Synergistic effect of two actions sites on cobalt oxides towards electrochemical water-oxidation

Developing effective ways to promote the sluggish oxygen evolution reaction (OER) still remains a great challenge due to the interdependence multiple steps procedure. Herein, we design a two action sites strategy to break interdependence restriction to reduce the calculative overpotential. Density functional theory demonstrated that the introduced oxygen vacancies could accelerate the oxidation of H2O by induced an extra reaction step, corresponding deprotonation of H2O* decomposed into two separated reaction steps: H2O* ↔ (HO + H)* and (HO + H)*↔ HO* + H+ + e-. Meanwhile, experimental observations confirm that two action sites promote the Vo-CoOOH OER performance including a lower onset potential, a lower Tafel slope and an incremental Turnover frequency (TOF) from 0.01 to 0.04 s−1. Through this work, a viable design principle for, but not limited to, CoOOH OER catalyst is proposed: injected hole can activate the synergistic catalytic effect of two actions sites to accelerate the water oxidation.