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CN-122013235-A - Preparation method of self-supporting electrode and method for improving hydrogen production rate through pulse electrocatalysis

CN122013235ACN 122013235 ACN122013235 ACN 122013235ACN-122013235-A

Abstract

The invention discloses a preparation method of a self-supporting electrode and a method for improving hydrogen production rate by pulse electro-catalysis, wherein the preparation method is used for preparing NiFeCoP-CVP/LDH/NF heterostructure self-supporting catalyst on a foam nickel substrate by a cyclic voltammetry electro-deposition method and a pulse electro-deposition method in two steps as the electrode, and the electrode has a unique nano coral hierarchical porous structure. In alkaline electrolyte, a pulse electric field with specific parameters is applied to the anode and the cathode to carry out water electrolysis hydrogen production reaction. The pulse strategy can effectively regulate and control the electrode/electrolyte interface process, accelerate reaction kinetics in the on-state, and promote hydrogen bubble desorption and active site regeneration in the off-state, thereby remarkably improving the hydrogen production rate and the electrode stability. The invention provides an effective scheme for solving the problems of bubble shielding, limited mass transfer, poor adaptability to dynamic working conditions and the like in the traditional water electrolysis hydrogen production, and is particularly suitable for a wave-activated renewable energy driven water electrolysis hydrogen production system.

Inventors

  • ZHONG ZHAOPING
  • Qi Renzhi
  • JIA YOU
  • CHEN HUANQI

Assignees

  • 东南大学

Dates

Publication Date
20260512
Application Date
20260105

Claims (10)

  1. 1. A method of making a self-supporting electrode comprising: S1, preprocessing a foam nickel substrate; S2, constructing a vertically oriented nickel-iron-cobalt layered double hydroxide (NiFeCo-LDH) nanosheet array on a foam nickel substrate by using the pretreated foam nickel as a working electrode through a cyclic voltammetry electrodeposition method, and washing and drying the deposited electrode to obtain a NiFeCo-LDH-CV/NF precursor catalyst; And S3, using a NiFeCo-LDH-CV/NF precursor catalyst as a working electrode, adopting a pulse electrodeposition method to grow NiFeCoP nano particles on the LDH nano sheet in situ, and washing and drying the electrode after pulse deposition to obtain the NiFeCoP-CVP/LDH/NF heterostructure electrode with the nano coral-shaped hierarchical porous structure.
  2. 2. The method for preparing a self-supporting electrode according to claim 1, wherein in step S1, the pretreatment process of the foam nickel substrate comprises sequentially ultrasonic cleaning the foam nickel substrate in HCl solution, ethanol/acetone mixture, deionized water for a period of time, rinsing with deionized water, and vacuum drying.
  3. 3. The method of preparing a self-supporting electrode according to claim 1, wherein in step S2, the electrolyte used in the cyclic voltammetry deposition method is prepared by 、 And The electrolyte with the total metal ion concentration of 0.1M is prepared by dissolving Ni and Fe in deionized water according to the molar ratio of Co=2:1:1.
  4. 4. The method of claim 1, wherein in step S2, the cyclic voltammetry electrodeposition method uses a platinum sheet or a graphite rod as a counter electrode and a silver/silver chloride electrode as a reference electrode.
  5. 5. The method of preparing a self-supporting electrode according to claim 1, wherein in step S3, the electrolyte used in the pulse electrodeposition method is selected from the group consisting of 、 、 、 NaCl and Dissolving in deionized water according to a molar ratio of 3:1:1:1:1 to prepare an electrolyte with a total metal ion concentration of 0.2M.
  6. 6. The method of claim 1, wherein in step S3, the pulsed electrodeposition method uses a graphite rod as a counter electrode and a saturated calomel electrode as a reference electrode.
  7. 7. The method for preparing a self-supporting electrode according to claim 1, wherein in the step S3, parameters of a pulse electrodeposition method are that a pulse frequency is 1-10 Hz, a duty ratio is 60% -70%, and a total deposition time is 600-900S.
  8. 8. The method for preparing a self-supporting electrode according to claim 1, wherein in the step S3, the average particle size of NiFeCoP nm is 20-100 nm.
  9. 9. A method for improving hydrogen production rate by pulse electrocatalysis is characterized in that NiFeCoP-CVP/LDH/NF heterostructure electrodes obtained by the preparation method of a self-supporting electrode according to any one of claims 1 to 8 are adopted as anodes and cathodes, a pulse electric field is applied to the anodes and cathodes in alkaline electrolyte to electrolyze water to produce hydrogen, and parameters of the pulse electric field are that pulse conduction time is 1-10 s and duty ratio is 70% -80%.
  10. 10. The method of claim 9, wherein the pulsed electric field is a square wave current pulse.

