Oxygen Evolution on in Situ Selective Formation of AgO: Plane Is the Key Factor

In this work, a method for synthesizing AgO exposed with different planes by electrodeposition using an unbuffered solution and a complexing agent as an electrolyte was first proposed. The experimental results indicate that the oxygen evolution activity of AgO crystal exhibits very obvious facet-dependent properties. AgO crystals with mainly {1̅11} exposed faces yield a superior catalytic activity over those with mainly {2̅02} exposed faces under electrochemical water oxidation conditions, which agrees with the theoretical calculations. The AgO film with dominant {1̅11} facets has a modest overpotential of 418 mV and its catalytic performance is demonstrated by long-term electrolysis at 2.03 V versus a reversible hydrogen electrode in a near-neutral potassium phosphate solution. A stable current density of 3.7 mA cm–2 persists for at least 6 h, and a Faradaic efficiency of 93% is obtained, which is much better than other Ag-based electrodes, especially current densities.