Preparation method and application of anion-modified Ni-MoO2 / Cu heterostructure catalyst

Abstract

The application discloses a preparation method and application of an anion-modified Ni-MoO2 / Cu heterostructure catalyst. ‑2 The application has high catalytic efficiency on a hydrogen evolution reaction, and the overpotential of the hydrogen evolution reaction is 42 mV under a current density of 10 mA cm 2 . The catalyst can be applied to water electrolysis hydrogen production, and has high reaction activity and stability in an alkaline environment, can improve the water electrolysis hydrogen production efficiency, and has the potential to replace a noble metal catalyst.

Description

Technical Field

[0001] This application relates to a method for preparing anion-modified Ni-MoO2 / Cu heterostructure catalyst and its application, belonging to the field of nanomaterials technology. Background Technology

[0002] Electrolysis of water is an environmentally friendly hydrogen production technology that converts solar or electrical energy into chemical energy for storage. Compared to water electrolysis under acidic conditions, hydrogen production under alkaline conditions is more cost-effective for large-scale applications. However, the hydrogen evolution reaction kinetics in alkaline electrolytes are slow, resulting in a low hydrogen production rate. Therefore, developing efficient and stable electrocatalysts for the hydrogen evolution reaction is currently a hot research topic. Commercial platinum-based catalysts suffer from high costs and poor stability under high current densities. In recent years, research into inexpensive and environmentally friendly non-precious metal alternatives to platinum-based materials has become a focus. Currently, Mo-based catalysts have been proven to be one of the most promising alternatives to precious metal Pt-based catalysts. Summary of the Invention

[0003] This invention provides a method for preparing anion-modified heterostructure catalyst electrode. Using nickel metal as the conductive substrate, the active catalytic layer is prepared via hydrothermal treatment, electrodeposition, and high-temperature annealing. This catalyst exhibits good catalytic activity and stability during the hydrogen evolution reaction under alkaline conditions, demonstrating promising industrial application prospects and commercial value.

[0004] This application aims to construct an anion-modified Ni-MoO2 / Cu heterostructure hydrogen evolution catalyst. This catalyst exhibits excellent catalytic activity and stability in the catalytic reaction of alkaline hydrogen evolution under conventional three-electrode conditions.

[0005] According to one aspect of this application, a method for preparing anion-modified Ni-MoO2 / Cu heterostructure catalyst is provided, the method comprising the following steps:

[0006] (1) Pre-treat the nickel-based material by immersing it in a nitric acid solution for a period of time and then rinsing it repeatedly with deionized water to obtain the pre-treated nickel-based material.

[0007] (2) In a closed reactor, a mixture containing molybdenum salt, anionic salt solution and pretreated nickel-based material is reacted and dried to obtain anionic modified Ni-MoO2 precursor;

[0008] (3) Using the anion-modified Ni-MoO2 precursor as the cathode, electrodeposition was performed in a mixed solution containing copper sulfate and boric acid to obtain the anion-modified Ni-MoO2 / Cu precursor.

[0009] (4) The anion-modified Ni-MoO2 / Cu precursor was annealed under an inactive atmosphere to obtain the anion-modified Ni-MoO2 / Cu heterostructure catalyst.

[0010] Optionally, in step (1), the nickel-based material is selected from at least one of nickel foil, nickel foam, and nickel felt.

[0011] Optionally, the concentration of the nitric acid solution is 10 wt.% to 50 wt.%.

[0012] Optionally, the concentration of the nitric acid solution is independently selected from any value of 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, or a range between any two of the above.

[0013] Optionally, in step (1), the soaking time is 10 min to 30 min.

[0014] Optionally, the soaking time is independently selected from any value of 10 min, 12 min, 15 min, 20 min, 25 min, 30 min, or a range between any two of the above.

[0015] Optionally, in step (2), the molybdenum salt is selected from at least one of ammonium molybdate, sodium molybdate, and potassium molybdate.

[0016] Optionally, the concentration of the molybdenum salt solution is 0.01–0.1 mol / L.

