Morphology Adjustment of TiO2 Nanostructures for Enhanced Photocatalytic Properties

Abstract

Titanium dioxides (TiO2) nanoarchitectures including microspheres surrounded by nanosheets were synthesized using simple, quick and effective hydrothermal method with moderate temperature (150 °C). We systematically investigated how reaction time affected final morphologies of TiO2. At reaction times equal to 4 and 8 hours (named as TS-4 and TS-8, respectively), TiO2 formed with morphology of irregular microspheres. At longer reaction times (12 hours, named as TS-12), urchin-like TiO2 nanocrystals formed. Photocatalytic activities of the formed TiO2 with different morphologies were evaluated against decomposition of methylene orange and blue (MO and MB, respectively) as well as rose-bengal (RB). Urchin-like TiO2 demonstrated high degradation ratio similar to the commercial catalyst PS 25 on MO (96%). Degradation ratios of samples synthetized for 4 and 8 hours were much lower: 60 and 80%, respectively. During 30 minutes reaction time, TiO2 with urchin-like morphology showed much higher selectivity towards neutralization of MB (99.5%) than towards MO (73%) and RB (88.7%).