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

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.