Selective photodegradation and enhanced photo electrochemical properties of titanium dioxide-graphene composite with exposed (001) facets made by photochemical method

摘要

We report for the first time, titanium dioxide-graphene (HRTiO2-Gr) composite with exposed (001) facets by a photochemical reduction method and its selective photocatalytic properties. The drastic reduction in the photoluminescence intensity of the composite indicates effective charge separation. The composite with 10 wt% Gr (HRTiO2-Gr10) exhibits higher photodegradation (PD) of methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) compared to that of the P25. The composite exhibits selectivity in its PD properties, with higher photocatalytic activity for the positive dyes, MB and RhB. This is attributed to the synergistic effect of the unique pore morphology and the surface properties of the composite due to the negative Gr. Higher selectivity in the PD of the positive dyes is observed in the mixture of the positive and negative dyes. In addition, HRTiO2-Gr10 exhibits lower charge transfer resistance than that of the HRTiO2 and P25. The improved charge transfer resistance is assigned to the thin Gr sheets which improves the charge transfer at the interfaces. Our results suggest that the PCR method of preparation facilitates higher loading of high quality thin Gr sheets with improved dispersion and interaction with TiO2 thus imparting the composite selective and enhanced photocatalytic properties. (C) 2015 Elsevier B.V. All rights reserved.