CoS 2 /MoS 2 Hollow Heterostructure as High‐efficiency Bifunctional Electrocatalyst for Overall Water Splitting

Abstract Developing high‐efficiency bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to realize low‐cost water splitting is the premise for large‐scale production of hydrogen. The catalytic activity of an electrocatalysts greatly depends on its composition and structure. In this work, we report the preparation of hollow CoS 2 /MoS 2 heterostructure using ZIF‐67 as the precursor. The ratio of Co and Mo are optimized to maximize the synergy of CoS 2 and MoS 2 , due to their specific catalytic activity for OER and HER. The optimized CoS 2 /MoS 2 exhibits good bifunctional catalytic activity in view of its low overpotentials for HER (170 mV) and OER (270 mV), as well as small cell voltage of 1.66 V for overall water splitting. This work provides a facile strategy to controllable fabrication of efficient bifunctional electrocatalysts for renewable energy applications.