Co₃ O₄ /Fe_0.33 Co_0.66 P Interface Nanowire for Enhancing Water Oxidation Catalysis at High Current Density

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 Co₃ O₄ /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(CO₃ )_0.5 (OH)·0.11H₂ O (Co-CHH) nanowires with Fe(CN)₆ ^3- , followed by low-temperature phosphorization treatment. The resulting Co₃ O₄ /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, Co₃ O₄ /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 RuO₂ (446 mV). Co₃ O₄ /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 Co₃ O₄ /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 Co₃ O₄ /Fe_0.33 Co_0.66 P interface.