p-AgI anchored on {001} facets of n-Bi2O2CO3 sheets with enhanced photocatalytic activity and stability

A close-connected p-AgI/n-Bi2O2CO3 heterojunction was synthesized by a one-step co-crystallization method. The visible-light-driven photoactivity of AgI was exceptionally enhanced by nearly 5 times through in-situ close contact with Bi2O2CO3. After seven cycling measurements, the photodegradation rate of 2-chlorophenol could be maintained at 88% and no Ag+ and Bi3+ could be detected in the reaction solution, indicating high photostability of the heterojunction photocatalyst. On the basis of the characterization of morphology, X-ray diffraction, Fourier-transform infrared spectra and X-ray photoelectron spectroscopy, AgI nanoparticles were selectively anchored on active {001} facets of layered Bi2O2CO3 sheets, and a strong interfacial interaction between p-AgI and n-Bi2O2CO3 was observed, which enhanced effective separation and transfer of the photo-generated electron-hole pair from AgI, resulting in the high photoactivity and photostability of AgI for the degradation and mineralization of 2-chlorophenol under visible light. By the studies of electron spin resonance and other experiments, the charge transfer process at the interface cif p-AgI/n-Bi2O2CO3 was verified that the photoexcited electrons of the conduction band of AgI transferred to the conduction band of Bi2O2CO3 to react with surface adsorbed oxygen into O-2(center dot-), while the photoexcited holes of the valence band of AgI could oxidize organic pollutants in water. (C) 2016 Elsevier B.V. All rights reserved.