Achieving asymmetric redox chemistry for oxygen evolution reaction through strong metal-support interactions

Water electrolysis poses a significant challenge for balancing catalytic activity and stability of oxygen evolution reaction (OER) electrocatalysts. In this study, we address this challenge by constructing asymmetric redox chemistry through elaborate surface OO-Ru-OH and bulk Ru-O-Ni/Fe coordination moieties within single-atom Ru-decorated defective NiFe LDH nanosheets (Ru@d-NiFe LDH) in conjunction with strong metal-support interactions (SMSI). Rigorous spectroscopic characterization and theoretical calculations indicate that single-atom Ru can delocalize the O 2p electrons on the surface and optimize d-electron configurations of metal atoms in bulk through SMSI. The 18O isotope labeling experiment based on operando differential electrochemical mass spectrometry (DEMS), chemical probe experiments, and theoretical calculations confirm the encouraged surface lattice oxygen, stabilized bulk lattice oxygen, and enhanced adsorption of oxygen-containing intermediates for bulk metals in Ru@d-NiFe LDH, leading to asymmetric redox chemistry for OER. The Ru@d-NiFe LDH electrocatalyst exhibits exceptional performance with an overpotential of 230 mV to achieve 10 mA cm−2 and maintains high robustness under industrial current density. This approach for achieving asymmetric redox chemistry through SMSI presents a new avenue for developing high-performance electrocatalysts and instills confidence in its industrial applicability.