Interfacial engineering for design of novel 2D cobalt sulfide-Mxene heterostructured catalyst toward alkaline water splitting

In this work, we used an interfacial engineering method to investigate a novel hybrid of two-dimensional cobalt sulfide-Mxene (2D CoS-Mo2TiC2) heterostructure supported by a three-dimensional foam substrate. The modification electronic properties caused by unique interfacial interactions resulted in a significant increase in the number of electroactive sites and charge transfer ability, thereby accelerating kinetics of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium. The catalyst required overpotential of 248.2 and 310 mV at a current response of 50 mA cm−2 for HER and OER, respectively, along with a remarkable stability. In addition, a two-electrode electrolyzer derived from the developed 2D CoS-Mo2TiC2 catalyst showed a cell voltage of 1.74 V at 10 mA cm−2 and a good stability during 25 h continuous operation. The achieved results were associated to the formation of a unique interfacial heterostructure with the strong interaction between two material phases, which effectively modified electronic structure and surface chemistry, thereby leading to the enhancement of catalytic performance. The study offered a potential route to synthesize new catalyst for green hydrogen production via water splitting.