Homologous Catalysts Based on Fe‐Doped CoP Nanoarrays for High‐Performance Full Water Splitting under Benign Conditions

The design and development of earth-abundant electrocatalysts for efficient full water splitting under mild conditions are highly desired, yet remain a challenging task. A homologous Fe-doped Co-based nanoarray incorporating complementary catalysts is shown to effect high-performance and durable water splitting in near-neutral media. Iron-doped cobalt phosphate borate nanoarray on carbon cloth (Fe-Co-Pi-Bi/CC) derived from iron-doped cobalt phosphide on CC (Fe-CoP/CC) through oxidative polarization behaves as a highly active bimetallic electrocatalyst for water oxidation with an overpotential of 382 mV to afford a catalytic current density of 10 mA cm^-2 in 0.1 m potassium borate (K-Bi, pH 9.2). Fe-CoP/CC is also highly active for the hydrogen evolution reaction, capable of driving 10 mA cm^-2 at an overpotential of only 175 mV in 0.1 m K-Bi. A two-electrode water electrolyzer incorporating Fe-Co-Pi-Bi/CC as anode and Fe-CoP/CC as cathode achieves 10 mA cm^-2 water-splitting current at a cell voltage of 1.95 V with strong long-term electrochemical durability.