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 Ti3C2Tx MXene layers was employed by uniformly
growing embedded WS2 two-dimensional (2D) nanopetal-like
sheets through a facile solvothermal method. We exploited the interactions
between WS2 nanopetals and Ti3C2Tx nanolayers to enhance HER performance. A
much safer method was adopted to synthesize the base material, Ti3C2Tx MXene, by etching
its MAX phase through mild in situ HF formation. Consequently, WS2 nanopetals 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 WS2 and Ti3C2Tx MXene. 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 WS2 into MXene, the 5% WS2–Ti3C2Tx MXene sample exhibited
the best activity toward HER, with a low overpotential value of 66.0
mV at a current density of −10 mA cm–2 in
a 1 M KOH electrolyte and a remarkable Tafel slope of 46.7 mV·dec–1. The intercalation of 2D WS2 nanopetals
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-WS2 and Ti3C2Tx MXene realign
the active centers for HER, thereby reducing the overpotential barrier.