Co3 O4 Nanowire Arrays toward Superior Water Oxidation Electrocatalysis in Alkaline Media by Surface Amorphization.

It is highly desirable to develop a simple, fast and straightforward method to boost the alkaline water oxidation of metal oxide catalysts. In this communication, we report our recent finding that the generation of amorphous Co-borate layer on Co3 O4 nanowire arrays supported on Ti mesh (Co3 O4 @Co-Bi NA/TM) leads to significantly boosted OER activity. The as-prepared Co3 O4 @Co-Bi NA/TM demands overpotential of 304 mV to drive a geometrical current density of 20 mA cm-2 in 1.0 M KOH, which is 109 mV less than that for Co3 O4 NA/TM, with its catalytic activity being preserved for at least 20 h. It suggests that the existence of amorphous Co-Bi layer promotes more CoOx (OH)y generation on Co3 O4 surface.