Engineered Co-O-Mo active centers for enhanced water oxidation via lattice oxygen mechanism

Heterostructured transition-metal compounds show great potential in the oxygen evolution reaction (OER), but the reaction mechanism induced by the surface reconstruction remains unclear. Herein, we develop a kind of Co-O-Mo active center in Co oxyhydroxide (MoCoOOH) via in situ reconstruction, which exhibits an overpotential of 275 mV at 10 mA cm−2 in alkaline conditions, as well as negligible deactivation after durability operation driven by a solar cell. The operando tests reveal that Mo accelerates the reconstruction from Co-Se-Mo to Co-O-Mo in MoCoOOH, which triggers the lattice oxygen activation for enhanced intrinsic OER activity. Theoretical calculations demonstrate that the Mo atoms can optimize the d-orbital energy level of Co metal atoms, adsorption-desorption oxygenated intermediates, and the rate-determining step barrier. This work gives deep insights into the oxygen-involved mechanism in the reconstructed phase and inspires the rational design of high-activity electrocatalysts in multi-electron reactions.