Ni/Cu Regulating Nitrogen-Doped Porous Carbon as Electrocatalyst for Oxygen Reduction Reaction

Transition metal and nitrogen co-doped carbon materials have been widely investigated as promising electrocatalysts for oxygen reduction reaction (ORR). Incorporating two different metals in N-doped carbon may synergistically improve the catalytic activity. Herein, Ni/Cu incorporated N-doped porous carbon materials (Ni1-xCux-N-C) with different Ni/Cu ratios were prepared by a direct carbonization of the metal-organic complexes which were obtained via a NaOH-mediated organometallic reaction of metal ions and benzimidazole. It is found that the Ni/Cu ratio significantly alters the Ni1-xCux particle sizes, the surface morphology, the specific surface area, and the pore structure of the catalysts, eventually affecting the ORR activities. Ni0.7Cu0.3-N-C exhibits the best ORR activity among the studied Ni1-xCux-N-C catalysts with a half-wave potential of 0.783 V and a limiting current density of 4.85 mA cm(-2) in alkaline medium. Density functional theory calculations confirm that the synergistic effect of bimetallic Ni/Cu can optimize the adsorption/desorption features and promote the ORR catalytic activities.