In-situ synthesis of Ag-Pi oxygen-evolving catalyst in phosphate environment for water splitting

An efficient Ag-P_i oxygen-evolving catalyst was fabricated in situ in a phosphate electrolyte solution (pH 12.4). The catalyst approaches an amorphous structure, unlike the reported Ag-based oxygen-evolving catalysts. The catalytic activity for water oxidation of the Ag-P_i catalyst is 11.1 μmol h^?1 cm^?2 and it has a modest oxygen-evolution overpotential of 457.0 mV at 1 mA cm^?2 in 0.1 M K₃PO₄ electrolyte. The effects of different electrolytes on the formation of the Ag-P_i catalyst were investigated. The active component of the Ag-P_i oxygen-evolving catalyst as a water-splitting catalyst is the AgO phase as determined by X-ray diffractometry and X-ray photoelectron spectroscopy analysis. A Ag-P_i mechanism that includes the Ag(I) and Ag(III) cycles is proposed to explain the electrocatalytic oxygen evolution.