Direct O-O Coupling Promoted the Oxygen Evolution Reaction by Dual Active Sites from Ag/LaNiO3 Interfaces

Abstract

The development of highly active oxygen evolution reaction (OER) electrocatalysts is one of the most important issues for advanced water electrolysis technology with high energy efficiency. However, according to the conventional adsorbate evolution mechanism (AEM), the OER activity is theoretically limited with high overpotential by the scaling relationship in binding energies of the reaction intermediates. We propose an attractive strategy to promote OER activity by direct O-O coupling at the interfacial active sites for Ag (x) nanoparticles decorated on La1-xNiO3 perovskite electrocatalysts (Ag/LNO-x). The overpotential of the Ag/LNO-0.05 was 315 mV at a current density of 10 mA cm(geo)(-2), which was much lower than that of other Ag/LNO-x (x = 0, 0.3, and 0.5) and commercial iridium oxide (IrO2, 398 mV) electrocatalysts. The theoretical calculation revealed that the improved OER electrocatalytic activity of Ag/LNO-x originated from a change in the reaction mechanism at the interfacial active sites. At the interface, oxygen evolution via the dual-site mechanism with direct O-O coupling becomes more favorable than that via the conventional AEM. Finally, due to the formation of the interfacial active sites, the synthesized Ag/LNO-0.05 electrocatalyst showed significantly enhanced OER activity, which was 20 times higher mass activity before and 74 times after an accelerated durability test than that of the IrO2 electrocatalyst.