Preparation of graphdiyne-doped TiO2/SiO2 composite for enhanced photocatalytic activity

Enhancing the efficiency of visible light degradation is important for the actual application of TiO2/SiO2 (Ti/Si) composite materials for waste water treatment. In this manuscript, graphdiyne-doped TiO2/SiO2 (Ti/Si/GDY) (the Ti/Si composite exhibits a spherical shape with a diameter between 200 and 500 nm) composite material was successfully prepared using a hydrothermal method, which was utilized as photocatalyst for the photocatalytic degradation of methylene blue (MB) in aqueous solution under visible light illumination. Studies showed that Ti/Si/GDY-0.8 wt% exhibited superior photocatalytic degradation efficiency (91.8%) under visible light illumination than other composite materials such as Ti/Si/GDY-0.6 wt% (87.9%), Ti/Si/GDY-1.0 wt% (85.9%), and bare Ti/Si composite (32.3%). Moreover, Ti/Si/GDY also showed a higher photocatalytic degradation efficiency than other carbon materials (graphene (GR) and carbon nanotube (CNT) composited Ti/Si (Ti/Si/GR, Ti/Si/CNT)). The studies of the possible mechanism for the degradation of MA indicated that h+ was the major substance for the smooth degradation of methylene blue. Such a high efficiency photocatalyst might be also useful for the degradation of other contaminates in waste water or air.