资源环境科技发展态势分析平台

Abstract

The layered oxide Na_0.67CoO₂ with Na⁺ occupying trigonal prismatic sites between CoO₂ layers exhibits a remarkably high room temperature oxygen evolution reaction (OER) activity in alkaline solution. The high activity is attributed to an unusually short O–O separation that favors formation of peroxide ions by O⁻–O^– interactions followed by O₂ evolution in preference to the conventional route through surface O–OH^– species. The dependence of the onset potential on the pH of the alkaline solution was found to be consistent with the loss of H⁺ ions from the surface oxygen to provide surface O⁻ that may either be attacked by solution OH⁻ or react with another O⁻; a short O–O separation favors the latter route. The role of a strong hybridization of the O–2p and low-spin Co^III/Co^IV π-bonding d states is also important; the OER on other Co^III/Co^IV oxides is compared with that on Na_0.67CoO₂ as well as that on IrO₂.