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.