Near-infrared responsive upconversion glass-ceramic@BiOBr heterojunction for enhanced photodegradation performances of norfloxacin.

An efficient luminous and electronic energy transmission BiOBr based near-infrared (NIR) responsive heterojunction photocatalyst was successfully fabricated through growing BiOBr nanosheets on the superficial layer of the SrF2-Bi2O3-B2O3/Yb3+,Tb3+ (SBBF) upconversion glass-ceramic (GC) via a facile in-situ etching GC method (FIEG). A high norfloxacin (NOR) degradation rate of 56% was obtained under 180 min NIR light irradiation for the NIR GC photocatalyst (SBBF/BiOBr-10), and it possesses much enhanced photocatalytic activity compared with that of pure BiOBr under UV-vis-NIR light irradiation. Wherein six intermediate products were identified in the NOR photodegradation process and the possible degradation pathways were proposed. B3+, Yb3+ and Tb3+ ions in GC can be doped into BiOBr layer during the FIEG process. The core-shell structure of the GC@BiOBr heterojunction photocatalyst is in favor of increasing charge transport and reducing the recombination rate of excited carriers, and it efficiently harvests NIR photons to emit UV and visible light upconversion emissions, which can be utilized during the photocatalysis process. The photocatalyst can be facilely regenerated via HBr etching again, moreover, the low-cost and less time requirement promote the possibility of large-scale fabrication of the efficient photocatalysts.