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

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 Mo2TiC2Tx MXene, which was then composited with MoS2 and CoS2 to prepare defect-rich MoS2/CoS2@Mo2TiC2Tx composite by a hydrothermal method. MoS2/CoS2 provides a large number of active sites for electrocatalysis, while Mo2TiC2Tx 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 Mo2TiC2Tx MXene. Consequently, MoS2/CoS2-2@Mo2TiC2Tx exhibits an excellent HER performance. When the current density reaches 10 mA cm−2, the optimal MoS2/CoS2-2@Mo2TiC2Tx 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.