2-2:1-2step sample from Comparative Example 1. Figure 8 The graphs show the electrocatalytic hydrogen evolution polarization curves of Example 1 and Comparative Example 1 (Rh / TiO2-EG-2step). Figure 9 This is the long-term constant current stability test curve of Embodiment 1 of the present invention. Detailed Implementation

[0038] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels or prepared and isolated through simple synthesis; unless otherwise specified, the processes employed are conventional processes in the art.

[0039] Example 1 This embodiment provides a TiO2 nanoarray integrated electrode with root-confined Rh, which is prepared through the following steps: S1 Ti substrate pretreatment: Cut a 0.5mm thick Ti sheet into 2cm×3cm dimensions, and ultrasonically clean it for 15min each with acetone, anhydrous ethanol, and deionized water to remove surface oil. Then, etch it in an etching solution of hydrofluoric acid:nitric acid:deionized water = 1:4:5 for 30s to remove the surface oxide layer. After removal, rinse it repeatedly with deionized water 5 times, blow it dry with nitrogen, and set it aside. S2 One-step solvothermal reaction: The pretreated Ti sheet is tilted and placed into a 30mL polytetrafluoroethylene reactor liner. 10mL of ethylene glycol and 5mL of deionized water are added sequentially, and the mixture is stirred until homogeneous to obtain an ethylene glycol-water mixed solvent. Then, 1.4mL of concentrated hydrochloric acid (37% by mass) is added, and the mixture is stirred until homogeneous. Finally, 26.3mg of rhodium trichloride hydrate (RhCl3) is added. Add 3H2O and stir until completely dissolved; place the liner into a stainless steel reactor and seal it; place it in an oven and heat it to 200°C, keep it at that temperature for 18 hours, and then let it cool naturally to room temperature. S3 Post-processing: The reacted Ti sheet was removed and rinsed four times each with deionized water and anhydrous ethanol, then dried under nitrogen at room temperature to obtain the root-confined Rh TiO2 nanoarray integrated electrode, labeled Rh / TiO2. Characterization: In the Rh / TiO2 electrode prepared in this embodiment, Rh particles are completely confined at the junction of the TiO2 array root and the Ti substrate, with no exposed Rh particles on the array surface; the Rh mass loading is 13.56 μg / cm³. -2 This forms a hierarchical pore structure with varying diameters. Example 2: Different solvent ratios The only difference between this embodiment and Example 1 is that in step S2, the volume ratio of ethylene glycol to deionized water is 1:1. All other steps and parameters are the same as in Example 1, and the integrated electrode prepared is labeled as Rh / TiO2-1:1.

[0040] Example 3: Different solvent ratios The only difference between this embodiment and Example 1 is that in step S2, the volume ratio of ethylene glycol to deionized water is 1:2. All other steps and parameters are the same as in Example 1, and the integrated electrode prepared is labeled as Rh / TiO2-1:2.

[0041] Example 4 Different reaction times The only difference between this embodiment and Example 1 is that in step S2, the solvothermal reaction time is 3, 6, and 9 hours. All other steps and parameters are the same as in Example 1. The integrated electrodes prepared are labeled as Rh / TiO2-3h, Rh / TiO2-6h, and Rh / TiO2-9h, respectively.

[0042] Comparative Example 1 This embodiment provides a two-step method for synthesizing a TiO2 array-supported Rh particle catalyst. The distribution of Rh particles on the TiO2 array varies depending on the synthesis solvent. When the solvent is pure EG, Rh is uniformly distributed across the TiO2 array. When the solvent is a mixture of EG and water, Rh is concentrated at the top of the TiO2 array. The preparation method is as follows: A 2 cm × 3 cm layer of cleaned titanium foam, ethylene glycol / water mixtures of different volume ratios, and 1 ml of hydrochloric acid were placed in a 30 ml stainless steel reactor. The reactor was then transferred to an oven and heated at 200°C for 18 hours. After cooling, the resulting sample was removed from the reactor and thoroughly cleaned with ethanol to obtain a nanoarray of TiO2.

[0043] Different TiO2 / Ti nanoarrays with varying array structures were obtained by changing the ratio of EG and water. In this experiment, three groups of EG / water ratios were set: 15 ml EG / 0 ml water, 5 ml EG / 10 ml water, and 10 ml EG / 5 ml water. The prepared electrodes were labeled as Rh / TiO2-EG-2step, Rh / TiO2-1:2-2step, and Rh / TiO2-2:1-2step, respectively.

