Synthesis and characterization of porous nanostructured Ni/PdNi electrode towards electrooxidation of borohydride

An electrochemical approach to nanostructured Ni/PdNi catalyst design using the electrodeposition process and galvanic replacement technique is presented. The procedure consisted of the electrodeposition of Ni–Zn on the Ni coating, with subsequent replacement of the zinc by palladium at open circuit in a palladium containing alkaline solution. The surface morphologies and compositions of coatings were determined by energy dispersive X-ray and scanning electron microscopy techniques. The results showed that the Ni/PdNi coatings were porous, and composed of discrete Pd nanoparticles with the crystallite size of about 58 nm. The electrocatalytic activity of Ni/PdNi electrodes towards electrooxidation of borohydride was studied using cyclic voltammetry and electrochemical impedance spectroscopy techniques. The anodic peak current density was found to be up to eight times higher on Ni/PdNi electrode for sodium borohydride compared to that for flat palladium. Therefore, the Ni/PdNi catalysts can be potential anode catalysts for the direct borohydride fuel cell.