An amorphous Co-carbonate-hydroxide nanowire array for efficient and durable oxygen evolution reaction in carbonate electrolytes

The development of earth-abundant catalysts toward high-efficient and durable oxygen evolution reaction (OER) electrocatalysis in the carbonate electrolyte is in great demand but remains a huge challenge. In this communication, we describe the development of a Co-carbonate-hydroxide nanowire array on nickel foam (CoCH/NF) via in situ electrochemical conversion of the Co(CO₃)_0.5(OH)·0.11H₂O nanowire array. When utilized as a 3D catalyst electrode for the OER in 1.0 M KHCO₃ (pH: 8.3), as-formed CoCH/NF demands overpotential of only 332 mV to drive a geometrical catalytic current density of 10 mA cm^-2, with its catalytic activity being maintained for at least 130 h. Impressively, it also demonstrates a high turnover frequency value of 0.22 mol O₂ s^-1 at an overpotential of 500 mV.