Ni nanoparticles anchoring on vacuum treated Mo₂TiC₂T_x MXene for enhanced hydrogen evolution activity

MXenes with metal nanoparticles (NPs) immobilized on their surface are greatly desired for high-performance electrocatalysts, while the homogeneous nucleation and growth of NPs are still challenging. Herein, a new method has been proposed for uniformly anchoring Ni NPs on the altered surficial MXene. The pre-vacuum treatment on Mo2TiC2Tx (oMX) not only removes the surficial terminal groups but also induces surface oxidation defects. Meanwhile, the nucleation and growth behaviors of Ni NPs on the oMX are altered in the hydrothermal reaction, which results in a grain-size reduction of more than 50% as well as homogeneous coverage. Eventually, the oxidized surface contributes a strong coupling between oMX and Ni NPs via Ni-O binging, which endows the Ni@oMX hybrid with the lowest overpotential and high durability over 75 h in 1 M KOH solution for electrocatalytic hydrogen evolution reaction (HER).