One-pot engineering TiO₂/graphene interface for enhanced adsorption and photocatalytic degradation of multiple...

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 TiO₂ 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%), TiO₂ 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%), TiO₂ aggregates were a mixture of nanosheets, nanoparticles and nanorods. 25%RGO/TiO₂ also had 175% higher surface area (146 m² g^-1), 95% larger volume (0.339 cm³ g^-1) and smaller band gap than 6%RGO/TiO₂. More importantly, 25%RGO/TiO₂ demonstrated higher adsorption efficiency (25%) and four times faster degradation rate than TiO₂ (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 TiO₂ and RGO, which not only provided more active sites to capture pollutants, but enhanced charge transfer (3 μA cm^-2, five times higher than TiO₂). This work offers a promising way to purify water through engineering new material structure and integrating adsorption and photodegradation technologies.