Preparation of Pd/ZnO/Ni hierarchical porous array film with enhanced electrocatalytic activity for methanol oxidation

In this study, we successfully synthesized a Pd/ZnO/Ni hierarchical porous array-film catalyst by electrodeposition and magnetron sputtering with the assistance of the monodisperse colloidal sphere template. Structural characterisation indicated that a layer of Pd nanoparticles was uniformly grown on the ZnO/Ni ordered bowl-like micro/nano array film. Electrochemical measurements in alkaline solution demonstrated that the as-grown array film had outstanding electrocatalytic activity for methanol oxidation. The specific activity of the Pd/ZnO/Ni porous array film was up to 130.1 mA cm(-2). The corresponding mass activity (812.7 mA mg(-1)) was 6 times higher than that of commercial Pd/C catalyst (134.8 mA mg(-1)), and the stability was also much better than the commercial one. These excellent electrochemical properties can be attributed to the unique hierarchical porous structure, which offers a high specific surface area for the methanol reaction, and ZnO intermediate layer, which effectively removes the poisoning species from the Pd sites through the strong oxidative hydroxyl radicals. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.