[0017] Optionally, the concentration of the molybdenum salt solution is independently selected from any value among 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, and 0.1 mol / L, or a range between any two of the above.

[0018] Optionally, the anionic salt in the anionic salt solution is selected from at least one of H3BO3, NH4Cl, NH4F, and NH4PO4.

[0019] Optionally, the concentration of the anionic salt solution is independently selected from any value among 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, and 2 mol / L, or a range between any two of the above.

[0020] Optionally, the molar ratio of the molybdenum salt to the anionic salt solution is 0.01-1:0.2-2, and the molar amount of the anionic salt solution is expressed as the molar amount of the anionic salt.

[0021] Optionally, in step (2), the reaction temperature is 150-200°C and the reaction time is 10-30 h.

[0022] Optionally, in step (2), the temperature of the reaction is independently selected from any value of 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or a range between any two of the above.

[0023] Optionally, in step (2), the reaction time is independently selected from any value of 10h, 15h, 20h, 25h, 30h or a range between any two of the above.

[0024] Optionally, the drying temperature is 40–80°C, and the drying time is 6–24 hours.

[0025] Optionally, in step (3), the concentration of copper sulfate is 0.005 to 0.1 mol / L.

[0026] Optionally, in step (3), the concentration of copper sulfate is independently selected from any value among 0.005 mol / L, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, or any range between the two.

[0027] Optionally, the concentration of the boric acid is 0.01 to 0.1 mol / L.

[0028] Optionally, in the electrodeposition process, the ratio of copper sulfate to boric acid in the deposition solution is 0.005–0.1:0.01–0.1.

[0029] Optionally, in step (3), the deposition current during the electrodeposition process is -2 to -10 mA cm⁻¹. -2 .

[0030] Optionally, the deposition time during the electrodeposition process is 200–400 s.

[0031] Optionally, the deposition time during the electrodeposition process is independently selected from any value of 200s, 220s, 250s, 280s, 300s, 350s, 380s, 400s or a range between any two of the above.

[0032] Optionally, in step (4), the annealing temperature is independently selected from any value of 300℃, 350℃, 400℃, 450℃, 500℃ or a range between any two of the above.

[0033] Optionally, in step (4), the annealing time is independently selected from any value of 1h, 2h, 3h, 4h or a range between any two of the above.

[0034] Optionally, the heating rate during the annealing process is 2 to 10 °C / min.

[0035] Optionally, in step (4), the inactive atmosphere is selected from at least one of argon and nitrogen.

[0036] According to another aspect of this application, an anion-modified Ni-MoO2 / Cu heterostructure catalyst prepared by the preparation method described above is provided.

[0037] According to another aspect of this application, the application of the anion-modified Ni-MoO2 / Cu heterostructure catalyst described above in the catalytic electrochemical hydrogen evolution reaction is provided.

[0038] According to a fourth aspect of this application, a highly efficient and stable catalyst for hydrogen production by water electrolysis is provided, wherein a three-electrode assembly is used to test the hydrogen evolution by water electrolysis in an alkaline electrolyte solution, wherein the three-electrode assembly includes a working electrode, a counter electrode and a reference electrode, and the electrolyte is a 1M potassium hydroxide solution.

[0039] As an optional implementation, this application is achieved through the following technical solution:

[0040] A method for preparing anion-modified oxide and metal heterostructure catalysts includes the following steps:

[0041] 1) Using commercially available nickel foam (NF, 2.5×3.5cm) 2 Using NF as a substrate, it was ultrasonically cleaned for 15 min in sequence with acetone, ethanol, 1 mol / L HNO3 solution and deionized water to obtain the cleaned NF.

[0042] 2) Weigh 2.47 g of ammonium heptamolybdate tetrahydrate, add 30 mL of deionized water, and stir for 20 min to obtain a clear solution. Add the stirred solution and pretreated nickel foam to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene, and react at 180 °C in an oven for 16 hours. After the reaction is complete and the temperature is allowed to drop naturally, remove the nickel foam from the reactor, rinse with plenty of water and ethanol, and then place the sample in a forced-air drying oven to dry for 6 hours.

