Construction of chalcogenide Cu2BaVS4 nanograins from nanocubes via solvothermal synthesis for photoelectrochemical hydrogen/oxygen evaluation in alkaline media and dye degradation applications

Abstract

In this investigation, we report the synthesis of quaternary chalcogenide semiconductor Cu₂BaVS₄ (CBVS) nanostructures through the solvothermal method for the first time. Various methods of characterization involving the X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), Raman spectroscopy, and UV-visible and photoluminescence spectroscopy were applied to analyze the properties of CBVS nanostructures. XRD analysis represents the orthorhombic crystal structure of CBVS with a calculated average crystallite size of 27 nm. The SEM images indicate a tetragonal to grain-like morphology with 50–60 nm diameter. CBVS nanoparticles show absorption spectra within the UV-Visible range of about 220–320 nm. The optical band gap calculated for CBVS nanoparticles using PL spectra is 1.55 eV. The electrochemical performance of the produced nanostructures for energy production was also revealed in the dark and under light. For the hydrogen evolution reaction (HER), the Cu₂BaVS₄/NF₅₀₀ electrodes showed low overpotentials of 256 mV with a Tafel slope of 105 mV dec⁻¹ under visible light, indicating better catalytic activity. The Cu₂BaVS₄/NF₅₀₀ electrode showed a reduced overpotential of 112 mV at a current density of 10 mA cm⁻², with a Tafel slope of 37 mV dec⁻¹ under visible light, indicating a rapid and effective OER. Based on these findings, these nanostructures show promise as electrode materials in water-splitting applications.