Dual-Function Photocatalysis in the Visible Spectrum: Ag-G-TiO2 for Simultaneous Dye Wastewater Degradation and Hydrogen Production

Photocatalytic processes offer promising solutions for environmental remediation and clean energy production, yet their efficiency under visible light remains a significant challenge. Here, we report a novel silver-graphene (Ag-G) modified TiO2 (Ag-G-TiO2) nanocomposite photocatalyst that demonstrates remarkably enhanced photocatalytic activity for both dye wastewater degradation and hydrogen production under visible and UV light irradiation. Through comprehensive characterization and performance analysis, we reveal that the Ag-G modification narrows the TiO2 bandgap from 3.12 eV to 1.79 eV, enabling efficient visible light absorption. The nanocomposite achieves a peak hydrogen production rate of 191 μmolesg-1h-1 in deionized water dye solution under visible light, significantly outperforming unmodified TiO2. Intriguingly, we observe an inverse relationship between dye degradation efficiency and hydrogen production rates in dye solutions with tap water versus deionized water, highlighting the critical role of water composition in photocatalytic processes. Our findings demonstrate sustained hydrogen production under visible light and rapid initial rates under UV irradiation, underscoring the versatility of Ag-G-TiO2 catalyst. This work not only advances our understanding of fundamental photocatalytic mechanisms but also presents a promising material for solar-driven environmental and energy applications, potentially contributing to the global transition towards sustainable technologies.