Synergistic photoactivity regulation of Bi2WO6 with highly exposed {0 0 1} facets and oxygen vacancies by base-metal-ion dopant for enhanced reduction of pharmaceutical compounds

Abstract

Herein, base metal-doped Bi2WO6 nanosheets with a large proportion of exposed {001} facets and oxygen vacancies were prepared and exhibited greatly enhanced photoactivity for removing four kinds of pharmaceutical compounds under visible-light irradiation. Results in this study indicated that both Zn- and Cu-doped nanosheets possessed optimal photocatalytic activity due to their improved light-harvesting ability and transport efficiency of photo-induced carriers, but Cu-doped nanosheets showed better activity than Zn-doped samples attributed to the existence of high-oxidation-state Cu3+ ions. Meanwhile, it was found that the optimal photodegradation condition for the metal ion-doped photocatalysts was neutral pH, 10 mg/L of pollutants concentration and 0.3 g/L of catalyst dosage. The degradation rate of Zn-doped samples was different from Cu-doped ones, while the Zn-doped samples showed almost 100 % degradation rate for hydrocortisone and 87.8 % for atenolol but the Cu-doped ones showed 100 % for hydrocortisone, 99.3 % for bezafibrate, and 82.1 % for carbamazepine. It was found that O2− and 1O2 were the dominant active species for photodegradation and the breakdown products were identified to be hypotoxic generally.