In Situ Growth of Interfacially Nanoengineered 2D–2D WS2/Ti3C2TxMXene for the Enhanced Performance of Hydrogen Evolution Reactions

In line with current research goals involving water splitting for hydrogen production, this work aims to develop a noble-metal-free electrocatalyst for a superior hydrogen evolution reaction (HER). A single-step interfacial activation of Ti3C2TxMXene layers was employed by uniformly growing embedded WS2two-dimensional (2D) nanopetal-like sheets through a facile solvothermal method. We exploited the interactions between WS2nanopetals and Ti3C2Txnanolayers to enhance HER performance. A much safer method was adopted to synthesize the base material, Ti3C2TxMXene, by etching its MAX phase through mild in situ HF formation. Consequently, WS2nanopetals were grown between the MXene layers and on edges in a one-step solvothermal method, resulting in a 2D–2D nanocomposite with enhanced interactions between WS2and Ti3C2TxMXene. The resulting 2D–2D nanocomposite was thoroughly characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses before being utilized as working electrodes for HER application. Among various loadings of WS2into MXene, the 5% WS2–Ti3C2TxMXene sample exhibited the best activity toward HER, with a low overpotential value of 66.0 mV at a current density of −10 mA cm–2in a 1 M KOH electrolyte and a remarkable Tafel slope of 46.7 mV·dec–1. The intercalation of 2D WS2nanopetals enhances active sites for hydrogen adsorption, promotes charge transfer, and helps attain an electrochemical stability of 50 h, boosting HER reduction potential. Furthermore, theoretical calculations confirmed that 2D–2D interactions between 1T/2H-WS2and Ti3C2TxMXene realign the active centers for HER, thereby reducing the overpotential barrier.