Improved photocatalytic performance over AgBr/ZnO under visible light

AgBr nanoparticles modified ZnO have been successfully synthesized by using cetyltrimethylammonium bromide as the bromide source and stabilizer. X-ray diffraction and X-ray photoelectron spectroscopy confirmed the loading of AgBr nanoparticles on ZnO support. The transmission electron microscopy showed that AgBr nanoparticles with small size were well dispersed on the surface of ZnO support. UV-visible diffuse reflectance spectra displayed the absorbance of AgBr/ZnO composite was much higher than that of pure ZnO in the visible light range. The photocatalytic activities of degradation Rhodamine B dye under visible light over AgBr/ZnO catalyst were markedly enhanced compared with pure ZnO. The improved photocatalytic activities may be attributed to the synergetic effects including enhanced visible light absorption, narrowed band gap and effective separation of photogenerated e^--h⁺ resulted from the highly dispersed small nanosized AgBr. Moreover, the possible mechanism was tentatively proposed based on the photoluminescence spectra and surface photovoltage spectroscopy.