Ni-Co-LaNi5复合电极材料在碱性介质中的电催化析氢性能

电催化析氢反应是电能向化学能转化的一个有效途径,是电化学科学中一个非常值得深入研究的课题。阴极析氢超电势的降低,是提高析氢活性,降低电解能耗的关键。为了提高电极的电催化活性,一是可通过提高电极表面的真实表面积,来降低电解过程中电极表面的真实电流密度,达到降低析氢超电势的目的;另一发展方向是提高电极材料本身的电化学活性,即寻找高催化活性的新型析氢材料犤1犦。由于过渡金属具有特殊的d电于结构,是目前公认的电化学活性最好的电极材料,而在过渡金属中,Ni及Ni合金将是研究的主要方向,其中多元合金复合材料将成为该技术发展…

Electrocatalytic Behavior of the Codeposited Ni-Co-LaNi5 Coatings for Hydrogen Evolution in Alkaline Medium

Composite coatings of Ni-Co-LaNi₅, prepared by electrolytic codepositon of Ni-Co alloys and LaNi₅ particles from a sulfamate electrolyte were investigated in view of its possible application as electrocatalytic materials for the hydrogen evolution reaction(HER). The surface morphology and microstructure of Ni-Co-LaNi₅ coatings were ob-served by means of SEM and XRD. Electrocatalytic efficiency was evaluated on the basis of electrochemical steady-state Tafel polarization and electrochemical impedance spectroscopy technology in 1mol·L^-1 NaOH solu-tion. The results were compared with Ni-Co and Ni electrodes. The real electrochemical area was estimated by apparent double-layer capacitances to account for the large difference in roughness factor of the three surfaces. The values obtained for the apparent energy of activation were 32.48kJ·mol^-1,46.29kJ·mol^-1 and 57.03kJ·mol^-1 for the HER on the Ni-Co-LaNi₅, Ni-Co and Ni electrodes, respectively. The composite coatings Ni-Co-LaNi₅ is catalytically more active than Ni and Ni-Co electrodes due to the increase in its real surface areas and the decrease in the apparent energy of activation caused by electrocatalytic synergistic effect of the Ni-Co alloy and the rare-earth compound on the electrode surface.