Nano etched silver electrode loaded with transition metal catalyst and preparation method and application of nano etched silver electrode

Abstract

The invention discloses a nano etched silver electrode loaded with a transition metal catalyst and a preparation method and application thereof, and belongs to the technical field of electro-catalytic materials, the preparation method comprises the following steps: (1) cleaning a silver substrate, and carrying out etching treatment on the cleaned silver substrate by using HNO3 to obtain an etched silver electrode; (2) dropwise adding an alkali solution into a mixed solution of soluble cobalt salt and soluble iron salt, adjusting the pH value of the solution to 10-11 after the mixed solution is completely precipitated, and reacting under a heating condition to prepare FeCoOOH; and (3) dissolving FeCoOOH in ethanol, and dropwise adding the obtained solution to the etched silver electrode in the step (1) to obtain the nano etched silver electrode loaded with the transition metal catalyst. The product prepared by the method is excellent in electrode catalytic performance, and the OER performance induced by the SPR effect is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically relating to a nano-etched silver electrode supported on a transition metal catalyst, its preparation method, and its application. Background Technology

[0002] In recent years, rapid progress has been made in catalyst modification and photocatalysis research. In studies utilizing light energy to convert chemical energy and enhance the activity of the OER (oxygen evolution reaction), researchers have effectively promoted the separation and migration of photogenerated charges and expanded the light absorption range through nanostructure regulation, heterojunction construction, and loading of co-catalysts, thereby significantly improving the efficiency and stability of the photocatalytic oxygen evolution reaction. Surface plasmon resonance (SPR) is a collective charge density oscillation phenomenon occurring at the metal-dielectric interface, originating from the resonant coupling of incident photons with the free electron cloud on the metal surface. When momentum matching conditions are met, the energy of the incident light excites surface plasmons through evanescent waves, leading to a significant enhancement of the local electromagnetic field at the interface, accompanied by strong light absorption. The SPR effect, through enhanced local electric field, hot carrier injection, and local thermal effects, synergistically regulates the electrochemical reaction interface, effectively promoting reactant adsorption, accelerating electron transfer processes, and lowering the reaction energy barrier, thereby significantly improving the kinetic activity of key electrocatalytic reactions such as oxygen evolution, hydrogen evolution, and carbon dioxide reduction. The important role of the SPR effect is to enhance the activity of electrochemical reactions.

[0003] The oxygen evolution reaction (OER) is the anodic half-reaction of electrocatalytic water splitting, and its high electron transfer and slow kinetics limit its energy utilization efficiency. Among numerous non-precious metal catalysts, cobalt-based and iron-based OER catalysts have become the focus of research due to their cost advantages, abundance, and favorable electronic structures. For example, Chinese patent document CN117865242A discloses an OER electrocatalyst. The preparation method of this OER electrocatalyst is as follows: using iron salts, nickel salts, and Mn terephthalic acid coordination polymers as raw materials, NiFeMn hydroxide is prepared by interfacial atomic substitution method as an OER electrocatalyst. The NiFeMn hydroxide on the surface of the catalyst and the Mn TPA substrate synergistically enable NiFeMn to exhibit excellent OER activity and selectivity in seawater electrolytes. Chinese patent document CN120719320A discloses an OER electrocatalyst. This invention uses CNF nanoarrays as a substrate and employs a series of processes including carbonization, calcination, and water bath synthesis to grow CoWO4 / Co3W3C in situ, combined with water bath etching, to obtain a Ni(OH)2-CoWO4 / Co3W3C@CNF hierarchical heterostructure composite material. The design facilitates space charge migration between reaction interfaces, thereby improving the catalyst's OER performance. However, this patent involves numerous raw materials, resulting in high costs and complex processes.

