AgBr nanoparticles decorated 2D/2D GO/Bi2WO6 photocatalyst with enhanced photocatalytic performance for the removal of tetracycline hydrochloride

Bismuth tungstate (Bi2WO6) was well known for its low price, nontoxicity and stability in the removal of organic pollutions. However, poor visible light absorption and fast carrier recombination led to its moderate activity. Therefore, a Z-scheme photocatalyst constructed by Bi2WO6 nanosheets, graphene oxide (GO) and silver bromide (AgBr) nanoparticles was successfully prepared. Previous reports suggested that Z-scheme structure based on Bi2WO6 nanosheets could obtain more active sites. And characterization results clarified that the addition of AgBr brought broadened visible light response range, inducing more photocarrier generation. Meanwhile, the optimized Z-scheme composite 15%AgBr/5GO/Bi2WO6 (15A/5G/BW) possessed accelerated interfacial charge separation and transfer, which was resulted from excellent electron conductivity in GO. As a result, 15A/5G/BW exhibited superior photocatalytic activities for tetracycline hydrochloride (TC). The highest degradation efficiency could reach 84% under visible light illumination, and the kinetic constant was 0.0515 min−1 which was approximately 4.60 and 3.16 times higher than that of AgBr and Bi2WO6, respectively. Furthermore, liquid chromatography-mass spectrometry (LC-MS) and trapping experiments revealed possible TC degradation pathways and main active radicals during photocatalysis process. A facial strategy for rational design of ternary photocatalyst towards the degradation of refractory antibiotics was proposed.