Ultrarapid in Situ Synthesis of Cu₂S Nanosheet Arrays on Copper Foam with Room-Temperature-Active Iodine Plasma for Efficient and Cost-Effective Oxygen Evolution

Developing simple and cost-effective methods for the rapid synthesis of oxygen evolution reaction (OER) electrocatalysts from earth-abundant elements is a highly desired yet challenging task. Herein we report a two-step strategy based on the use of a room-temperature- and atmospheric-pressure-active iodine DBD plasma and an anion exchange reaction for the in situ generation of 3D Cu 2 S nanosheet arrays on Cu foam (Cu 2 S/CF). Owing to the advantages of this plasma-based approach, and the extremely rapid anion exchange reaction between the generated CuI and S 2–, synthesis of the Cu 2 S/CF OER catalyst can be accomplished within 6 min. The porous 3D catalyst exhibited prominent electrocatalytic activity and persistent stability (>10 h) for OER with an overpotential of 336 mV to drive a geometrical current density of 20 mA cm –2 in 1.0 M KOH, comparable to the performance of a noble-metal IrO 2 /CF electrode.