[0004] Chinese patent document CN113134361A discloses a method for preparing an Ag / αCo(OH)₂ oxygen evolution reaction (OER) catalyst. This invention involves ultrasonically dispersing α-Co(OH)₂ in deionized water, then adding an Ag(NH₃)₂OH solution dropwise to the dispersed α-Co(OH)₂ suspension. The mixture is stirred under light-shielding conditions and then irradiated with a xenon lamp. After the reaction, the product is centrifuged, washed, and freeze-dried to obtain Ag-supported Ag / αCo(OH)₂. Due to the introduction of the noble metal Ag, the catalytic material exhibits a surface plasmon resonance (SPR) effect under laser irradiation, further enhancing the electrocatalytic OER performance. Although this invention involves the combination of the SPR effect of the noble metal Ag with a cobalt-based catalyst, there are few reports in the prior art of silver enhancing photocatalytic OER over a broad spectral range through the SPR effect. Summary of the Invention

[0005] This invention provides a method for preparing a nano-etched silver electrode supported on a transition metal catalyst. The method is simple, efficient, and mild, and the resulting electrode exhibits excellent catalytic performance, achieving SPR-induced OER performance enhancement.

[0006] The specific technical solution adopted is as follows: A method for preparing a nano-etched silver electrode supported on a transition metal catalyst includes the following steps: (1) Clean the silver substrate and use HNO3 to etch the cleaned silver substrate to obtain etched silver electrodes; (2) Add an alkaline solution dropwise to a mixed solution of soluble cobalt salt and soluble iron salt. After the mixed solution has completely precipitated, adjust the pH value of the solution to 10-11 and react under heating conditions to prepare FeCoOOH. (3) After dissolving FeCoOOH in ethanol, the resulting solution is dropped onto the etched silver electrode of step (1) to obtain the nano-etched silver electrode with the supported transition metal catalyst.

[0007] This invention first utilizes chemical etching to prepare an etched silver electrode with a nanostructure. This etched silver electrode can significantly improve the OER catalytic activity of FeCoOOH catalyst over a wide spectral range through the SPR effect.

[0008] Preferably, the silver substrate is cleaned by immersing it in acetone, dried, and then etched with HNO3 at a concentration of 3-4 M.

[0009] In a further preferred embodiment, the cleaned silver substrate is immersed in a 3-4 M HNO3 solution and stirred for 2-3 minutes. When the surface of the silver substrate changes from bright to milky white, the etching is stopped to obtain an etched silver electrode.

[0010] Preferably, the soluble cobalt salt is selected from cobalt nitrate, the soluble iron salt is selected from ferric nitrate, and the alkaline solution is NaOH solution.

[0011] More preferably, a 0.25-0.3 mol / L cobalt nitrate solution and a 0.5-0.6 mol / L ferric nitrate solution are mixed to obtain a mixed solution of soluble cobalt salt and soluble iron salt, and then a 0.8-1 mol / L NaOH solution is added dropwise.

[0012] Preferably, the reaction is carried out at a heating temperature of 70-90℃ for 40-50 h, and the product is washed and dried to obtain FeCoOOH.

[0013] Preferably, the concentration of the FeCoOOH ethanol solution is 0.1-0.2 mg / mL.

[0014] The present invention also provides a method for preparing a nano-etched silver electrode supported on a transition metal catalyst, and the nano-etched silver electrode supported on a transition metal catalyst obtained therefrom.

[0015] The present invention also provides a method for electrolyzing water, utilizing the aforementioned nano-etched silver electrode supported on a transition metal catalyst.

[0016] Furthermore, using the aforementioned nano-etched silver electrode supported on a transition metal catalyst as the working electrode, an Ag / AgCl electrode as the reference electrode, a platinum electrode as the counter electrode, and a KOH solution as the electrolyte, the working electrode is subjected to photo-irradiation during the water electrolysis process.

[0017] Furthermore, the wavelength of the light source used in the light treatment is 200-2000 nm, preferably 660-980 nm.

