Ir/IrOx/WO3 electrocatalysts for water splitting†

Developing high-performance electrocatalysts for water splitting in both acidic and basic electrolytes is of significance for hydrogen production. Despite the great advances achieved, efficient design and synthesis of electrocatalysts with the same chemical composition for both hydrogen and oxygen evolution in the same electrolyte is still expected. Herein, a series of Ir/IrO_x/WO₃ electrocatalysts, synthesized via electrospinning and subsequent pyrolysis, delivered high performance for both hydrogen and oxygen evolution in acidic and basic environments. Among them, Ir/IrO_x/WO₃ calcinated at 350 °C delivered the best activity for oxygen evolution through a lattice oxygen mediated pathway. Ir/IrO_x/WO₃ treated at 450 °C exhibited the highest activity for hydrogen evolution in both acidic and basic electrolytes due to the enhanced adsorption of active hydrogen species in the acidic electrolyte and promoted water dissociation in the basic electrolyte, respectively. Thereafter, coupling two electrocatalysts as the cathode and the anode delivered high performance for overall water splitting in both acidic and basic electrolytes.