| Hydrogen,as the clean and sustainable fuel with the higher specific energy density,is considered to be one of the most promising altenative energy sources to fossil fuels.Cathodic reaction of water splitting（hydrogen evolution reaction,HER）is one of the important methods to produce high purity hydrogen,while the research of HER high-efficiency electrocatalysts is the key.Although Pt-based catalysts exhibit excellent electrocatalytic activity for HER,their industrial applications are hindered by the rarity and high cost.In these years,some non-noble metal cobalt-based phosphides have undergone rapid development as electrocatalysts for HER.A series of electrode materials,which included Co-P@Ni,Co-Mo-P@Ni,Co-Mo-P@nano-porous silver（NPS）@Ni,were prepared to get high efficiency,cheap catalysts as a replacement of noble metal platinum.SEM,XRD,EDS and XPS were used to characterize the composition and microstructure of the catalysts.Linear sweep voltammetry,cyclic voltammograms,chronoamperometry and electrochemical impedance tests were also used to analysis the electrochemical performance of these materials in HER.The electrodeposition methods were used to get Co-P on metal Ni substrate.With exploring the process conditions in the method,Co-P@Ni with optimized performance of catalytic activity in hydrogen evolution were gotten.On this basis,with sodium molybdate as the Mo source in the plating solution,Co-Mo-P@Ni electrode materials were obtained by electrodeposition method.In 1 mol·L-1 KOH solution,Co-Mo-P@Ni were tested to research the performance of electrocatalytic HER activities.The experimental results show that the synergistic effect between Co and Mo enhances the hydrogen evlution performance.The Co-Mo-P electrode shows a lower overpotential of 112mV（255mV for Co-P）at a current density of 10 mA·cm-2and a smaller Tafel slope of 91 mV·dec-1(134 mV·dec-1 for Co-P).And the Co-Mo-P electrode also shows good long-term stability in alkaline solution by chronoamperometry and the CV scan of the 5000 cycles.The nano-porous silver structure was prepared by electrodeposition of silver–tin alloy on the surface of the nickel sheet,and then Sn was moved away by de-alloying,after that,Co-Mo-P were electrodeposited onto the surface of the nano-porous silver.The results show that the hydrogen evolution overpotential of Co-Mo-P@NPS@Ni is 36 mV lower than that of Co-Mo-P@Ni at 10 mA·cm-2,but the overpotential at 100 mA·cm-2 tends to be the same.From the data of the electic double layer capacitance calculated from CV curve,it can be seen that Co-Mo-P@NPS@Ni has a larger electrochemical active area and more active sites for HER than Co-Mo-P@Ni.And Co-Mo-P@Ni has good stability. |
