Preparation And Electrocatalytic Properties Of Ni-Fe-Mo System Alloy Porous Electrode Materials

As a secondary energy,hydrogen is considered as the most ideal energy carrier for its clean,high efficiency,storability and transportability.Among all of the approaches for the synthesis of hydrogen,water electrolysis has been widely used because of its environmental friendly,high efficiency and considerable product purity.Ni-based porous materials through a variety of alloying elements,designing appropriate pore structure,is conducive to form gas channel,and can improve the specific surface area of the material,thus increasing the activity of catalytic reaction center.Therefore,it is necessary to study the structure and electrochemical hydrogen analysis of Ni-based porous materials.Objective of this work is to investigate the organizational structure and electrochemical properties of porous Ni-Fe-Mo and Ni-Fe-Mo-C-LaNi5 electrodes materials using cathodic polarization,cyclic voltammetry(CV),impedance spectroscopy techniques(EIS),Scanning Electron Mircosope(SEM),X-Ray Diffration(XRD)and Back-Scatter(ed)Electron Diffraction(BSED).Electrochemical workstation is used to measure the electrochemical performance.The research work gets the following results:(1)Ni-Fe-Mo porous electrode materials consists of three parts,the most solid solution for Ni-Fe-Mo with a small amount of Mo,a small number of large area of Mo reunion,and part of the solution for a large number of NiMo compounds and small amounts of FeMo solid solution.The porous material with a composition of 8:1:1 and sintering temperature of 800 ? has good electrochemical hydrogen and its exchange current density is 2.89×10-4 A·cm-2 at room temperature.(2)The porous Ni-Fe-Mo-C-LaNis composite electrode materials has a large porosity of 35.1%,the mean pore size of 3.7?m and a larger specific surface area.The electricity analytical control step of electrode is electrochemical hydrogen reaction,and the exchange current density is 1.13×10-3 A·cm-2 at 358K.The apparent energy of activation obtained from an Arrhenius plot for the porous Ni-Fe-Mo-C-LaNis composite electrodes has been calculated to be 20.75 KJ/mol.The intrinsic catalytic activity of porous Ni-Fe-Mo-C-LaNis composite electrode is about 1.5 times that of pure Ni electrode,and the specific surface area activated is pure Ni electrode 9 times.The results suggest that the significant catalytic performance is not only from the increase of the intrinsic catalytic effect,but also from the real surface area of the cathode materials.(3)The electrochemical impedance(EIS)experiment of 6 M KOH solution at 323K temperature showed that the porous Ni-Fe-Mo-C-LaNi5 composite electrode materials has excellent electrocatalytic activity in the HER.The synergistic effects of Ni,Fe,Mo and C,as well as the hydrogen storage effect of LaNis to enhance the H adsorption on the electrode surface,are the internal reasons for the enhanced activity of electrocatalytic hydrogen evolution.Moreover,the current for porous Ni-Fe-Mo-C-LaNi5 composite electrodes increases 25%after 1000 cycles,which suggests that porous Ni-Fe-Mo-C-LaNis composite electrodes has higher electrochemical stability for hydrogen evolution.