Preparation and photocatalytic properties TiO₂/graphene nanocomposites with sandwich structure

TiO₂/graphene nanocomposites were synthesized from graphene oxide (GO), C₁₂H₂₈N₂ and TiO₂ sol by three-step method as follows: Dodecanediamine pre-intercalating, ion exchange, and interlayer in-situ formation of TiO₂ by calcined. The properties and structures of TiO₂/graphene nanocomposites with sandwich structure were characterized by XRD, Raman, FTIR, TEM, TG, UV-Vis and PL. The photocatalytic degradation performance of TiO₂/graphene composites prepared with different amounts of TiO₂ were investigated. The crystallization of TiO₂ and the reduction of GO were significantly increased simultaneously during calcination. According to XRD and FTIR results, TiO₂ nanoparticles have formed in situ between the interlayer of graphene and anchored on graphene with chemically-bonded. Therefore, it can be concluded that the TiO₂/graphene nanocomposites with sandwich structure are prepared successfully. TiO₂/graphene composites show the best photocatalytic degradation of ciprofloxacin (CIP) when the mass fraction of TiO₂ is 65.5wt%, and the degradation rate reaches 90% after 150 min under visible light irradiation, which is higher than pure TiO₂ nanoparticles (28%, 150 min). It can be mainly attributed to the special sandwich structure with enhanced photoinduced electron-hole separation. The photocatalyst stability test shows that TiO₂/graphene nanocomposites possess high photostability and structure stability for potential practical applications in environmental purification.