Description

Preparation method of self-supporting electrode and method for improving hydrogen production rate through pulse electrocatalysis Technical Field The invention belongs to the technical field of hydrogen production by water electrolysis, relates to a preparation method of a self-supporting electrode and a method for improving hydrogen production rate by pulse electro-catalysis, and in particular relates to a method for preparing a NiFeCoP-CVP/LDH/NF heterostructure self-supporting electrode by combining a constant-current electro-deposition method and a pulse electro-deposition method, and a method for improving hydrogen production rate by using the NiFeCoP-CVP/LDH/NF heterostructure self-supporting electrode for pulse electro-catalysis hydrogen production and optimizing pulse electric field parameters. Background In the current global energy transformation background, green hydrogen is used as a key medium for realizing deep decarburization, and the large-scale preparation technology of the green hydrogen faces a great challenge. Currently, alkaline water electrolysis hydrogen production technology is still the green hydrogen production route with the most commercialized potential due to the relatively low cost. The core challenge of this technology is to develop high performance, low cost catalyst electrodes. At present, research is focused on improving the intrinsic activity and stability of the catalyst by constructing heterostructures (e.g., phosphides, hydroxides, etc.). However, such electrodes, prepared by potentiostatic/galvanostatic (e.g., electrodeposition) methods, still face the following inherent difficulties when operated in a conventional constant current electrolysis mode: The structural defect is that the potentiostatic/amperometric method is easy to cause active substances to accumulate and agglomerate to form a compact structure, prevents electrolyte from penetrating and bubble desorption, and reduces available active sites. Bubble shielding effect, namely, the constant current mode cannot effectively cope with current fluctuation input by fluctuation renewable energy sources (such as wind power and photovoltaic), so that the catalyst structure is easy to degrade and the stability is poor. The catalyst structure is designed aiming at steady-state working conditions, and has poor response capability and long-term stability under the dynamic working conditions driven by fluctuation renewable energy sources (such as wind power and photovoltaic). Pulsed electrocatalysis has been explored as an interface process dynamic regulation strategy to improve single hydrogen or oxygen evolution reactions. By precisely controlling the time sequence distribution of the potential/current, the electric double layer structure of the electrode/electrolyte interface, the adsorption behavior of the reaction intermediate and the bubble desorption kinetics are hopeful to be improved. However, the prior art has obvious defects that most researches are focused on half reaction and lack of overall consideration on cathode and anode cooperative mechanisms in a full hydrolysis system, and more importantly, the correlation design and optimization of a catalyst synthesis method (such as pulse electrodeposition) and subsequent pulse electrolysis parameters cannot be carried out, so that the improvement of hydrogen production efficiency is limited. In addition, the traditional electrode preparation method is difficult to realize high active site density and good structural stability at the same time, and limits the practical application effect of the pulse electro-catalysis technology. Therefore, developing a synergistic strategy capable of optimizing the microstructure of the catalyst and the operation performance of the catalyst under the dynamic working condition has important significance for promoting the practical application of the water electrolysis hydrogen production technology. Disclosure of Invention The first object of the invention is to provide a preparation method of a self-supporting electrode for producing hydrogen by water electrolysis, and the second object of the invention is to provide a method for improving the hydrogen production rate by pulse electro-catalysis. The preparation method of the self-supporting electrode comprises the following steps: S1, preprocessing a foam nickel substrate; S2, constructing a vertically oriented nickel-iron-cobalt layered double hydroxide (NiFeCo-LDH) nanosheet array on a foam nickel substrate by using the pretreated foam nickel as a working electrode through a cyclic voltammetry electrodeposition method, and washing and drying the deposited electrode to obtain a NiFeCo-LDH-CV/NF precursor catalyst; And S3, using a NiFeCo-LDH-CV/NF precursor catalyst as a working electrode, adopting a pulse electrodeposition method to grow NiFeCoP nano particles on the LDH nano sheet in situ, and washing and drying the electrode after pulse deposition to obtain the NiFeCoP-CVP/LDH/N