In-situ construction of beta-Bi2O3/Ag2O photocatalyst from deactivated AgBiO3 for tetracycline degradation under visible light

Silver bismuth (AgBiO3, ABO) can release massive reactive oxygen species (ROS) without external support for the mineralization of organic matter. However, with the release of ROS, the catalytic activity of ABO gradually dwindled. Herein, we activated the deactivated ABO (ABO-DA) by simple calcination method to obtain a series of bismuth and silver compounds. With increasing calcination temperature, the components changed to ABO-DA@Ag2O, beta-Bi2O3/Ag2O, and then alpha-Bi2O3/Ag2O, respectively. Meanwhile, the morphology changed from nanosheets to porous nanosheets, and then to porous gullies. Comparison with the others, ABO-290 (beta-Bi2O3/ Ag2O) activated at 290 degrees C showed the optimum degradation efficiency (78.0% within 2 h) and highest apparent reaction rate constant (3.7 times than ABO-DA) for tetracycline (TC) degradation. That was because that ABO-290 had the lowest recombination probability, minimum Nyquist plot radius and strongest photo response capability. In addition, the possible degradation path of TC by ABO-290 was proposed based on the results of GC-MS and LC-MS. This study not only deepens the comprehension on the deactivation of silver bismuthate catalysts, but also opens a novel perspective for the construction of highly efficient photocatalysts from deactivated catalysts.