[0043] 3) Using electrochemical deposition, with the sample from step 2) as the conductive support and catalyst support, in a freshly prepared electrodeposition precursor solution (composed of 10 mmol / L anhydrous copper sulfate + 50 mmol / L boric acid), at a current of -5 mA cm⁻¹. -2 Electrodeposition was performed for 300 s to obtain the Ni-MoO2 / Cu material precursor in situ.

[0044] 4) Place the Ni-MoO2 / Cu precursor obtained in the previous step into a tube furnace. Fill the furnace with high-purity argon as a protective gas and continuously purge at a flow rate of 150 ml / min for 30 minutes to purge the oxygen from the furnace. After purging, adjust the flow rate to 80 ml / min and raise the temperature to 400℃ at a rate of 5℃ / min, maintaining this temperature for 2 hours. After the reaction has completed and the temperature has naturally cooled, remove the sample to obtain the final product.

[0045] Optionally, in step 2), prepare an aqueous solution of nickel acetate tetrahydrate and ammonium heptamolybdate tetrahydrate, stir it evenly, add urea and continue stirring until the solution turns into a clear and transparent light green color; add the stirred solution and the pretreated foamed nickel to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene, and react in an oven at 150-200 degrees Celsius for 15-30 hours.

[0046] Optionally, in step 2), after the reaction is completed and the temperature drops naturally, the foam in the reaction vessel is removed, and the sample is cleaned with a large amount of water and ethanol before being placed in a vacuum drying oven to dry for 6 to 8 hours.

[0047] Optionally, in step 4), the obtained sample is placed in the center of a tube furnace and heated to 400±20℃ in a nitrogen or argon atmosphere at a heating rate of 1-5℃ / min and held for 1-5 hours.

[0048] This application provides a method for preparing anion-modified Ni-MoO2 / Cu heterostructure catalyst and its application. This invention exhibits high catalytic efficiency for the hydrogen evolution reaction (HER), with the HER reaction occurring at 10 mA cm⁻¹. -2 At a given current density, the overpotential is 42 mV. This catalyst can be used for hydrogen production via water electrolysis, exhibiting high catalytic activity and stability under alkaline conditions. It can improve the efficiency of hydrogen production via water electrolysis and has the potential to replace precious metal catalysts.

[0049] The beneficial effects that this application can produce include:

[0050] 1) The method for preparing the anion-modified Ni-MoO2 / Cu heterostructure catalyst provided in this application can adjust the hydrogen evolution activity of the catalyst by adding different anion salt solutions.

[0051] 2) The preparation method provided in this application obtains a highly active and stable electrode system by changing parameters such as the composition, concentration, reaction temperature, and reaction time of the reaction solution, thereby meeting different requirements for catalytic performance.

[0052] 3) The integral electrode provided in this application is based on nickel foam, which has the advantages of excellent conductivity and large specific surface area, which is beneficial to the transfer of electrons and protons in the reaction and the improvement of catalyst loading.

[0053] 4) The in-situ preparation method provided in this application facilitates a close bond between the catalyst and the conductive support, thereby improving its charge transport characteristics and mechanical stability, which is crucial in industrial applications. Attached Figure Description

[0054] Figure 1 These are SEM images of Ni-MoO2 / Cu prepared in Example 1 of this application at different magnifications.

[0055] Figure 2 These are TEM images of the sample in Example 1 of this application at different magnifications.

[0056] Figure 3 This is a TEM elemental distribution map of the sample in Example 1 of this application.

[0057] Figure 4 This is a graph showing the hydrogen evolution activity of the sample from Example 1 of this application and a commercial Pt / C catalyst in an alkaline electrolyte. The horizontal axis represents the standard hydrogen electrode voltage (V vs RHE), and the vertical axis represents the current density (mA / cm²). 2 ).

[0058] Figure 5 This is the constant current Vt curve of the sample in Example 1 of this application in a 1 mol / L KOH electrolyte solution. Detailed Implementation

[0059] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0060] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0061] This application uses a GeminiSEM 300 scanning electron microscope to measure the microstructure of the active material in the catalyst.