[0044] The obtained TiO2 nanoarray (2cm × 3cm) was placed obliquely in a flask, and 6.0 ml of EG containing 26.3 mg Cl3H6O3Rh and 120 mg was added. The flask was heated in an oil bath to 160 °C for 12 hours. After cooling, the collected Rh / TiO2 / Ti sheet-like product was washed with ethanol and dried in an oven at 60 °C for 10 hours.

[0045] Material physicochemical characterization Figure 1 These are TEM images and EDS elemental distribution maps of the Rh / TiO2 electrode prepared in Example 1. The microstructure of the Rh / TiO2 electrode was characterized using a combination of TEM and EDS elemental surface scanning. The TEM images show that Rh nanoclusters are attached to the substrate and encapsulated and confined beneath the TiO2 nanoarray. The EDS elemental surface scanning results show that the Ti and O elemental signals completely correspond to the morphology of the TiO2 nanoarray, while the Rh elemental signal is only distributed in the lower / inner region of the TiO2 array, forming a clear spatial confinement relationship with the TiO2 array, with no Rh signal diffusing to the outside of the array. This result demonstrates that the structure of Rh being successfully anchored and confined by the TiO2 nanoarray effectively suppresses the migration and aggregation of Rh nanoparticles.

[0046] Figure 2 The XRD pattern of the Rh / TiO2 electrode prepared in Example 1 of this invention is shown. XRD was used to characterize the phase composition of the Rh / TiO2 catalyst. The results show that the diffraction peaks of the Rh / TiO2 sample mainly correspond to rutile TiO2 (PDF#04-005-6161), while retaining the characteristic peaks of the Ti substrate, proving that TiO2 was successfully grown on the Ti sheet. No obvious characteristic diffraction peaks of metallic Rh (PDF#97-067-1063) were observed in the sample, indicating that Rh was confined below the TiO2 array, and there were almost no Rh particles on the sample surface. This result is consistent with the microstructure characterization by SEM, TEM, and EDS.

[0047] Figure 3 SEM images showing the morphological evolution of samples at different reaction times in this invention were used to characterize the morphology at different reaction times, and the dynamic evolution behavior of Rh particles during the growth of TiO2 nanoarrays was systematically studied. The results show that: In the initial stage of the reaction (3h): Rh nanoparticles are uniformly attached to the surface of the Ti substrate, while TiO2 is only in the nucleation stage and has no significant effect on Rh. Mid-reaction period (6h): TiO2 nanowires grow rapidly, forming an interlaced array. The longitudinal growth force pushes some Rh particles out of the Ti sheet, while confining a large number of Rh particles below the array. In the middle and late stages of the reaction (9h-12h): the TiO2 array gradually becomes denser and matures, and the Rh particles are completely confined between the array and the substrate, forming a stable "Rh / TiO2" confined structure.

[0048] Figure 4 The image shows a scanning electron microscope (SEM) image of the Rh / TiO2 sample from Example 1 of this invention. It can be seen that the TiO2 nanoarrays are densely distributed and the surface of each nanorod is smooth, with no visible Rh particles attached to the nanorods.

[0049] Figure 5 The image shows a scanning electron microscope (SEM) image of the Rh / TiO2-1:1 sample from Example 1. It can be seen that Rh particles are attached to the surface of the nanoarray, and the growth of the nanoarray is relatively regular compared to the Rh / TiO2 sample, but it does not achieve the ideal staggered array morphology.

[0050] Figure 6 and Figure 7 The images show scanning electron microscope (SEM) images of the Rh / TiO2-EG-2step and Rh / TiO2-2:1-2step samples from Comparative Example 1. Rh particles are clearly visible covering the TiO2 array. In the Rh / TiO2-EG-2step sample, Rh nanoparticles are uniformly distributed across the entire surface of the TiO2 nanoarray rods. In the Rh / TiO2-2:1-2step sample, Rh nanoparticles are mainly concentrated at the top of the TiO2 nanoarray.

