In situ surface derivation of an Fe–Co–Bi layer on an Fe-doped Co3O4 nanoarray for efficient water oxidation electrocatalysis under near-neutral conditions

Abstract

Developing high-performance water oxidation electrocatalysts working under mild conditions is highly desirable, but still remains challenging. In this communication, we report the in situ surface derivation of an Fe–Co–Bi layer (4–7 nm in thickness) on an Fe-doped Co₃O₄ nanowire array supported on carbon cloth (Fe–Co₃O₄/CC). As a 3D catalyst electrode for water oxidation, such a core–shell Fe–Co₃O₄@Fe–Co–Bi nanoarray (Fe–Co₃O₄@Fe–Co–Bi/CC) demonstrates superior activity over that of a Co₃O₄-derived nanoarray catalyst, with the need of an overpotential of 420 mV to drive a geometrical catalytic current density of 10 mA cm⁻² in 0.1 M potassium borate (pH = 9.2). Notably, this catalyst also shows good long-term stability with high turnover frequencies.