Amorphous Irmoox Electrocatalyst with Oxygen Vacancy for Highly Efficient Water Splitting in Acid

Abstract

Although acidic proton exchange membrane water electrolyzers (PEMWEs) possess great potentials in cost-efficient hydrogen production, the acidic oxygen evolution reaction (OER) kinetics is dramatically more sluggish than that in alkaline, causing inferior activity and stability. Herein, we successfully prepared the amorphous IrMoOx with abundant oxygen vacancies give superb bifunctional catalytic activity and durability in both hydrogen evolution reaction (HER) and OER in acidic media, accompanied with smaller overpotentials (27 and 238 mV) for the current density of 10 mA cm-2. Theoretical calculations uncovered the existence of the special IrO4 planar structure within the amorphous IrMoOx and illustrated that the introduced Mo as well as the rich oxygen vacancies give rise to the optimized p, d-band of metal species for better OER performance compared with IrO2. Furthermore, the IrMoOx || IrMoOx PEMWEs were shown to deliver the current density of 10 mV cm-2 at 1.55 V, superior to the commercial Pt/C || IrO2 (1.76 V for 10 mA cm-2).

Keywords: Amorphous structure, oxygen evolution reaction, water splitting