[0018] Although silver itself is not an ideal OER catalyst, its contribution to OER performance becomes significant when combined with an iron-cobalt catalyst and under illumination due to the surface plasmon resonance (SPR) effect of the etched silver nanostructure. Under 660 nm and 980 nm laser irradiation and simulated sunlight, Ag nanostructure electrodes significantly enhanced the OER activity of FeCoOOH. This enhancement is mainly attributed to the excitation of hot electrons near the Fermi level in the Ag nanoparticles to a surface plasmon state, where high-energy holes can effectively trap electrons from the catalyst, thereby enhancing catalytic performance. Plasmon-driven hot electron excitation promotes charge transfer between FeCoOOH and the Ag substrate, accelerating the oxidation of Fe... 2+ and Co 2+ Oxidized to active Fe 2+ / Fe 3+ and Co 2+ / Co 3+ The synergistic effect between FeCoOOH and the Ag substrate improves the photocatalytic OER efficiency. Furthermore, it enhances the ability of Fe and Co active sites to extract electrons from water, accelerating O2 production and enabling more efficient water oxidation at lower onset potentials.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The nano-etched silver electrode with supported transition metal catalyst prepared in this invention exhibits good broad-spectrum SPR-enhanced OER performance. It has excellent catalytic performance and is simple to prepare. The hot electron effect induced by surface plasmon resonance (SPR) of the nano-silver electrode significantly enhances the electrocatalytic OER performance of FeCoOOH catalyst.

[0020] (2) Under irradiation with 660 nm or 980 nm laser, FeCoOOH loaded on etched silver nano-substrate exhibits excellent electrocatalytic OER performance under alkaline conditions, with low Tafel slope and good photoresponse cycle stability.

[0021] (3) This invention utilizes the broad-spectrum SPR effect of silver nanomaterials to provide a general performance enhancement platform for various electrocatalytic oxygen evolution (OER) systems. Without changing the catalyst substrate, it can be easily integrated through a simple composite process. Under broad-spectrum excitation, the strong local electric field and energy injection generated by SPR can significantly accelerate the electrocatalytic interface reaction kinetics, thereby obtaining excellent OER activity far exceeding that of the substrate itself. Attached Figure Description

[0022] Figure 1 The XRD patterns of Ag, FeCoOOH, and FeCoOOH-Ag in Example 1 are shown.

[0023] Figure 2 The following are the characterization results of Example 1, where (a) is a TEM image of FeCoOOH; (b) is a SEM image of FeCoOOH; (c) is a SEM image of etched silver foil; (d) is a SEM image of FeCoOOH-Ag; and (e)-(h) are the elemental surface distribution images of Ag, Co, Fe and O elements in FeCoOOH-Ag, respectively.

[0024] Figure 3 The OER performance under 660 nm laser (power 2W) is shown in the following figures: (a) LSV curves of FeCoOOH-Ag and Co3O4-Ag under light and dark conditions; (b) Tafel plots of FeCoOOH-Ag and Co3O4-Ag under light and dark conditions; (c) EIS curves of FeCoOOH-Ag and Co3O4-Ag; (d) chronocurrent It curves of FeCoOOH-Ag and Co3O4-Ag under 6 light-on and light-off cycles; (e) OER performance under 660 nm laser with different powers; and (f) EIS curves of FeCoOOH-Ag under 660 nm laser with different powers.

[0025] Figure 4 The OER performance under 980 nm laser (1.5 W power) is as follows: (a) LSV curves of FeCoOOH-Ag and Co3O4-Ag under light and dark conditions; (b) Tafel plots of FeCoOOH-Ag and Co3O4-Ag under light and dark conditions; (c) EIS curves of FeCoOOH-Ag and Co3O4-Ag; (d) Timing current It curves of FeCoOOH-Ag and Co3O4-Ag under 6 light-on and light-off cycles.

[0026] Figure 5The OER performance under mercury lamp illumination is shown in the following figures: (a) LSV curves of FeCoOOH-Ag and Co3O4-Ag under light and dark conditions; (b) Tafel plots of FeCoOOH-Ag and Co3O4-Ag under light and dark conditions; (c) EIS curves of FeCoOOH-Ag and Co3O4-Ag; and (d) chronocurrent It curves of FeCoOOH-Ag and Co3O4-Ag under 6 cycles of light application and removal. Detailed Implementation

[0027] To make the objectives, features, and advantages of this invention more apparent and understandable, a detailed description is provided below through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the invention can be combined appropriately without mutual conflict.

