Electrocatalytic behavior of the Pd-modified electrocatalyst for hydrogen evolution

The hydrogen evolution behavior of C/CoSn, C/CoSnZn and C/CoSnZn–Pd catalysts which were prepared on a graphite substrate (C) by electrochemical deposition, as well as their electrochemical properties in the KOH solutions, have been investigated by the polarization measurements, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and electrolysis techniques. C/CoSnZn catalyst was etched in caustic to leach out zinc and to produce the Raney-type, porous electrocatalytic surface for hydrogen evolution. In order to further improve the catalytic activity of the C/CoSnZn catalyst for the hydrogen evolution reaction (HER), this catalyst was modified by loading a small amount of Pd. Results showed that the modification of C/CoSnZn catalyst by deposition of a small amount of Pd can render cathode material very active in hydrogen evolution. High catalytic activity of the C/CoSnZn–Pd catalyst depends on the surface porosity, large specific surface area and well known intrinsic catalytic activity of Pd.

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► The loading of the precious metal on the catalyst was extremely low.
► The activity of Pd-modified catalyst is much higher than that of C/CoSn.
► The Pd-modified catalyst shows significantly enhanced hydrogen evolution activity.