Electrodeposition of Pd catalyst layer on graphite rod electrodes for direct formic acid oxidation

► A new method for electrodepositing Pd catalyst layer on graphite rods was proposed. ► The Pd catalyst layer showed an island-like morphology and a multi-layer structure. ► Anionic sulfonic groups of Nafion had electrostatic repulsion to [PdCl4]2− anions. ► Decreased electrodeposition overpotentials led to the formation of Pd islands. ► Predominant Pd (111) made the catalyst highly active toward formic acid oxidation.