“…In all these samples, two absorption peaks at around 3440 cm −1 and 1623 cm −1 are assigned as the stretching and bending vibrations of the hydroxyl group (–OH), respectively. 38,39 For the BiOCl sample, the absorption band at 529 cm −1 belongs to the vibration of the Bi–O stretching mode, which agrees well with earlier reports. 24,40 For Bi 2 WO 6 and Bi 2 WO 6 /BiOCl-3 samples, the absorption peak 41 at about 577 cm −1 also corresponds to the vibration of the Bi–O stretching mode, and the sharp absorption peak 42 at 733 cm −1 is indexed to W–O–W stretching, bending and lattice modes.…”