Interconnected Network of Core–Shell CoP@CoBiPi for Efficient Water Oxidation Electrocatalysis under Near Neutral Conditions

Developing earth-abundant electrocatalysts for efficient and stable water oxidation under near neutral conditions is of great importance but still remains a key challenge. Herein, we demonstrate the development of an interconnected network of core-shell CoP@CoBiPi through anodic polarization of a CoP nanoarray in potassium borate aqueous electrolyte (KBi). This 3 D CoP@CoBiPi exhibits high catalytic activity for water oxidation at pH 9.2 and needs an overpotential (η) of only 410 mV to drive a geometrical catalytic current density of 10 mA cm^-2 , with a high turnover frequency of 819 h^-1 at an overpotential of 610 mV. Remarkably, this catalyst also demonstrates high long-term electrochemical stability with its activity being maintained for at least 27 h in KBi. This study provides us an attractive earth-abundant 3 D catalyst electrode for water-splitting devices toward efficient and stable water oxidation under benign conditions.