Role of hydroxylation modification on the structure and property of reduced graphene oxide/TiO₂hybrids

To extend the spectra response of TiO2and enhance its photocatalytic activity, surface modification and catalyst supporter have attracted great attention. In this report, a simple and versatile approach has been developed to hydroxylate the reduced graphene oxide/TiO2hybrids (OH-rGO/TiO2) by UV-microwave method, and the enhanced mechanisms of hydroxylation were analyzed in details. Experimental results show that TiO2nanocrystals@OH-TiO2heterojunctions formed on rGO sheets in situ by UV/H2O2process. Hydroxylation not only can induce many surface defects (Ti3+, O vacancy and Ti-OH) on the surface of TiO2, but also change the color into yellow and strengthen the interaction between rGO and TiO2. OH-rGO/TiO2hybrids showed excellent durability for high-concentration dyes, and exhibited strong adsorbability and photocatalytic activity. These enhancements are attributed to the excellent property of rGO and surface defects of TiO2induced by hydroxylation, which expand the light absorption up to 600 nm, benefit to the self-dispersion of hybrids, and improve the adsorption dynamic and charge transfer with lower carrier's recombination.