Preparation Of Self-Supporting Ni-P Catalytic Electrode And Study On Its Hydrogen Evolution Performance

At present,due to the consumption of fossil energy and its adverse impact on the ecological environment,the development of new environmentally friendly renewable energy has become an urgent task in the field of natural science.Hydrogen（H₂）is considered to be the most potential clean energy carrier because of its high energy density.It is very important to develop efficient and low-cost hydrogen production technology.Electrochemical decomposition of water to hydrogen can make full use of secondary energy to realize the high purity preparation of H₂,and the selection of catalyst is the key to the preparation of H₂.At present,platinum and platinum-based materials are recognized as the most effective HER catalysts,but the high price and scarce resources limit its large-scale application.Considering the catalytic performance and cost,the self-supporting Ni-P catalyst with high efficiency and low cost has a better application prospect.The main research contents are as follows:1.Ni-P/NF catalytic electrode:The effects of Ni/P and CV deposition cycles on the hydrogen evolution activity of Ni-P/NF catalytic electrode were studied by control variate method.Based on the experimental results,the optimum deposition conditions of HER electrocatalytic performance were obtained:Ni/P=1/6 and CV deposition cycles was 14 cycles.The Ni-P/NF catalytic electrode prepared under the optimum deposition conditions has excellent electrocatalytic hydrogen evolution activity:The HER overpotentials is 102mV in alkaline condition and 110mV in acidic condition.The Tafel slopes are 92.7mV/dec and 100.4mV/dec,respectively.2.Co（Fe）-Ni-P/NF catalytic electrode:Cobalt and iron are doped on the basis of the preparation of Ni-P/NF catalytic electrode,so Co-Ni-P/NF and Fe-Ni-P/NF catalytic electrodes were prepared respectively.The effects of nickel-cobalt ratio and nickel-iron ratio on the hydrogen evolution activity of the catalytic electrode were studied by control variate method.The optimum doping ratio was found to be 7/3 for nickel-cobalt ratio and 2/1 for nickel-iron ratio.The catalytic electrode materials prepared under the optimum doping ratio have excellent electrocatalytic hydrogen evolution activity:The HER overpotentials of Co-Ni-P/NF in alkaline and acidic conditions are only 71mV and 81mV,respectively.The HER overpotentials of Fe-Ni-P/NF catalytic electrode under alkaline and acidic conditions are 85mV and94mV,respectively.3.Fe-Co-Ni-P/NF catalytic electrode:the preparation conditions of Co-Ni-P/NF were optimized and iron was added to the deposition system of Co-Ni-P/NF.By finally optimizing the catalytic performance of Fe²⁺and CV deposition cycles,The results showed that when the concentration of Fe²⁺was 0.05mol/L and CV cycles was12 cycles,the hydrogen evolution activity of Fe-Co-Ni-P/NF catalytic electrode was the best:The HER overpotentials in alkaline and acidic conditions was 57mV and66mV,respectively.The Tafel slopes are 47.8mV/dec and 66.1mV/dec,respectively.4.The mechanism of a series of nickel-phosphorus catalytic electrodes in hydrogen evolution of electrolytic water was discussed by SEM,EDX and XRD,combined with electrochemical characterization.First of all,the porous structure of nickel foam itself makes its specific surface area large,which provides enough space for the loading of catalyst and the growth of active sites for hydrogen evolution.Secondly,the electrode materials of Ni-P/NF,Co-Ni-P/NF,Fe-Ni-P/NF and Fe-Co-Ni-P/NF prepared by electrodeposition are amorphous,and the active hydrogen atoms have lower adsorption energy on the surface of catalytic electrode.Thus,the rate of electrocatalytic hydrogen evolution was increased.Finally,in the process from monometallic phosphide to ternary metal phosphide,the doping of cobalt and nickel elements into the nickel-phosphorus system can promote the increase of the catalytic active sites of the catalytic electrode material,The second can effectively reduce the charge transfer resistance between the catalytic electrode and the electrolyte in the process of electrocatalytic reaction,improve the charge transfer rate of the catalytic electrode,and thus improve the electrocatalytic hydrogen evolution activity of the electrode material.