Ir atomic engineering enabling CuO nanowires for enhanced and durable alkaline oxygen evolution

Abstract

Heteroatom doping is a promising strategy for designing cost-effective and stable electrocatalysts toward the oxygen evolution reaction (OER), but the enhancement mechanism remains unclear. Herein, atomic Ir-O-Cu and Ir-O-Ir motifs are engineered into CuO nanowires via cation exchange and dehydration to elucidate the OER mechanism. Systematic characterizations confirm the atomic dispersion of Ir within the CuO lattice and the electron transfer from Ir to CuO while preserving the host structure. The as-prepared single-atom Ir-doped CuO (Ir_SA-CuO), featuring predominant Cu-O-Ir motifs and coexisting Ir-O-Ir motifs, achieves a low OER overpotential of 204 mV at 10 mA cm⁻² in 1 M KOH, coupled with a 69-fold higher mass activity than commercial IrO₂. Furthermore, the Ir_SA-CuO maintains long-term stability for 300 h at 200 mA cm⁻² with minimal overpotential alteration and an additional 120 h at 500 mA cm⁻² with overpotential increased by 15 mV. In situ Raman spectroscopy reveals that the Ir-O-Ir motifs suppress Cu^II oxidation to Cu^III by delaying the onset potential, enhancing the structural stability during OER. Density functional theory calculations demonstrate the Cu-O-Ir motifs lower the adsorption energy of bridged *O via asymmetric bonding, accelerating *OOH formation in the rate-determining step. This work presents a heteroatom engineering strategy to balance electrocatalytic activity and durability, providing a blueprint for industrial electrocatalyst design.