[0028] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer. Contents not described in detail in this specification are prior art known to those skilled in the art. Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0029] Example 1: Preparation of nano-etched silver electrode supported on transition metal catalyst (1) Immerse the silver foil in acetone for 5 minutes, then dry it with nitrogen. Immerse the cleaned silver foil in freshly prepared 3.5 M HNO3 solution and stir vigorously for 2-3 minutes. When the surface of the silver foil changes from bright to milky white, stop etching, take it out and rinse it thoroughly with deionized water and ethanol. Dry it with nitrogen to obtain the etched silver electrode, and put it in a sealed container for later use.

[0030] (2) The FeCoOOH catalyst was synthesized via a hydrothermal method. First, 1 mol / L NaOH solution, 0.3 mol / L cobalt nitrate solution, and 0.6 mol / L ferric nitrate solution were prepared. The prepared cobalt nitrate and ferric nitrate solutions were mixed, and 1 mol / L NaOH solution was added dropwise to 200 mL of the cobalt nitrate and ferric nitrate mixed solution in a magnetic stirrer (3000 rpm) to ensure thorough and uniform mixing. After complete precipitation, the pH of the solution was adjusted to 10-11, and after standing for 1.5 hours, the mixed solution was poured into a 100 mL polytetrafluoroethylene-lined reactor. The reaction was carried out in a vacuum drying oven at 80°C for 48 hours. The reaction product was washed, dried, and ground to obtain FeCoOOH.

[0031] (3) Dissolve 0.0016g FeCoOOH in 8 mL of ethanol and sonicate for 30 minutes to obtain an ethanol solution of FeCoOOH. Add 15 μL dropwise to the surface of the etched silver electrode obtained in step (1) with a needle. After complete air drying, a nano-etched silver electrode loaded with a transition metal catalyst is prepared, abbreviated as FeCoOOH-Ag.

[0032] Figure 1 XRD diffraction patterns of etched silver foil, FeCoOOH, and FeCoOOH-Ag were obtained. The XRD data of FeCoOOH was consistent with JCPDS card number 50-0235, indicating that FeCoOOH has a hexagonal and cubic crystal structure. The sharp XRD diffraction peaks of FeCoOOH indicate that the sample particles have good crystallinity. The XRD data of Ag was consistent with JCPDS card number 87-0597. The strong peak at 2θ = 44.29° corresponds to the diffraction of the (200) crystal plane, indicating that the (200) crystal plane of Ag is highly parallel to the orientation of the supporting substrate. Characteristic diffraction peaks of FeCoOOH and Ag can be observed in FeCoOOH-Ag, respectively. The above results indicate that the FeCoOOH catalyst was successfully loaded onto the etched silver foil.

[0033] The morphology of the etched silver foil, FeCoOOH, and FeCoOOH-Ag was analyzed by TEM and SEM, such as... Figure 2 As shown in (a)-(d) in the image, FeCoOOH exhibits a rhombic and layered structure with an average diameter of approximately 200 nm. SEM images show FeCoOOH particles loaded onto the etched silver foil surface. Furthermore, elemental distribution images (...) Figure 2 (e)-(h) shows a uniform distribution of the four elements, with Co, Fe and O evenly distributed on the etched silver foil.

[0034] Example 2: OER performance of nano-etched silver electrode supported on transition metal catalyst The electrochemical workstation used was a CHI760E, the electrolyte was 1.0 M KOH, and the FeCoOOH-Ag prepared in Example 1 was used as the working electrode. The reference electrode was an Ag / AgCl electrode from BAS Instruments, and the counter electrode was a platinum electrode. The electrolysis process and OER performance were studied. Co3O4-Ag was used as a comparison. The Co3O4 catalyst was also synthesized via a hydrothermal method. A 1 mol / L NaOH solution and a 0.3 mol / L cobalt nitrate solution were prepared under magnetic stirring (3000 rpm). The 1 mol / L NaOH solution was added dropwise to 200 mL of cobalt nitrate solution to ensure thorough and uniform mixing. The subsequent synthesis steps of the Co3O4 catalyst were the same as those of FeCoOOH, and the synthesis steps of Co3O4-Ag were the same as those of FeCoOOH-Ag.

