VS2 Nanoflowers Supported on Ti3C2 MXene as Electrocatalyst for the Hydrogen Evolution Reaction

Under the threat of the two major dilemmas of energy scarcity and environmental degradation, the development of sustainable, clean, and efficient energy sources has become increasingly urgent. In recent years, electrocatalytic hydrogen evolution reaction (HER) has become a promising method for the preparation of energy sources for sustainable hydrogen production. However, the monolithic nature of the active site/active phase of metallic transition metal disulfides (MTMDs) limits the performance of HER to that of commercial Pt/C catalysts. Herein, we report the hydrothermal growth of VS2/Ti3C2 heterogeneous structure on MXene substrates for the first time. The VS2/Ti3C2 heterogeneous structure exhibits extremely high catalytic activity and electrochemical durability. Exhibiting an overpotential of only 33 mV and a Tafel slope of 25.93 mV dec–1 in 0.5 M H2SO4 acidic electrolyte, the catalysts showed excellent durability over 24 h and near 100% Faraday efficiency. Meanwhile, the formation of heterogeneous structure was also demonstrated by both X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) data. Theoretical studies confirmed that the successful construction of Ti–S bonds in VS2/Ti3C2 heterogeneous structure accelerates the charge transfer rate, which modifies the electrical properties of VS2 nanoflowers and the hydrogen adsorption properties at the Ti-edge and the S-edge. This work accelerated the charge transfer rate of the electrocatalyst through the formation of a heterogeneous structure between VS2 and Ti3C2, providing a strategy for highly efficient electrocatalytic hydrogen evolution reaction.