TiN anchored ultrafine IrCo alloy with strong electronic coupling effect as highly-efficient OER electrocatalyst for proton exchange membrane electrolyzers

Proton exchange membrane water electrolyzer (PEMWE) coupled with renewable energy is an ideal way to produce green hydrogen. However, the high load of precious metal catalysts and the requirement of catalyst durability in acidic environment restrict the large-scale application of PEM electrolyzers. Herein, an IrCo alloy electrocatalyst supported on metal titanium nitride (TiN) is synthesized, which has excellent acid oxygen evolution reaction (OER) activity and durability. The electrocatalyst exhibits a low overpotential of 246 mV@10 mA cm −2 and a higher mass activity of 0.84 A mg Ir −1 at 1.53 V in 0.5 M H 2 SO 4 . After stable operation for more than 220 h at 10 mA cm −2 , the degradation rate is negligible. When used as an anode catalyst (0.2 mg Ir cm −2 ) for the PEM electrolyzer, only 1.78 V is needed to reach 1.0 A cm −2 . The structure characterization and theoretical calculation (DFT) show that there is a strong electron coupling between TiN support and IrCo alloy. This unique effect regulates the d-band center of IrCo@TiN and optimizes the adsorption energy of the oxygen-containing intermediates, which effectively reduces the energy barrier of *O forming *OOH in the rate-determining step of OER catalytic reaction.