Hydrogen Generation from Wastewater-Derived Organics via Solar Photocatalysis Using Low-Cost Cu-TiO₂ Composites

Recent research has focused on developing Cu-based TiO₂ photocatalysts for sustainable hydrogen production via solar photoreforming of organic compounds typically present in urban and industrial wastewater. Copper, either in solution or integrated into TiO₂, forms heterojunctions that enhance photocatalytic H₂ generation by improving visible light absorption and promoting charge carrier separation. This study investigates hydrogen evolution from oxygenated organic compounds, such as alcohols and carboxylic acids, using Cu-modified TiO₂-P25 catalysts synthesized via a simple in situ photodeposition method. The incorporation of Cu nanoparticles significantly alters the optical properties of TiO₂, boosting its activity under solar irradiation. Experimental results demonstrate notably higher hydrogen production rates with Cu-TiO₂ compared to bare TiO₂-P25. For instance, glycerol yielded 5.5 μmol H₂/min with Cu-TiO₂, versus 2.1 μmol/min with unmodified TiO₂. However, no enhancement was observed with benzyl alcohol, 2-propanol, or acetic acid, suggesting that hydrogen evolution is substrate-specific and likely influenced by adsorption behavior and oxidation pathways. A mechanism has been proposed to explain these variations based on light absorption and charge transfer dynamics.