Photocatalytic performance of single and co-doped Ag/Ni-BaWO4 for H2 production, methyl violet degradation, and bacterial disinfection under visible light irradiation

Abstract

This study investigates the photocatalytic performance of single and co-doped Ag/Ni-BaWO₄ for hydrogen (H₂) production, Methyl Violet (MV) dye degradation, and bacterial disinfection under visible light irradiation. BaWO₄ samples doped with silver (Ag) and nickel (Ni) were synthesized using the precipitation method and characterized using various techniques, including SEM, XRD, Raman, and XPS. The SEM images revealed spherical morphology, while XRD showed slight shifts in diffraction peaks due to doping. Photoluminescence (PL) spectra indicated that the co-doped samples had the highest luminescence intensity, attributed to charge separation enhancement, with band gap energies of 2.55 eV, 2.54 eV, and 2.56 eV for Ag-BaWO₄, Ni-BaWO₄, and Ag/Ni-BaWO₄, respectively. The co-doped Ag/Ni-BaWO₄ exhibited the highest photocatalytic activity, with a degradation efficiency of 98% for MV compared to 71% for Ni-BaWO₄ and 84% for Ag-BaWO₄. For hydrogen production, the optimal formic acid concentration was 750 ppm, and the catalyst dosage was 0.2 g, resulting in high hydrogen yields over 4 h. The Ag/Ni-BaWO₄ catalyst also displayed strong antibacterial activity, achieving 100% inactivation of Escherichia coli at 1000 µg/ml but showing no significant effect on Enterococcus faecalis. The study highlights Ag/Ni-BaWO₄ as a promising photocatalyst for environmental remediation and H₂ production, driven by visible light. The proposed mechanism involves charge separation, electron–hole pair generation, and radical formation, contributing to efficient photocatalytic reactions.