Bifunctional WS2@Co3S4 core-shell nanowire arrays for efficient water splitting

WS2 nanosheets (NSs) grow on Co3S4 nanowires (NWs) and form a heterostructure on carbon cloth (CC) via in situ deposition and ion exchange. This three-dimensional (3D) core shell architecture benefits mass diffusion and electron transfer at the heterojunction interface, and features more active sites and open structure available to the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The WS2@Co3S4 NW/CC shows a superior HER and OER activity in an alkaline solution with only an overpotential of 82 mV for HER and 280 mV for OER to deliver a current density of 10 mA cm(-2). The corresponding Tafel slope of HER and OER is 45 and 52 mV dec(-1), respectively. Moreover, the WS2@Co3S4 NW/CC can maintain HER/OER activity without significant loss for 24 h at the current density of 10 mA cm(-2). The superior bifunctional catalytic performance of WS2@Co3S4 NW/CC can substantially expedite its application in overall water splitting, which can deliver a current density of 100 mA cm(-2) with only cell voltage of 1.56 V in a two-electrode electrolytic cell. This work may open up a novel avenue to design and prepare highly cost-effective catalysts for energy storage and conversion. (C)& nbsp;2021 Published by Elsevier Ltd.