Visible light driven CuBi2O4/Bi2MoO6 p-n heterojunction with enhanced photocatalytic inactivation of E. coli and mechanism insight

[Display omitted] •Novel CuBi2O4/Bi2MoO6 p-n heterojunction was prepared for photodisinfection.•CuBi2O4/Bi2MoO6-0.5 displayed the strongest photocatalytic performance.•Reactive species h+, e−, •O2−played the primary role in the potocatalytic system.•The leakage and damage of protein and DNA resulted in the death of E. coli.•The disrupted cell membrane of E. coli was verified with SEM and fluorescence stain. Here, a novel CuBi2O4/Bi2MoO6 (CBO/BMO) p-n heterojunction was fabricated and exhibited markedly improved photocatalytic inactivation capacity of E. coli cells under visible light excitation (λ > 420 nm) compared with pure CuBi2O4 and Bi2MoO6. The CBO/BMO-0.5 hybrid displayed the highest photoinactivation ability which could completely inactivate the E. coli cellswithin 4 h. The mechanism of photocatalytic disinfection towards E. coli of CBO/BMO heterojunctions was attributed to the disruption of cell-membrane, leakage and damage of cellular content including total protein and DNA as verified with SEM, fluorescence-base dead/live stain, sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) and agarose gel electrophoresis (AGE). Additionally, the scavenge experiments showed that the reactive species h+, e− and •O2−play the predominant role in the photocatalytic system of CBO/BMO hybrids. The improved photocatalytic activity of CBO/BMO composites was mainly attributed to the promotion of spatial separation and migration rate of photoproduced electron-hole pairs, enhancement of visible light absorption and more generation of reactive species (•O2−) on the interface of catalyst and water which was demonstrated by nitroblue tetrazolium (NBT) and EPR. Our work indicated that construction of CuBi2O4/Bi2MoO6 p-n heterostructure photocatalyst is a promising environmental friendly alternative method to deal with the biohazards of pathogenic microorganisms.