Edge-oriented, high-percentage 1T′-phase MoS2 nanosheets stabilize Ti3C2 MXene for efficient electrocatalytic hydrogen evolution

Abundant electrochemical active sites, high electronic conductivity as well as stable structure and electrochemical activity are indispensable but usually incompatible to the ideal electrocatalysts for hydrogen evolution reaction (HER). Herein, an efficient and stable MoS2-Ti3C2 MXene electrocatalyst is synthesized using a delicately designed one-step hydrothermal method, in which the few-layers thick, edge-oriented, high-percentage 1T′-phase (∼ 85.0 %) MoS2 nanosheets are well grown on the cation-modified Ti3C2 MXene and stabilize Ti3C2 MXene against spontaneous oxidation caused by dissolved-oxygen. The structure and phase engineering of MoS2 as well as the fully surface-shielding Ti3C2 MXene endow the as-synthesized MoS2-Ti3C2 MXene electrocatalyst with a wealth of accessible active sites and high electrical conductivity for HER together with excellent structure stability. Consequently, the as-synthesized MoS2-Ti3C2 MXene exhibits remarkable electrocatalytic HER performance in acidic medium with a low overpotential of 98 mV at 10 mA cm-2, a depressed Tafel slope of 45 mV dec-1 and a low electrochemical resistance.