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 of 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 O2–, while the photoexcited holes of the valence band of AgI could oxidize organic pollutants in water.