[0035] The light sources used in the experiment included: MDL-XD-660-3W (660 nm, maximum power output 3W), LOS-BLD-0980-1.5W (980 nm, maximum power output 1.5W), and LSB610 100 W Hg (200nm-2000nm, 150W), to study the effect of SPR on the enhancement of the OER electrocatalytic process.

[0036] In the experiment, in order to obtain the change in electrode surface temperature, a thermocouple was used to detect the reaction temperature in real time. The thermocouple was placed very close to the electrode so as to obtain the change in electrode surface temperature in real time when there is light and no light during the reaction, so as to distinguish the degree of influence of thermal effect and hot carrier.

[0037] Sample Analysis Linear sweep voltammetry (LSV) was performed at a scan rate of 0.005 V / s. The Tafel slope was calculated from the LSV curves. Electrochemical impedance spectroscopy (EIS) was used to measure the resistance of the etched silver electrode and the catalyst-Ag to analyze the process by which SPR enhances the OER catalytic performance. The test conditions were a frequency range of 0.1 Hz–106 Hz, a voltage of 1.60 V vs RHE, and an amplitude voltage of 5 mV. ECSA plots were determined by the relationship between cyclic voltammetry (CV) curves with scan rates ranging from 0.01 V / s to 0.12 V / s. Current-time (It) curves were used to test the OER stability of the catalyst-etched silver sheet system. Stability was tested through cycles of illumination and de-illumination.

[0038] First, the catalyst was irradiated with a 660 nm laser (2 W power) to perform LSV testing, and the obtained LSV curve is shown below. Figure 3As shown in (a) (ON and OFF represent light and no light, respectively), the current densities of FeCoOOH-Ag(ON) and FeCoOOH-Ag(OFF) at 1.9 V vs RHE are 192.9 mA cm⁻¹. -2 and 149.4 mA cm -2 When the current density is 10 mAcm -2 When light was applied, the voltage corresponding to FeCoOOH-Ag (ON) was 1.46 V vs RHE, and the overpotential (η) was 230 mV; after light removal, the voltage corresponding to FeCoOOH-Ag (OFF) was 1.50 V vs RHE, and the overpotential was 270 mV. The overpotential of the FeCoOOH-Ag catalyst decreased significantly with light application, indicating that the OER catalytic performance of the etched silver electrode and bimetallic FeCoOOH catalyst system was significantly improved under the SPR effect. Furthermore, as... Figure 3 As shown in (b), the Tafel slopes of FeCoOOH-Ag(ON) and FeCoOOH-Ag(OFF) are 47.1 and 52.1 mV dec, respectively. -1 The lower Tafel slope value demonstrates excellent OER performance and reduced overpotential. Furthermore, the low Tafel slope indicates that the photoexcited SPR effect can effectively enhance the reaction kinetics, a fact confirmed by EIS.

[0039] according to Figure 3 As shown in (c) of the EIS test results, FeCoOOH-Ag(ON) exhibits the smallest charge transfer resistance. Meanwhile, the ECSA plot shows that FeCoOOH-Ag has a high electrochemically active area and exposed reaction sites on the surface.

[0040] Stability is one of the important indicators of catalyst performance. To further verify the light responsiveness of FeCoOOH-Ag, the electrocatalytic stability of FeCoOOH-Ag during the light application and removal processes was studied using a potentiostatic method. The results are as follows: Figure 3 As shown in (d), under 660 nm laser light, the current density increases in less than 1 second, but decreases in less than 1 second after the light is removed. The instantaneous response of the current density during light application and removal further demonstrates that the photo-enhanced electrocatalytic OER activity mainly originates from the SPR effect excited by the etching of the silver substrate. After 6 cycles of light application and removal, the current intensity did not decrease significantly. The results indicate that this photo-responsive enhanced OER catalysis has good cycling stability.

