Enhanced Photocatalytic Kinetics of Hybrid TiO₂ Photocatalysts Sheathed with Polydopamine toward Efficient H₂O₂ Production

In the quest for sustainable and efficient hydrogen peroxide (H 2 O 2 ) production, this study introduces an organic and inorganic hybrid photocatalyst synthesized through a facile self-polymerization of dopamine hydrochloride (DA) to polydopamine (PDA) on titanium dioxide (TiO 2 ) nanoparticles. By meticulously optimizing the DA-to-TiO 2 molar ratio, we achieved an optimal photocatalyst composition, designated as TiO 2 @PDA, that exhibits remarkable photocatalytic efficiency in H 2 O 2 production under simulated solar irradiation. The synthesis process, characterized by adjusting the pH to favor PDA polymerization and ensuring uniform coating on TiO 2 surfaces, is thoroughly detailed. Comprehensive material characterization confirmed the successful formation of the PDA layer and elucidated the structural and chemical properties of hybrid photocatalysts. Photocatalytic experiments revealed that TiO 2 @PDA significantly outperforms both pristine TiO 2 and PDA in H 2 O 2 production, indicating synergistic effects between TiO 2 and PDA by reducing the decomposition rate of TiO 2 . PDA can play dual roles of photocatalytic active sites and protective layer on the surface of TiO 2 . Additionally, this study demonstrates the stability and reusability of TiO 2 @PDA, highlighting its potential for eco-friendly and cost-effective H 2 O 2 production. This work not only presents an approach to hybrid photocatalyst design but also contributes to the development of sustainable processes for chemical production, aligning with the principles of green chemistry.