[0062] The lattice spacing of the active material in the catalyst was measured using a JEM 2100F transmission electron microscope.

[0063] The hydrogen evolution performance was characterized using a Koster electrochemical workstation. The hydrogen evolution activity of the prepared catalyst was tested by measuring electrochemical polarization curves and galvanostatic curves.

[0064] Example 1

[0065] Step 1: Using commercially available nickel foam (NF, 2×2cm) 2 Using acetone, ethanol, 1 mol / L HNO3 solution and deionized water as a substrate, the substrate was ultrasonically cleaned for 15 min in sequence to obtain the cleaned NF (pretreated nickel foam).

[0066] Step 2: Weigh 2 mmol, 2.47 g of ammonium heptamolybdate tetrahydrate, and 40 mmol of ammonium fluoride into 30 mL of deionized water and stir for 20 min to obtain a clear solution. Add the stirred solution and pretreated nickel foam to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene and react at 180 °C for 16 hours in an oven. After the reaction is complete and the mixture cools naturally, remove the nickel foam from the reactor, rinse it with plenty of water and ethanol, and then place the sample in a forced-air drying oven at 50 °C for 6 hours.

[0067] Step 3: Using electrochemical deposition, with the sample from Step 2 as the conductive support and catalyst support, in 100 ml of freshly prepared electrodeposition precursor solution (the precursor solution consists of 1 mmol, 0.16 g anhydrous copper sulfate + 5 mmol, 0.31 g boric acid), at a current of -5 mA cm⁻¹. -2 Electrodeposition was performed for 300 s to obtain the Ni-MoO2(F) / Cu material precursor in situ.

[0068] Step 4: Place the precursor obtained in Step 3 into a tube furnace, and fill the furnace with high-purity argon as a protective gas. Continuously purge the furnace with argon at a flow rate of 150 ml / min for 30 minutes to purge the oxygen. After purging, adjust the flow rate to 80 ml / min and raise the temperature to 400℃ at a rate of 5℃ / min, maintaining this temperature for 2 hours. After the reaction has finished and the temperature has naturally cooled, remove the sample to obtain the final product.

[0069] like Figure 1 As shown, the SEM image of the sample prepared in Example 1 shows that it has a nanosheet array morphology.

[0070] like Figure 2 As shown, the TEM image of the sample prepared in Example 1 shows that it has a heterogeneous interface of Cu and MoO2.

[0071] like Figure 3 As shown in the TEM elemental distribution diagram of the sample prepared in Example 1, Ni, Mo, Cu, O, and F elements are uniformly distributed.

[0072] like Figure 4 As shown, the sample prepared in Example 1 exhibited excellent alkaline hydrogen evolution performance, and the anion F modification greatly improved the catalytic performance of the catalyst.

[0073] Example 2:

[0074] Step 1: Using commercially available nickel foam (NF, 2.5×3cm) 2 Using acetone, ethanol, 1 mol / L HNO3 solution and deionized water as the substrate, the pretreated nickel foam was ultrasonically cleaned for 15 min in sequence with acetone, ethanol, 1 mol / L HNO3 solution and deionized water to obtain pretreated nickel foam.

[0075] Step 2: Weigh 2 mmol, 2.47 g of ammonium heptamolybdate tetrahydrate and 40 mmol of ammonium chloride, add 30 mL of deionized water, and stir for 20 min to obtain a clear solution. Add the stirred solution and pretreated nickel foam to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene, and react at 180 °C in an oven for 16 hours. After the reaction is complete and the mixture cools naturally, remove the nickel foam from the reactor, rinse with plenty of water and ethanol, and then place the sample in a forced-air drying oven to dry for 6 hours.

