Abstract: The reaction interface microenvironment is an important factor that affects photocatalytic reaction performance. In this study we construct a highly efficient triphase interface reaction system by regulating the surface wettability for photocatalytic oxidation of organic compounds. Titanium dioxide (TiO2) nanoparticle is used as a model photocatalyst, polydimethylsiloxane (PDMS) is grafted onto the surface to enhance the hydrophobicity. Experimental results show that the presence of hydrophobic a PDMS layer enables the formation of a gas-liquid-solid triphase coexisting microenvironment at the reaction interface, which increases the interfacial oxygen (O2) concentration. Meanwhile, the hydrophobic surface layer enhances the adsorption capability of organic molecule. Such synergistic effect promotes the generation of superoxide radicals (?O2- ) and hydroxyl radicals (?OH) and enhances the photocatalytic oxidation reaction. This work provides a novel approach to design and construction of efficient catalytic reaction systems.

Key words: Wettability, Reaction interface microenvironment, Triphase interface; Photocatalysis, TiO₂