Exploring the BiVO4/WO3 Hybrid System for Enhanced Photocatalytic Degradation and Hydrogen Evolution Reaction (HER)    

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ABSTRACT

Dual functional heterostructure of Bismuth vanadate and Tungsten trioxide (BiVO₄/WO₃) was developed and its use in the generation of hydrogen and the degradation of dyes was shown. BiVO₄ was synthesized by the sol gel method, and its heterostructure with WO₃ was created by the solvothermal method. To study the morphological, structural, and optical characteristics of BiVO₄ and BiVO₄/WO_3, X-Ray diffraction (XRD), Field emission scanning electron microscope (FESEM), UV-visible spectroscopy (UV Vis), Raman spectroscopy and X-Ray photoelectron spectroscopy (XPS) was performed. Using Electrochemical Impedance Spectroscopy (EIS) and Linear Sweep Voltammetry (LSV), the electrochemical characteristics were ascertained. When exposed to visible light, BiVO₄ alone demonstrated a 73.4% degradation efficiency for methylene blue; however, the hybrid system yielded an 87.2% degradation efficiency. In the presence of 1M KOH solution an increase in current density and a lower value of onset potential (0.388 V vs RHE) was observed for the BiVO₄/WO₃. Similarly, EIS indicated a decrease in charge transfer resistance (83.92K) in the case of hybrid. Better performance from the hybrid system in HER further presented its capacity to both clean up the environment and produce energy from renewable sources.

Significance of the Study:

This study demonstrates the potential of BiVO₄/WO₃ heterostructures as efficient photocatalysts for environmental remediation and renewable energy generation. The hybrid system’s enhanced charge transfer, reduced bandgap, and improved electrochemical performance make it a promising dual-functional material for photocatalytic dye degradation and hydrogen evolution reactions.

Summary of the Study:

BiVO₄ nanoparticles and BiVO₄/WO₃ heterostructures were synthesized using sol-gel and solvothermal methods, respectively. Characterization confirmed a reduced bandgap (2 eV) and enhanced electron transport in the hybrid system. BiVO₄/WO₃ exhibited superior photocatalytic efficiency (87.2% for methylene blue degradation) and improved HER performance with a lower onset potential (0.388 V vs. RHE) and reduced charge transfer resistance (83.92 kΩ). These findings highlight its potential for sustainable energy and environmental applications.