Double optimization of 2D Bi2WO6 flowers into sheets with AgBr and Ag loading towards enhanced acetaminophen removal and H2 production

• Ag-loaded Bi 2 WO 6 /AgBr heterojunction synthesized via simple hydrothermal and photo-deposition. • Both AgBr loading and Ag loading were optimized. • Acetaminophen removal of 77.1% was achieved under visible light irradiation and hydrogen production in full spectrum. • Bi 2 WO 6 acted as the primary catalyst in ACE removal, while AgBr was the primary catalyst in H 2 production. In this study, one pot Bi 2 WO 6 -AgBr (BWA) heterojunction is constructed via a simple hydrothermal method, with further optimizations of Ag nanoparticle loadings. Morphological transformations were observed from flower to 2D sheets for Bi 2 WO 6 with increasing amounts of AgBr loadings. Double optimization with AgBr and Ag loadings elevated the photocatalytic performance of the 1Ag@BWA 0.5, evidenced via acetaminophen removal and H 2 production. TEM/HAADF image and mapping images were utilized to visualize the Ag nanoparticle with a size ranging from 35 to 70 nm. Acetaminophen (ACE) was degraded under visible light irradiation, wherein 1Ag@BWA 0.5 obtained a rate constant of 11.2 × 10 -3 min −1 much higher than BW (k = 4.83 × 10 -3 min −1 ) and AgBr (k = 3.7 × 10 -3 min −1 ). A series of experiments with varying pH, interference ions, and multiple ACE concentrations were also performed. ICP-MS showed that Ag + from AgBr converted to Ag 0 post-irradiation; however, leaching into the used ACE solution was the bare minimum. Also, 1 Ag@BWA 0.5 produced up to 225.36 μmol.g −1 .h −1 of H 2 , ∼4 times higher than bare AgBr (53.06 μmol.g −1 .h −1 ) and 20 times higher than pristine BW (10.9 μmol.g −1 .h −1 ). The used photocatalyst depicted the formation of new phases and shift in oxidation states of constituent elements in 1Ag@BWA 0.5. The work function of Ag nanoparticles was placed between Bi 2 WO 6 and AgBr, which could have facilitated the Z-scheme mechanism in our Ag-loaded heterojunction.