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

In the quest for sustainable and efficient hydrogen peroxide (H2O2) 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 (TiO2) nanoparticles. By meticulously optimizing the DA-to-TiO2 molar ratio, we achieved an optimal photocatalyst composition, designated as TiO2@PDA, that exhibits remarkable photocatalytic efficiency in H2O2 production under simulated solar irradiation. The synthesis process, characterized by adjusting the pH to favor PDA polymerization and ensuring uniform coating on TiO2 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 TiO2@PDA significantly outperforms both pristine TiO2 and PDA in H2O2 production, indicating synergistic effects between TiO2 and PDA by reducing the decomposition rate of TiO2. PDA can play dual roles of photocatalytic active sites and protective layer on the surface of TiO2. Additionally, this study demonstrates the stability and reusability of TiO2@PDA, highlighting its potential for eco-friendly and cost-effective H2O2 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.