Highly efficient three-dimensional flower-like AgI/Bi2O2CO3 heterojunction with enhanced photocatalytic performance

Abstract

Novel AgI/Bi2O2CO3 composites, in which AgI nanoparticles were highly dispersed on Bi2O2CO3 nanosheets, acting as building blocks for the assembly of three-dimensional flower-like microspheres, were prepared by a simple in situ deposition process. The as-prepared samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy and UV–visible diffuse reflectance spectroscopy. The photocatalytic activity was investigated for the degradation of RhB under visible light irradiation. The results showed that the as-prepared AgI/Bi2O2CO3 heterojunctions exhibited a much higher activity than pure Bi2O2CO3 and AgI. When the amount of AgI was controlled at 25% (molar ratio), the highest photocatalytic performance could be achieved. The photoluminescence (PL) spectra indicated that the recombination of photogenerated electron–hole pairs was suppressed effectively due to the formation of heterojunction between AgI nanoparticles and Bi2O2CO3 nanosheets. Trapping experiments indicated that h+ and ⋅O2− radicals were the main reactive species responsible for the degradation of RhB in the photocatalytic system. Furthermore, the good stability of AgI/Bi2O2CO3 composites was demonstrated by four successive photodegradations of RhB under visible light.