Strong electronic coupling between single Ru atoms and cobalt-vanadium layered double hydroxide harness efficient water splitting

Abstract

Atomic coordination modulation and electronic structure engineering are appealing routes to develop versatile electrocatalysts targeting high-performance water electrolysis. Herein, atomically dispersed Ru sites are successfully anchored on the surface of CoV layered double hydroxide (LDH), affording a vertically aligned and interconnected nanosheet array architecture. Benefitting from the strong electronic coupling, fast charge transfer capability and well-defined morphology of as-prepared catalyst, ultralow overpotentials for hydrogen evolution reaction (HER, eta 10 = 28 mV) and oxygen evolution reaction (OER, eta 25 = 263 mV) are required. The two-electrode configuration cell only requires a cell voltage of 1.52 V to reach 10 mA cm-2, which is lower than that of commercialized Pt/C||RuO2 couple. Synchrotron X-ray absorption spectroscopy studies in combination with density functional theory calculations reveal that the strong electronic coupling between monatomic Ru with CoV LDH induces spatial charge redistribution and a distorted coordination environment around V atoms, thereby accelerating the hydrogen release for HER and reducing the rate-determining step (O* -> OOH*) free energy for OER.