Generation of Oxygen Vacancy and OH Radicals: A Comparative Study of Bi₂WO₆ and Bi₂WO_6-x Nanoplates

A comparative study of visible-light-responsive Bi₂WO₆ and oxygen-deficient Bi₂WO_6-x nanoplates was conducted. The formation of oxygen vacancy resulted in the band gap narrowing of oxygen-deficient Bi₂WO_6-x, through an elevation of both of the conduction and valence band positions. FTIR spectra revealed that much more surface hydroxyl groups have been detected after the etching process. The scavengers tests confirmed the generation of OH radicals during photochemical reaction for Bi₂WO_6-x, whereas no ^.OH radicals can be detected for pure Bi₂WO₆. The photocatalytic activities of optimized Bi₂WO_6-x on the decomposition of Rhodamine B (RhB) was three times as high as that of pure Bi₂WO₆. The improvement of photocatalytic activity on degradation of RhB and phenol can be ascribed to the synergistic effect of oxygen deficiency-induced band shifts, together with the large quantities of surface hydroxyl groups providing active sites for the generation of OH radicals (^.OH). (N)O vacancy: A comparative study of visible-light-responsive oxygen-deficient Bi₂WO_6-x nanoplates was conducted. The oxygen vacancies resulted in the band gap narrowing of oxygen-deficient Bi₂WO_6-x. The great improvement of photocatalytic activity on degradation of dyes and phenol can be ascribed to the synergistic effect of oxygen deficiency-induced band shifts, together with the large quantities of surface hydroxyl groups providing active sites for the generation of OH radicals.