Augmenting reactive species over MgIn2S4-In2O3 hybrid nanofibers for efficient photocatalytic antibacterial activity

Abstract

Narrow bandgap semiconductor MgIn2S4 has been readily grown onto In2O3 nanofibers by an in situ growing method. The so-formed MgIn2S4-In2O3 hybrid nanofibers are characterized by strong visible light absorption and intimate MgIn2S4/In2O3 heterointerfaces. Under visible light illumination (λ ≥ 400 nm), the hybrid nanofibers demonstrate an exceptionally high photocatalytic activity for Escherichia coli (E. coli) disinfection, outcompeting pristine MgIn2S4, naked In2O3 nanofibers, and many other photocatalytic systems reported. Specifically, the hybrid nanofibers achieve a 7 log reduction in viable cells for merely 20 min illumination while pristine MgIn2S4 and naked In2O3 nanofibers alone are almost inactive. Further analysis indicates that the hybrid nanofibers essentially form a type-II semiconductor heterojunctions which enable spatial separation of photocarriers. Owing to the intimate heterointerfaces, photocarriers can be promptly separated and accumulated respectively in In2O3 and MgIn2S4 thereby allowing continuous generation of copious reactive species for disinfection. This work signifies the usefulness of heterointerfaces in promoting photocarrier separation and provides a useful strategy to upgrade photocatalytic performance from otherwise almost inactive semiconductors.