[0076] Step 3: Using electrochemical deposition, with the sample from Step 2 as the conductive support and catalyst support, in 100 ml of freshly prepared electrodeposition precursor solution (the precursor solution consists of 1 mmol, 0.16 g anhydrous copper sulfate + 5 mmol, 0.31 g boric acid), at a current of -5 mA cm⁻¹. -2 Electrodeposition was performed for 300 s to obtain the Ni-MoO2(Cl) / Cu material precursor in situ.

[0077] Step 4: Place the MoO2(Cl) / Cu precursor synthesized in Step 3 into a tube furnace. Purge the furnace with high-purity argon as a protective gas at a flow rate of 150 ml / min for 30 min to purge oxygen from the furnace. After purging, adjust the flow rate to 80 ml / min and raise the temperature to 400℃ at a rate of 5℃ / min, maintaining this temperature for 2 hours. After the reaction has completed and the temperature has naturally cooled, remove the sample to obtain the final product.

[0078] Example 3:

[0079] Step 1: Using commercially available nickel foam (NF, 2.5×3.5cm) 2 Using acetone, ethanol, 1 mol / L HNO3 solution and deionized water as the substrate, the pretreated nickel foam was ultrasonically cleaned for 15 min in sequence with acetone, ethanol, 1 mol / L HNO3 solution and deionized water to obtain pretreated nickel foam.

[0080] Step 2: Weigh 2 mmol, 2.47 g of ammonium heptamolybdate tetrahydrate and 40 mmol of boric acid, add 30 mL of deionized water, and stir for 20 min to obtain a clear solution. Add the stirred solution and pretreated nickel foam to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene, and react at 180 °C in an oven for 16 hours. After the reaction is complete and the mixture cools naturally, remove the nickel foam from the reactor, rinse with plenty of water and ethanol, and then place the sample in a forced-air drying oven at 60 °C for 6 hours.

[0081] Step 3: Using electrochemical deposition, with the sample from Step 2 as the conductive support and catalyst support, in 100 ml of freshly prepared electrodeposition precursor solution (the precursor solution consists of 1 mmol, 0.16 g anhydrous copper sulfate + 5 mmol, 0.31 g boric acid), at a current of -5 mA / cm². -2 Electrodeposition was performed for 300 s to obtain the Ni-MoO2(B) / Cu material precursor in situ.

[0082] Step 4: Place the precursor obtained in Step 3 into a tube furnace, and fill the furnace with high-purity argon as a protective gas. Continuously purge the furnace with argon at a flow rate of 150 ml / min for 30 minutes to purge the oxygen. After purging, adjust the flow rate to 80 ml / min and raise the temperature to 400℃ at a rate of 5℃ / min, maintaining this temperature for 2 hours. After the reaction has finished and the temperature has naturally cooled, remove the sample to obtain the final product.

[0083] Comparative Example 1:

[0084] Step 1: Using commercially available nickel foam (NF, 2×2cm) 2 Using acetone, ethanol, 1 mol / L HNO3 solution and deionized water as a substrate, the substrate was ultrasonically cleaned for 15 min in sequence to obtain the cleaned NF (pretreated nickel foam).

[0085] Step 2: Weigh 2 mmol (2.47 g) of ammonium heptamolybdate tetrahydrate, add 30 mL of deionized water, and stir for 20 min to obtain a clear solution. Add the stirred solution and pretreated nickel foam to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene, and react at 180 °C in an oven for 16 hours. After the reaction is complete and the mixture cools naturally, remove the nickel foam from the reactor, rinse it with plenty of water and ethanol, and then place the sample in a forced-air drying oven at 60 °C for 6 hours.

[0086] Step 3: Using electrochemical deposition, with the sample from Step 2 as the conductive support and catalyst support, in 100 ml of freshly prepared electrodeposition precursor solution (the precursor solution consists of 1 mmol, 0.16 g anhydrous copper sulfate + 5 mmol, 0.31 g boric acid), at a current of -5 mA cm⁻¹. -2Electrodeposition was performed for 300 s to obtain the Ni-MoO2 / Cu material precursor in situ.