[0041] To investigate the SPR effect of laser power on the promoting effect of FeCoOOH-Ag catalyst on water electrolysis, a surface-etched silver electrode was irradiated with a 660 nm laser, and LSV and EIS tests were performed at different powers (0 W-3 W). Figure 3 As shown in (e)-(f), when the voltage is 1.9 V vs RHE, the current densities of 1W-OFF, 1W-ON, 2W-ON, 2.5W-ON, and 3W-ON at 1.9 V vs RHE are 149.3 mA cm⁻¹. -2 168.5 mA cm -2 173.1 mA cm -2 184.8 mAcm -2 and 204.1 mA cm -2 At 10 mA cm -2 At the given current densities, the corresponding overpotentials were 270 mV, 269 mV, 266 mV, 262 mV, and 262 mV, respectively. It can be seen that with increasing laser power, the current density of the LSV curve also increases, while the overpotential of the reaction gradually decreases. According to EIS testing, the contact resistance and charge transfer resistance gradually decrease with increasing laser power, indicating that the introduction of light promotes the catalytic process of electron transport and reduces impedance. The EIS results are consistent with the LSV test results, proving that with increasing light power, the Ag-excited SPR effect effectively improves the electrochemical performance of the bimetallic catalyst FeCoOOH-Ag in the OER process. The above data indicate that the electrocatalytic OER activity enhanced by the photo-excited SPR effect is positively correlated with the increase of laser power.

[0042] To investigate the appropriate wavelength range for enhancing the OER catalytic activity through the SPR effect in the surface-etched silver electrode-catalyst system, LSV measurements were performed using a 980 nm laser with a power of 1.5 W. Other conditions remained consistent with those used for the 660 nm laser measurements. Figure 4 As shown in (a) above, it can be seen that at 1.9 V vs RHE, the current densities of FeCoOOH-Ag(ON) and FeCoOOH-Ag(OFF) are 246.6 and 149.4 mA cm⁻¹, respectively. -2 When light with a wavelength of 980 nm is applied, the LSV curve for FeCoOOH-Ag(ON) also shows a higher current density. For example... Figure 4 As shown in (b), the Tafel slopes of FeCoOOH-Ag(ON) and FeCoOOH-Ag(OFF) are 35 and 52.1 mV dec, respectively. -1 Consistent with LSV test results, such as... Figure 4As shown in (c), the radius of the Nyquist plot of FeCoOOH-Ag is significantly reduced due to the introduction of light. Figure 4 As shown in (d), for FeCoOOH-Ag, the current intensity did not significantly decrease after six cycles of illumination addition and removal. The results indicate that the photoresponse-enhanced OER catalysis of FeCoOOH-Ag exhibits good cycling stability under 980 nm laser irradiation. Due to the SPR effect, FeCoOOH-Ag exhibits lower overpotential, smaller Tafel slope, and lower charge transfer resistance. That is, the SPR effect of the surface-etched silver electrode-catalyst system enhances OER catalytic activity not only in the visible light range but also shows good photoenhancing effects in the near-infrared region.

