Electron Irradiation Induces the Conversion from 2H-WSe₂ to 1T-WSe₂ and Promotes the Performance of Electrocatalytic Hydrogen Evolution

Hydrogen (H₂) is an environment-friendly clean energy. In recent years, novel hydrogen evolution electrocatalysts have attracted extensive attention in the scientific community. In this work, the conversion of 2H phase tungsten selenide (2H-WSe₂) into 1T phase tungsten selenide (1T-WSe₂) was induced by 1 MeV electron irradiation to improve its electrocatalytic performance. When the irradiation fluence is 5 × 10¹⁴ e/cm², the minimum initial overpotential of WSe₂ is 101 mV lower than the initial overpotential of WSe₂ without irradiation. This method has the characteristics for a simple process and mass production. At the same time, the atomic structure of WSe₂ was characterized and the 1T properties of WSe₂ were confirmed. The experimental results show that 1 MeV electron irradiates WSe₂ to produce Se vacancies on the base surface to form 1T-WSe₂, which is the main reason for improving its performance. This effective and feasible electron irradiation method provides a new strategy for the controllable acquisition of 1T-WSe₂ and a new method for other similar materials to introduce the ideal 1T phase.