[0051] Characterization of catalytic performance of materials The test method includes the following steps: (1) Preparation of working electrode: The sample is clamped in a platinum-carbon electrode clamp, 1 cm·1 cm is immersed in the electrolyte, and then electrocatalytic test is performed. (2) Test conditions: The three-electrode test method is adopted, with the platinum-carbon electrode clamp containing the catalyst Rh / TiO2 as the working electrode, the reference electrode as mercury / mercuric oxide, the counter electrode as a carbon rod, the electrolyte as a 1.0 mol / L KOH seawater solution, and the linear sweep voltammetry (LSV) method is used for the test.

[0052] Figure 8 The electrocatalytic hydrogen evolution polarization curves of Rh / TiO2-EG-2step in Example 1 and Comparative Example 1 of this invention are shown. The HER performance of different Rh-based TiO2 catalysts was evaluated using linear sweep voltammetry (LSV). The results show that the Rh / TiO2 sample prepared by the Rh pre-supported + TiO2 array in-situ growth process exhibits the best HER activity: at 10 mA... cm -2At the specified current density, the overpotential of Rh / TiO2 is significantly lower than that of conventional loaded Rh / TiO2-1:1, Rh / TiO2-1:2, and the two-step Rh / TiO2-EG-2step; at a potential of -0.2V vs. RHE, the current density of Rh / TiO2 reaches -160 mA. cm -2 The efficiency was 1.5 times that of the conventionally loaded sample and 2.7 times that of the two-step sample. This result indicates that the confined structure of Rh pre-loading + in-situ growth of TiO2 array significantly optimizes the intrinsic catalytic activity of HER.

[0053] Figure 9 The long-term electrochemical stability of the Rh / TiO2 electrode was evaluated using the chronopotential method (CP) to obtain the long-term constant current stability test curves for Example 1. As shown in the figure, at 1A... cm -2 Under industrial-grade high current densities, the Rh / TiO2 electrode can operate stably for over 700 hours with no significant potential decay, exhibiting only minor normal fluctuations. These results demonstrate that the Rh / TiO2 electrode possesses excellent high-current stability and structural durability, meeting the application requirements for industrial seawater electrolysis to produce hydrogen.

[0054] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A titanium dioxide nanoarray electrocatalyst, characterized in that, It includes a titanium substrate, a titanium dioxide nanoarray, and rhodium nanoparticles; the titanium dioxide nanoarray is grown on the surface of the titanium substrate; the rhodium nanoparticles are confined at the interface between the titanium dioxide nanoarray and the titanium substrate.

2. The titanium dioxide nanoarray electrocatalyst according to claim 1, characterized in that, The titanium substrate is titanium foam or titanium sheet.

3. The method for preparing the titanium dioxide nanoarray electrocatalyst according to claim 1 or 2, characterized in that, Includes the following steps: A titanium substrate was placed in a mixed solution, a rhodium source was added and mixed, and a solvothermal reaction was carried out to prepare the titanium dioxide nanoarray electrocatalyst; the mixed solution included ethylene glycol, water and hydrochloric acid.

4. The method for preparing the titanium dioxide nanoarray electrocatalyst according to claim 3, characterized in that, In the mixed solution, the volume ratio of ethylene glycol to water is (1~4):1; And / or, in the mixed solution, the volume ratio of hydrochloric acid to water is (0.1~0.5):

1.

5. The method for preparing the titanium dioxide nanoarray electrocatalyst according to claim 3, characterized in that, The reaction temperature of the solvothermal reaction is 160~220℃.

6. The method for preparing the titanium dioxide nanoarray electrocatalyst according to claim 3, characterized in that, The reaction time for the solvothermal reaction is 16-20 h.

7. The method for preparing the titanium dioxide nanoarray electrocatalyst according to claim 3, characterized in that, The volume-to-mass ratio of the mixed solution to the rhodium source is (100-300) mL:1 mmol; And / or, the rhodium source is a soluble rhodium salt.

8. The method for preparing the titanium dioxide nanoarray electrocatalyst according to claim 3, characterized in that, Prior to the solvothermal reaction, a pretreatment is performed on the titanium substrate to remove the surface oxide layer.

9. An electrode, characterized in that, Includes the titanium dioxide nanoarray electrocatalyst as described in claim 1 or 2.

10. The application of the titanium dioxide nanoarray electrocatalyst according to claim 1 or 2, or the electrode according to claim 9, in the catalysis of the hydrogen evolution reaction.

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