Interfacial Electron Accumulation of Ir-Co3o4 Toward Efficient Acidic Oxygen Evolution Reaction

Abstract

Acidic oxygen evolution reaction (OER) is a major limitation of practical hydrogen production from water electrolysis. Here, we developed an interfacial electron modulation strategy on the basis of Ir-Co3O4 hybrids to build an anomaly OH-rich catalyst-electrolyte layer for efficient OER. Our theoretical studies predict that electron accumulation preferentially occurs on O near Ir sites, which is confirmed via X-ray based and advanced electron microscopy characterization. The accumulated interfacial electron density is up to 20.0 e/Å2 according to the quantification results of integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM) imaging. In-situ Raman results show that the accumulated electron at the interface can promote dissociation of the adsorbed water, and thus generate an OH-rich catalyst-electrolyte layer. The designed Ir-Co3O4 catalyst exhibits a low overpotential of 200 mV at 10 mA/cm2 in normal three-electrode testing, as well as a high stability for 160 h at 350 mA/cm2 in a proton-exchange membrane electrolyzer. We believed that this developed electron modulation strategy is highly meaningful for rational design of efficient OER catalyst.

Keywords: metal oxides interface, interfacial water, Electrocatalysts, iDPC-STEM, heterogeneous catalysts