The Research On Preparation And Hydrogen Evolution Properties Of Nanoporous Ni And Ni-Co(Mo) Based Sulfides Composite Electrodes

With the rapid development of social economy,the heavy use of fossil fuels has caused a series of environmental problems,such as acid rain,haze,greenhouse effect and so on,which seriously threaten people's life and physical health.Hydrogen as a new type of secondary energy with clean and high-efficiency is increasingly attracting social's attention.At present,the preparation of hydrogen mainly use the method of electrolyzing water,due to the existence of hydrogen evolution overpotential,the energy conversion efficiency is low and the industrialization of hydrogen is limited.Therefore,it is of great significance to improve the performance of electrocatalytic hydrogen evolution of electrode materials.In this paper,the precursor alloys with the atomic percentages of Ni100-xAlx(x=70,75,80),Ni10-xCoxAl90(x=3,5,7)and Ni10-xMoxAl90(x=3,5,7)are prepared by vacuum smelting and rapid solidification.Then the nano-porous Ni,Ni-Co and Ni-Mo alloys with different morphology were obtained by dissolving A1 with 25 wt.%NaOH solution for 32 h under 65 ?.Finally,the nano-porous Ni-S/Ni,Ni-Co-S/Ni-Co and Ni-Mo-S/Ni-Mo composite electrodes with different morphology were obtained using hydrothermal reactio n.The phase,element content and micro structure of the electrode were analyzed by XRD,SEM,EDS and TEM.The results show that the skeleton structure formed by Ni30Al70 alloy after dealloying is the smallest.The phase composition of three kinds of different Co content in Ni-Co-Al alloy are Al and Co2Al9 phases,and with the increase of Co content,the skeleton structure formed after dealloying becomes smaller,the Ni3Co7Al90 precursor alloy obtains the maximum specific surface area by dealloying.In Ni-Mo-Al alloy,because the low diffusion rate of Mo atom during the process of de alloying hinders the diffusion of Ni atom,the nano-porous skeleton structure is smaller,when the content of Mo is too high,it will lead to excessive refinement of skeleton structure,resulting in partial collapse of skeleton and decrease of specific surface area.In addition,the inclusion of S elements resulted in the formation of interlaced nano-slice structures on the surface of nano-porous electrodes.The electrocatalytic properties,specific surface area and stability for hydrogen evolution reaction(HER)of each electrode in 1 mol-L-1 NaOH solution were investigated by Linear Sweep Voltammetry(LSV),Electrochemical Impedance Spectro scopy(EIS),Multi-Potential Steps(S TEP)and Chronopotentio metry(CP).The result showed that the addition of S element makes the electrocatalytic hydrogen performance of each composite electrode better than that of the substrate electrode,so it has a lower hydrogen evolution potential under the same current density.At the same time,the addition of S element improves the stability of the electrode to a certain extent.