Interfacial Engineering of Z-Scheme-Based 2D/1D -WS₂/TiO₂ Heterostructures: Enhanced Hydrogen Evolution Reaction and Fabrication of Facile Photoelectrochemical Device

Hydrogen, essential for clean and sustainable energy solutions, encounters significant challenges in electrochemical water splitting. This study introduces a Z-Scheme WS2/TiO2 heterostructure synthesized via a hydrothermal method, aimed at enhancing hydrogen evolution reaction (HER) performance through interface engineering. Comprehensive interfacial investigations were conducted by using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and UV–vis spectroscopy. XPS analysis revealed peak shifts in the heterostructure, indicative of electronic modifications at the interface. These shifts enhance active site availability, and charge transfer kinetics also corroborated its UPS and UV–vis studies. The establishment of an intimate interface fostering a Z-scheme charge transfer mechanism has been reported. A lower work function of 4.2 eV suggests improved charge transfer at the interface. Furthermore, the development of an internal electric field to achieve Fermi level equilibrium also led to improved HER performance of the Z-scheme-based heterostructure. The prepared heterostructure demonstrated enhanced HER with a lower onset potential (−0.04 V in light and −0.05 V in dark) as compared to pristine WS2 and a lower charge transfer resistance (36.4 Ω in light and 51.2 Ω in dark), highlighting a promising approach for constructing efficient photoelectrochemical device. The study’s insights into strain-induced effects further underscore the potential of the WS2/TiO2 heterostructure for sustainable energy applications. This result paves the way for constructing the facile and efficient method for generating a photoelectrochemical device with solar-to-hydrogen (STH) efficiency equal to 1.16% determined using the water displacement method.