1T/2H MoSe2-on-MXene heterostructure as bifunctional electrocatalyst for efficient overall water splitting

Abstract Designing inexpensive yet active bifunctional electrocatalysts to directly split water is extremely desirable for the ever-broader applications of hydrogen energy. Herein, we present a cost-efficient multiphasic 1T/2H MoSe2-on-MXene nanosheets heterostructure (denote as 1T/2H MoSe2/MXene) as electrocatalyst for efficient overall water splitting. On one hand, the 1T/2H MoSe2 possesses abundant active sites providing relatively high electrocatalytic activity. On the other hand, the MXene nanosheets serve as high-conductive 2D substrates capable of promoting charge transfer ability and preventing 1T/2H MoSe2 from aggregation. Consequently, the 1T/2H MoSe2/MXene catalyst in alkaline media exhibits remarkable synergy in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity having advantage over pure 1T/2H MoSe2, MXene and 2H MoSe2/MXene counterparts. To be specific, for HER performance, the 1T/2H MoSe2/MXene reveals an overpotential (95 mV) and Tafel slope (91 mV dec−1); for OER performance, the 1T/2H MoSe2/MXene shows an overpotential (340 mV) and Tafel slope (90 mV dec−1). Particularly, when 1T/2H MoSe2/MXene serving as bifunctional electrocatalyst for overall water splitting, only 1.64 V is requested to attain a current density of 10 mA cm−2. The 1T/2H MoSe2/MXene heterostructure also exhibits good durability in overall water splitting system.