Promoting active species generation by sculpting Co3S4/Co(OH)2 nanotubes with rich sulfide/hydroxide interfaces for efficient oxygen evolution reaction

Nanostructured transition metal sulfides (TMSs) have attracted great attention owing to their superior electric conductivity and easy redox reaction properties in oxygen evolution reaction (OER) catalysts. However, the strong metal-metalloid bonds (M−S) and metalloid-metalloid (SS) bonds in the crystal structure of TMSs are difficult to break, which might result in the insufficient formation of electrocatalytically active metal hydroxide species on the surface and prevent the realization of their full OER potential. Herein, we demonstrate an approach by sculpting Co(OH)₂ on Co₃S₄ nanotubes (Co₃S₄/Co(OH)₂) as highly reactive and stable electrocatalysts for efficient OER. The electron transfer between cobalt and sulfur and the pre-sculpted Co(OH)₂ promote the formation of rich hydroxide active species on the surface of Co₃S₄/Co(OH)₂. The optimized Co₃S₄/Co(OH)₂–0.8 catalyst possesses excellent electrocatalytic activity for OER in an alkaline medium, with a relatively low OER overpotential of 269 mV (at 10 mA cm⁻²) and a Tafel slope of 95.2 mV dec^-1. This work provides a new sight of designing TMS electrocatalysts for practical application in efficient water splitting.