Electrochemical Preparation Of Ni-Mo And Ni/Ni?OH?₂ Thin Films For Electrocatalytic Hydrogen Evolution Reaction

Hydrogen is an ideal secondary energy,which is clean,efficient,and can be stored and transported conveniently.It is a promicing substitute for coal,oil and natural gas and other non-renewable energy.To design and prepare a cathode materials,abundant,inexpensive and with low overpotential of hydrogen evolution,has been of great practical significance.Ni-based materials are considered to be ideal ones for hydrogen evolution that can be industrialized.Therefore,it is significant to fabricate Ni-based electrodes with good activity and long-term stability for hydrogen evolution reactions(HERs).In present work,we mainly prepared Ni-based cathodes for electrocatalytic HERs.The main reserach contents are as follows:(1)We have prepared Ni-Mo coated coral-like Cu(Ni-Mo/c-Cu)micro-arrays by a two-step electrochemical method.Firstly,the coral-like Cu micro-arrays were prepared by treating the Cu electrode surface with square wave potential pulses(SWPPs)in a blank H2SO4 solution.Secondly,the thin Ni-Mo coatings were obtained by cathodic electrodeposition.The prepared Ni-Mo/c-Cu electrode possesses high electrocatalytic activity comparable to Pt for HERs in an acidic medium which is different from the Ni-Mo deposits reported previously.The stability of the prepared electrode in the acidic medium is assessed by continuous cyclic voltammetry(CV)and by chronoamperometry.The electrode can maintain high performance for a long time in the acidic medium.In addition,we also explore its storage stability.Immersing the Ni-Mo/c-Cu electrode in ethanol can effectively prevent the electrode surface from oxidation by oxygen from air during the electrode storage,which satisfactorily remains its electrocatalytic activity for HERs.(2)We have prepared Ni(OH)2/Ni nano-film coated coral-like Cu micro-arrays by electrochemical method.Firstly,Ni coatings on the coral-like Cu micro-arrays(c-Cu)were prepared by electrodeposition to get Ni/c-Cu electrode.And then,the Ni/c-Cu was processed by linear sweep voltammetry(LSV)to get Ni(OH)2/Ni/c-Cu nano-film electrode in 1 M KOH.We found that the Ni(OH)2/Ni/c-Cu nano-film electrodes possess better electrocatalytic activity for HERs than Ni/c-Cu electrodes,which indicates that Ni(OH)2 enhances activity for hydrogen evolution reaction.(3)Study of activity towards HERs in alkaline solution for the electrodes of Ni-Mo/c-Cu and Ni(OH)2/Ni/c-Cu nano-films.