Defect-rich MoS2/CoS2 on Mo2TiC2Tx MXene as an efficient catalyst for hydrogen evolution reaction in acidic media

Abstract

Electrocatalytic hydrogen production is an effective way to produce hydrogen energy, and the key is to find inexpensive and effective catalysts. Loading transition metal sulfides onto two-dimensional transition metal carbide (MXene) is an effective method to prepare cheap and high-performance hydrogen evolution reaction (HER) catalysts. In this study, Mo₂TiAlC₂ was etched with hydrofluoric acid to prepare Mo₂TiC₂T_x MXene, which was then composited with MoS₂ and CoS₂ to prepare defect-rich MoS₂/CoS₂@Mo₂TiC₂T_x composite by a hydrothermal method. MoS₂/CoS₂ provides a large number of active sites for electrocatalysis, while Mo₂TiC₂T_x MXene as a carrier not only provides nucleation and growth sites for MoS₂/CoS₂, but also increases the rate of electron transfer in HER process, which achieves good synergy between MoS₂/CoS₂ and Mo₂TiC₂T_x MXene. Consequently, MoS₂/CoS₂-2@Mo₂TiC₂T_x exhibits an excellent HER performance. When the current density reaches 10 mA cm⁻², the optimal MoS₂/CoS₂-2@Mo₂TiC₂T_x catalyst only requires an overpotential of 80 mV, and exhibits good cycling stability and durability. This work gives a new idea for the preparation of efficient HER catalysts using non-precious metal composites to replace the precious Pt/C.