Co3O4/Fe0.33Co0.66P Interface Nanowire for Enhancing Water Oxidation Catalysis at High Current Density

Abstract Designing well‐defined nanointerfaces is of prime importance to enhance the activity of nanoelectrocatalysts for different catalytic reactions. However, studies on non‐noble‐metal‐interface electrocatalysts with extremely high activity and superior stability at high current density still remains a great challenge. Herein, a class of Co 3 O 4 /Fe 0.33 Co 0.66 P interface nanowires is rationally designed for boosting oxygen evolution reaction (OER) catalysis at high current density by partial chemical etching of Co(CO 3 ) 0.5 (OH)·0.11H 2 O (Co‐CHH) nanowires with Fe(CN) 6 3− , followed by low‐temperature phosphorization treatment. The resulting Co 3 O 4 /Fe 0.33 Co 0.66 P interface nanowires exhibit very high OER catalytic performance with an overpotential of only 215 mV at a current density of 50 mA cm −2 and a Tafel slope of 59.8 mV dec −1 in 1.0 m KOH. In particular, Co 3 O 4 /Fe 0.33 Co 0.66 P exhibits an obvious advantage in enhancing oxygen evolution at high current density by showing an overpotential of merely 291 mV at 800 mA cm −2 , much lower than that of RuO 2 (446 mV). Co 3 O 4 /Fe 0.33 Co 0.66 P is remarkably stable for the OER with negligible current loss under overpotentials of 200 and 240 mV for 150 h. Theoretical calculations reveal that Co 3 O 4 /Fe 0.33 Co 0.66 P is more favorable for the OER since the electrochemical catalytic oxygen evolution barrier is optimally lowered by the active Co‐ and O‐sites from the Co 3 O 4 /Fe 0.33 Co 0.66 P interface.