A supercritical growth strategy for 1T/2H mixed-phase MoS2 nanosheets of high activity and stability

Abstract

Molybdenum disulfide (MoS2) with the hydrogen adsorption energy similar to Pt is an ideal catalyst for the hydrogen evolution reaction (HER). However, its hydrogen evolution performance is seriously restricted by the limited active sites within the basal plane, especially for the 2H phase. Herein, a supercritical growth method is developed to directly grow MoS2 nanosheets on carbon cloth (CC) in acidic aqueous solution. SEM, TEM, XPS and Raman characterization proved the supercritical heterogeneous nucleation and growth of MoS2 nanosheets on CC. The nanosheets have the 1T/2H mixed-phase structure with the 1T phase content of 88%. The interlayer of MoS2 nanosheets is expanded and distorted due to the insertion of large cations TMA+, promoting the formation of 1T phase. The electrochemical test confirmed that 1T/2H–MoS2@CC exhibited superior HER performance in both alkaline and acidic solution compared to the previous reports, showing a small overpotential of 135 mV@10 mA cm−2 and 114 mV@10 mA cm−2 as well as a low Tafel slope of 84.5mV/dec and 52.8 mV/dec in alkaline and acidic solution, respectively. Moreover, 1T/2H–MoS2@CC exhibits high stability in alkaline solution without significant degradation after 100 h galvanostatic test at 100 mA cm−2. Considering the extremely small amount of raw material consumption, our work provides a practical route for a low-cost MoS2 nanosheets and lowers the industrial threshold for the hydrogen production by water electrolysis.