Visible-light-driven, hierarchically heterostructured, and flexible silver/bismuth oxyiodide/titania nanofibrous membranes for highly efficient water disinfection

Abstract

Constructing a flexible inorganic membrane photocatalyst for efficient visible-light-driven water disinfection is highly desired but remains a great challenge. Herein, we fabricated a flexible and heterostructured silver/bismuth oxyiodide/titania (Ag/BiOI/TiO2) nanofibrous membrane by combining the electrospinning technique with simple successive ionic layer adsorption and reaction (SILAR) and photodeposition process. In this ternary nanocomposite, ultrathin BiOI nanoplates were firmly anchored onto TiO2 nanofibers, while Ag nanoparticles were uniformly decorated on the surface of both BiOI and TiO2. Benefiting from the large surface area, improved visible-light absorption, and the effective interfacial charge transfer induced by multi-heterojunctions, the resultant Ag/BiOI/TiO2 membrane exhibited superior photocatalytic disinfection activity (7.5 log inactivation of E. coli within 1 h) under visible light illumination. Moreover, the plasmonic Z-scheme charge transfer mode was also proposed for Ag/BiOI/TiO2 system according to the band structure and reactive species analysis. More significantly, the Ag/BiOI/TiO2 membrane-based photoreactor could be facilely constructed for high-efficiency disinfection of high volume contaminated water, and the membrane still maintained good structural integrity and mechanical flexibility after utilization. This work may open up new avenues for designing and constructing flexible high-performance photocatalytic membranes for environmental applications.