Visible-light-driven BiOBr nanosheets for highly facet-dependent photocatalytic inactivation of Escherichia coli

Bismuth oxybromide (BiOBr) nanosheets with fully exposed {001} and {010} facets are synthesized via a facile hydrothermal method. Significant differences in photocatalytic inactivation towards Escherichia coli K-12 under visible light irradiation are found to be highly dependent on the dominantly exposed facets. In comparison with BiOBr with dominant {010}-facet (B010) nanosheets, BiOBr with dominant {001}-facet (B001) nanosheets exhibit remarkably higher photocatalytic activity in bacterial inactivation. This superior activity is ascribed to the more favorable separation and transfer of photogenerated electron-hole pairs as well as more oxygen vacancies of B001 nanosheets. Due to the faster production and further accumulation of O-center dot(2)- and h(+) within a short time, the VLD photocatalyst of B001 nanosheets can completely inactivate 10(7) colony forming unit (CFU) mL(-1) (i.e. 7-log reduction) bacterial cells within 2 h; while only 1- and 6.5-log reductions of bacterial cells can be achieved within 2 and 6 h, respectively, by B010 nanosheets due to limited amounts of h(+) and O-center dot(2)- generated.