[0043] LSV tests were performed on FeCoOOH-Ag substrates irradiated with mercury lamps (wavelength 200-2000 nm) while keeping other conditions constant. The resulting LSV curves are shown below. Figure 5 As shown in (a) above, the current density increases significantly after illumination, further demonstrating that the performance enhancement of the FeCoOOH-Ag catalyst can be achieved over a wide spectral range. It can be seen that at 1.9 V vs RHE, the current densities of FeCoOOH-Ag(ON) and FeCoOOH-Ag(OFF) are 181.9 and 149.4 mA cm⁻¹, respectively. -2 When using visible light, the LSV curve for FeCoOOH-Ag(ON) also shows a higher current density. At a current density of 10 mA cm⁻¹... -2 When the light was applied, the voltage of FeCoOOH-Ag(ON) was 1.48 V vs RHE, with an overpotential of 250 mV; after the light was removed, the voltage of FeCoOOH-Ag(OFF) was 1.50 V vs RHE, with an overpotential of 270 mV. Furthermore, as... Figure 5 As shown in (b), the Tafel slopes of FeCoOOH-Ag(ON) and FeCoOOH-Ag(OFF) are 51 and 52.1 mV dec, respectively. -1 Consistent with LSV test results, such as... Figure 5 As shown in (c), the radius of the Nyquist plot of FeCoOOH-Ag is significantly reduced due to the introduction of light. For FeCoOOH-Ag, the current intensity does not decrease significantly after 6 cycles of adding and removing light. Figure 5 (d)). The results show that, in the visible light region, the photoresponsive OER catalyzed FeCoOOH-Ag exhibits good cycling stability. Furthermore, to demonstrate the universality of the Ag substrate, electrochemical tests were performed on Co3O4-Ag under visible light. Visible light irradiation also significantly enhanced the electrocatalytic OER activity of Co3O4-Ag.

[0044] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a nano-etched silver electrode supported on a transition metal catalyst, characterized in that, Includes the following steps: (1) Clean the silver substrate and use HNO3 to etch the cleaned silver substrate to obtain etched silver electrodes; (2) Add an alkaline solution dropwise to a mixed solution of soluble cobalt salt and soluble iron salt. After the mixed solution has completely precipitated, adjust the pH value of the solution to 10-11 and react under heating conditions to prepare FeCoOOH. (3) After dissolving FeCoOOH in ethanol, the resulting solution is dropped onto the etched silver electrode of step (1) to obtain the nano-etched silver electrode with the supported transition metal catalyst.

2. The method for preparing a nano-etched silver electrode supported on a transition metal catalyst according to claim 1, characterized in that, The cleaned silver substrate is immersed in a 3-4 M HNO3 solution and stirred for 2-3 minutes. When the surface of the silver substrate changes from bright to milky white, the etching is stopped, and the etched silver electrode is obtained.

3. The method for preparing a nano-etched silver electrode supported on a transition metal catalyst according to claim 1, characterized in that, The soluble cobalt salt is selected from cobalt nitrate, the soluble iron salt is selected from ferric nitrate, and the alkaline solution is NaOH solution.

4. The method for preparing a nano-etched silver electrode supported on a transition metal catalyst according to claim 3, characterized in that, Mix a 0.25-0.3 mol / L cobalt nitrate solution with a 0.5-0.6 mol / L ferric nitrate solution to obtain a mixed solution of soluble cobalt salt and soluble iron salt, and then add a 0.8-1 mol / L NaOH solution dropwise.

5. The method for preparing a nano-etched silver electrode supported on a transition metal catalyst according to claim 1, characterized in that, The reaction was carried out at 70-90℃ for 40-50 h, and the product was washed and dried to obtain FeCoOOH.

6. The method for preparing a nano-etched silver electrode supported on a transition metal catalyst according to claim 1, characterized in that, The concentration of FeCoOOH in ethanol solution is 0.1-0.2 mg / mL.

7. The nano-etched silver electrode with a supported transition metal catalyst prepared by the method for preparing the nano-etched silver electrode with a supported transition metal catalyst according to any one of claims 1-6.

8. A method for electrolyzing water, characterized in that, Nano-etched silver electrode using the supported transition metal catalyst as described in claim 7.

9. The method for electrolyzing water according to claim 8, characterized in that, Using the nano-etched silver electrode supported on the transition metal catalyst as the working electrode, the Ag / AgCl electrode as the reference electrode, and the platinum electrode as the counter electrode, with KOH solution as the electrolyte, the working electrode was subjected to photo-irradiation during the water electrolysis process.

10. The method for electrolyzing water according to claim 9, characterized in that, The wavelength of the light source used in the light treatment is 200-2000 nm.

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