Crystallization of microporous TiO2 through photochemical deposition of Pt for photocatalytic degradation of volatile organic compounds.

The photocatalytic mineralization efficiency of volatile organic compounds (VOCs) is determined by adsorption of reactants, separation of charge carriers, and reaction activity of catalyst surface. Herein, we provide a strategy to synthesize a novel catalyst, namely, PhPt-Micro, which is characterized by high adsorption ability, charge separation efficiency, and surface reaction activity. Toluene was chosen as the model VOC. The effects of photochemical deposition of Pt on the physical properties of microporous amorphous TiO2 (Micro) and toluene mineralization were studied using N2 adsorption/desorption, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, GC-flame ionization detection, and surface photovoltage spectroscopy (SPS) analyses. After photochemical treatment, the structure of Micro was optimized, and Pt nanoparticles were successfully deposited at the outlet of electrons on the catalyst surface. SPS result proved that the optimized structure enhanced the separation efficiency of charge carriers and the migration of photo-generated electrons to the PhPt-Micro surface. The quasi-equilibrium adsorption amount of toluene over PhPt-Micro was two times higher than that with commercial nano TiO2 (P25). The micropores concentrated toluene on the catalyst surface and hindered intermediate desorption. The mineralization efficiency of toluene over PhPt-Micro was 2.4 and 5.9 times higher than those over Micro and P25, respectively.