Enhanced Electrochemical Performance and Charge-Transfer Dynamics of 2D MoS₂/WO₃ Nanocomposites for Futuristic Energy Applications

Abstract

The hybrid structures of transition-metal dichalcogenides and oxides show enhanced properties by incorporating the qualities of two pristine materials into a single one. In view of this, the present work focuses on synthesizing a series of MoS 2 /WO 3 nanocomposites wherein the molar ratio of MoS 2 to WO 3 was gradually varied to achieve the optimized properties for photovoltaic applications. The samples were analyzed for structural, optical, morphological, microstructural, electrokinetic, electrical, and electrochemical properties. Integrating the properties of MoS 2 and WO 3 provided enhanced properties in the form of wider absorbance range, optimized band gap, better colloidal stability, and increased charge-carrier mobility. The as-synthesized nanocomposites showed the absorbance in UV and visible regions with the band gap varying from 1.3 to 2.66 eV. The zeta potential measurement showed high colloidal stability of some of the nanocomposites with values < −30 mV. Hall effect study of MoS 2 /WO 3 nanocomposites revealed the enhancement in electrical properties, and the mobility is found to be of the order of 880 m 2 /(V s). The redox process was also more prominent for nanocomposite materials as well as enhanced diffusive behavior as analyzed by cyclic voltammetry. The presence of Warburg diffusion along with high-exchange current density was also observed in few samples as analyzed by potentio electrochemical impedance spectroscopy with the highest value of 336 μA. The present study reveals that the catalytic, optical, electrical, and electrochemical properties of MoS 2 /WO 3 nanocomposites can be optimized for solar cell applications by controlling the ratio of constituent materials.