Interface Charge Transfer of Heteroatom Boron Doping Cobalt and Cobalt Nitride for Boosting Water Oxidation
Fuzhan Song, Xiang Ding, Yangyang Wan, Tong Zhang, Guogeng Yin, Jesse B. Brown, Yi Rao
Abstract
Designing high-performance transition-metal electrocatalysts with controlled active heterointerfacial sites for catalyzing the electrochemical oxygen evolution reaction (OER) is very desirable but remains a great challenge. Here, a facile strategy for the synthesis of transition-metal nitride-based interfacial electrocatalysts boron-doped cobalt/cobalt nitride (B–Co/Co 2 N) is demonstrated with optimal heterointerfaces between Co and Co 2 N electrocatalysts by introducing boron as a dopant to the former. Benefiting from the unique electronegativity of B, the obtained B–Co/Co 2 N electrocatalysts show excellent OER performance with overpotential inputs of as low as 262 and 310 mV for 10 and 100 mA cm –2, which are 1.4 and 6.6 times higher than those of Co/Co 2 N with the same potential input, respectively. The experimental and theoretical results demonstrate the role of the B dopant in inducing charge redistribution of Co active sites in the Co/Co 2 N interfacial region, which results in a downshift of the Co 3d band center, the optimal oxidation state of active sites for *OOH formation, and lower energy barriers. Furthermore, the assembled electrolyzer can steadily produce an industrial-grade current density of 1000 mA cm –2 at a cell voltage input of only 1.81 V for at least 100 h with a Faradaic efficiency near 100%. This study provides a promising strategy for heteroatom-doped interfacial electrocatalysts with high performance for energy and environmental applications.