Strongly coupling of Co9S8/Zn-Co-S heterostructures rooted in carbon nanocages towards efficient oxygen evolution reaction

Abstract

The design of efficient and nonprecious electrocatalysts towards oxygen evolution reaction (OER) is extremely essential for a wide range of renewable energy technologies but remains a grand challenge. Herein, a novel hybrid composite constructed from Co9S8/Co-doped ZnS (Zn0.8Co0.2S) nanorods with the atomic-level coupled nanointerface rooted in porous carbon polyhedra (Co9S8/Zn0.8Co0.2S@C) have been fabricated and investigated as a highly efficient electrocatalyst for OER. The composite catalyst can afford a current density of 10 mA cm−2 at a low overpotential of only 292 mV and a small Tafel slope of ∼52 mV decade−1, which are superior to the state-of-the-art IrO2/C and most reported Co-based catalysts. Experimental and computational studies reveal an electronic coupling between Co9S8 and Zn0.8Co0.2S that can facilitate the electron injection from the electrode and transport to the active site, and thus generates a favorable local coordination environment and greatly enhances the OER process.