[0087] Step 4: Place the Ni-MoO2 / Cu precursor synthesized in Step 3 into a tube furnace. Fill the furnace with high-purity argon as a protective gas and continuously purge at a flow rate of 150 ml / min for 30 min to purge the oxygen from the furnace. After purging, adjust the flow rate to 80 ml / min and raise the temperature to 400℃ at a rate of 5℃ / min, maintaining this temperature for 2 hours. After the reaction has completed and the temperature has naturally cooled, remove the sample to obtain the final product.

[0088] Test Example 1

[0089] A composite electrode system containing Ni-MoO2(F) / Cu was prepared according to the method in Example 1, and its hydrogen evolution performance was tested under laboratory conditions (1 mol / L KOH, room temperature). It exhibited excellent activity and stability in catalyzing the electrochemical hydrogen evolution reaction. The most active catalyst showed a current density of 10 mA cm⁻¹ in 1 mol / L KOH solution at room temperature. -2 Only an overpotential of 42mV is required, and it is within 200mA / cm. 2 and 500mA cm -2 After 240 hours of stable operation, there was no significant activity degradation. Figure 5 As shown, the sample prepared in Example 1 exhibited excellent alkaline hydrogen evolution stability.

[0090] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing anion-modified Ni-MoO2 / Cu heterostructure catalyst, characterized in that, The preparation method includes the following steps: (1) The nickel-based material is pretreated to obtain the pretreated nickel-based material; (2) In a closed reactor, the pretreated nickel-based material is placed in a mixed solution containing molybdenum salt and anionic salt, and subjected to hydrothermal reaction and drying to obtain anionic modified Ni-MoO2 precursor; (3) Using the anion-modified Ni-MoO2 precursor as the cathode, electrodeposition was performed in a mixed solution containing copper sulfate and boric acid to obtain the anion-modified Ni-MoO2 / Cu precursor. (4) The anion-modified Ni-MoO2 / Cu precursor was annealed under an inactive atmosphere to obtain the anion-modified Ni-MoO2 / Cu heterostructure catalyst. The nickel-based material is selected from at least one of nickel foil, nickel foam, and nickel felt; The anionic salt is selected from at least one of H3BO3, NH4Cl, and NH4F.

2. The preparation method according to claim 1, characterized in that, In step (2), the molybdenum salt is selected from at least one of ammonium molybdate, sodium molybdate, and potassium molybdate; The concentration of the molybdenum salt solution is 0.01~0.1 mol / L; The concentration of the anionic salt in the mixed solution is 0.2~2 mol / L; The molar ratio of the molybdenum salt to the anionic salt is 0.01~1:0.2~2.

3. The preparation method according to claim 1, characterized in that, In step (2), the temperature of the hydrothermal reaction is 150~200℃ and the reaction time is 10~30h; The drying temperature is 40~80℃, and the drying time is 10~24h.

4. The preparation method according to claim 1, characterized in that, In step (3), the concentration of copper sulfate is 0.005~0.1mol / L; The concentration of the boric acid is 0.01~0.1 mol / L; In the electrodeposition process, the ratio of copper sulfate to boric acid in the deposition solution is 0.005~0.1:0.01~0.

1.

5. The preparation method according to claim 1, characterized in that, In step (3), the deposition current during the electrodeposition process is -2 to -10 mA cm⁻¹. -2 ; The deposition time during the electrodeposition process is 200~400s.

6. The preparation method according to claim 1, characterized in that, In step (1), the pretreatment involves soaking the sample in a solution containing nitric acid. The concentration of the nitric acid is 10~50 wt%; The soaking time is 10-30 minutes.

7. The preparation method according to claim 1, characterized in that, In step (4), the annealing temperature is 300 ~ 500℃ and the annealing time is 1 ~ 4h; The heating rate during the annealing process is 2~10℃ / minute.

8. The preparation method according to claim 1, characterized in that, In step (4), the inactive atmosphere is selected from at least one of argon and nitrogen.

9. The anion-modified Ni-MoO2 / Cu heterostructure catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the anion-modified Ni-MoO2 / Cu heterostructure catalyst according to claim 9 in the catalytic electrochemical hydrogen evolution reaction.

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