Bi2Ti2O7/TiO2/RGO composite for the simulated sunlight-driven photocatalytic degradation of ciprofloxacin

Titanium dioxide (TiO2) modified bismuth titanate (Bi2Ti2O7) heterojunction was supported on reduced graphene oxide (RGO) to obtain Bi2Ti2O7/TiO2/RGO composite by simple solvothermal method. Neither toxic reductant nor toxic solvent was used. The structural characterization shows that spherical Bi2Ti2O7/TiO2 nanoparticles are loaded on silk-like transparent RGO. By contrast with each individual component, the prepared Bi2Ti2O7/TiO2/RGO composite shows significantly enhanced photocatalytic performance on the degradation of ciprofloxacin (CIP) under simulated sunlight. The degradation efficiency of CIP using Bi2Ti2O7/TiO2/RGO composite as the catalyst reaches 95% in 180 min and maintains at 88% after 5 photocatalytic reaction cycles. The enhancement of photocatalytic performance of Bi2Ti2O7/TiO2/RGO(5) composite is due to the synergistic effect among Bi2Ti2O7, TiO2 and RGO. Moreover, compared with other recently reported bismuth-based catalysts, Bi2Ti2O7/TiO2/RGO exhibits higher photocatalytic activity, or shows comparable activity but with less dosage used. Free radical scavenger experiments were also carried out to explore the photocatalytic degradation mechanism.