Programming ORR Activity of Ni/NiOx@Pd Electrocatalysts via Controlling Depth of Surface-Decorated Atomic Pt Clusters

Carbon nanotube supported ternary metallic nanocatalysts (NCs) comprising Ni-core -Pd-shell structure and Pt atomic scale clusters in shell (namely, Ni@Pd/Pt) are synthesized by using wet chemical reduction method with reaction time control. Effects of Pt4+ adsorption time and Pt/Pd composition ratios on atomic structure with respect to electrochemical performances of experimental NCs are systematically investigated. By cross-referencing results of high-resolution transmission electron microscopy, X-ray diffraction, X-ray absorption, density functional theoretical calculations, and electrochemical analysis, we demonstrate that oxygen reduction reaction (ORR) activity is dominated