Rapid Preparation And Electrochemical Properties Of Selfsupported Nickel-based Electrode

The extraordinary increase in the consumption of carbonaceous fossil fuels and their negative impacts on the environment and health have triggered research into new renewable energy systems.Electrocatalytic water splitting as one of the most promising preparation methods has attracted extensive attention in the field.The key point lies in the selection of suitable catalysts to lower their reaction energy barriers and improve the production efficiency.Transition metal nickel-based materials are considered to be one of the most promising solutions to replace precious metal catalysts because of their low cost and easily regulated electronic structures.Compared with the single metal system,using the synergism between metal cations with different d-band centers,binary or multicomponent self-supporting nanostructures were constructed in situ on the current collector,which can further adjust the electronic properties and adsorption energy of the intermediates and improve the catalytic activity.More importantly,the electrode needed for industrial water electrolysis often has a short replacement cycle and large size,which puts forward high requirements for production speed.However,the traditional methods of synthesizing catalyst materials generally require the introduction of higher temperature and pressure.In addition,the preparation cycle is long,the technology is complex,and the size of the substrate is limited.Therefore,it is significant to develop a method for the preparation of electrocatalysts with high efficiency,energy saving and batch production.Regarding the issue above,in this paper,transition metal nickel instead of noble metal will be selected as the self-supporting substrate to construct binary and multivariate composite systems using corrosion engineering in the hope of achieving the rapid and large-scale preparation of high-performance self-supporting nickel-based electrode.The rapid preparation of self-supporting Ni Zr-OH/NF electrode was realized by optimizing the electrochemical corrosion environment of zirconium salt.The formation of uniform nano-morphology and highly catalytic active species is due to the spontaneous electrochemical oxygen absorption corrosion and the recombination of nickel-zirconium bimetallic elements.The local cation binding energy distribution is changed due to the synergistic effect of Ni/Zr elements at different d-band center energy levels,which can shift the Ni²⁺toward lower binding energy.Ultimately,the bilateral overpotential is only 154.1 m V and 290.0 m V at the current density of 10 m A cm^-2.The overall water splitting overpotential is only 1.67 V,which shows excellent performance.In order to further optimize the corrosion system and shorten the reaction time,the rapid preparation of self-supporting（Fe,Ni）OOH/NF electrode with high catalytic activity on the side of OER was achieved by enhancing the electrochemical corrosion environment via Fe ions.The bimetallic synergistic effect produced by Fe/Ni ions led to the increase of electron density near Fe and shift of Ni²⁺to high binding energy.The strong oxidation of Fe³⁺and the strong depolarization of Cl^-change the local electronic environment of the nanostructures microscopically and regulate the reaction progress macroscopically,so that both the thermodynamic and kinetic conditions of the overall corrosion are optimized and elevated.Eventually,only an overpotential of 235.0 m V is required to reach 10 m A cm^-2 on the side of OER.Further,the ternary composite electrochemical corrosion system was designed to realize the rapid preparation of bilateral highly catalytically active self-supporting（Fe,Ni,Zr）OOH/NF electrode.The multi metal synergistic effect optimized the electronic structure of the system,such that the electron density near the Fe atom increased and Fe³⁺shifted toward lower binding energy.The density of states increases near the Fermi leval,the band gap decreases,and the charge transport ability is enhanced.Eventually only the overpotential of 150.7 m V and 231.0 m V are required to reach 10 m A cm^-2 on the side of HER and OER,respectively,and the bilateral electrocatalytic performance is excellent.With the latent nature of the bifunctional nanoelectrocatalyst,the overpotential of overall water splitting is only 1.63 V at 10 m A cm^-2,and the catalytic performance is excellent,showing its competitiveness among homogeneous electrocatalysts.