One-pot engineering TiO ₂ /graphene interface for enhanced adsorption and photocatalytic degradation of multiple organics

Abstract

Abstract It is challenging to design a multifunctional structure or composite for the simultaneous adsorption and photocatalytic degradation of organic pollutants in water. Towards this goal, in this work we innovatively engineered interfacial sites between TiO 2 particles and reduced graphene oxide (RGO) sheets by employing an in situ one-pot one-step solvothermal method. The interface was associated with the content of RGO, solvothermal time and solvent ratio of n-pentanol to n-hexane. It was found that with a moderate amount of RGO (25%), TiO 2 nanoparticles were well dispersed on the surface of the RGO or wrapped by the RGO, thus leading to full contact and strong interactions to form a Ti–O–C interfacial structure. But with low content of RGO (6%), TiO 2 aggregates were a mixture of nanosheets, nanoparticles and nanorods. 25%RGO/TiO 2 also had 175% higher surface area (146 m 2 g −1 ), 95% larger volume (0.339 cm 3 g −1 ) and smaller band gap than 6%RGO/TiO 2 . More importantly, 25%RGO/TiO 2 demonstrated higher adsorption efficiency (25%) and four times faster degradation rate than TiO 2 (0%). It also exhibited good capability to eliminate multiple organics and stable long-term cycle performance (up to 93% retention after 30 cycles). Its superiority was attributed to the large surface area and unique interface between the TiO 2 and RGO, which not only provided more active sites to capture pollutants, but enhanced charge transfer (3 μ A cm −2 , five times higher than TiO 2 ). This work offers a promising way to purify water through engineering new material structure and integrating adsorption and photodegradation technologies.