▎ 摘　　要

Graphene-supported BiFeO3 (rG-BiFeO3) was synthesized by the hydrothermal method and used for the efficient removal of ammonia under visible light. X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy were conducted to characterize the rG-BiFeO3. The specific surface area of the rG-BiFeO3 catalyst was 48.6 m(2)/g, larger than that of BiFeO3 (21.0 m(2)/g). When used as a heterogeneous photocatalyst, rG-BiFeO3 achieved 91.20% degradation of a NH3-N solution (50 mg/L) at pH = 11 under visible-light irradiation in the absence of hydrogen peroxide. The degradation of ammonia followed pseudo-first-order kinetics, and the catalyst retained high photocatalytic activity after seven reaction cycles. Study of the mechanism showed that the holes, superoxide anion radicals, and hydroxyl radicals, arising from the synergy between graphene and BiFeO3, oxidized NH3 directly to N-2. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.