Visible-light-activated N-doped CQDs/g-C3N4/Bi2WO6 nanocomposites with different component arrangements for the promoted degradation of hazardous vapors

Abstract

To investigate whether the arrangement of componentsin multi-composite photocatalysts may affect their photocatalytic properties, due to different charge-transfer routes, two ternary-nanocomposite photocatalysts with different component arrangements, comprising N-doped carbon quantum dots (NCQDs), g-C3N4 (CN), and Bi2WO6 (BWO) (hereafter referred to as NCQDs/CN/BWO), were developed, and the photocatalytic degradation of model hazardous vapors under visible-light illumination was investigated. Type I NCQDs/CN/BWO, which was developed by the combination of NCQDs/BWO and CN, exhibited photocatalytic ability superior to that of type II NCQDs/CN/BWO, which was developed by the combination of CN/BWO and NCQDs; the superior photocatalytic ability corresponded to the dual properties of NCQDs: charge mediation and upconversion photoluminescence. Moreover, the photocatalytic ability of NCQDs/CN/BWO was greater than those of the reference catalysts; in addition, this photocatalyst exhibited outstanding photochemical stability. Additionally, the effects of CN/(BWO + CN) weight ratio of the CN/BWO dual nanocomposites and the NCQDs/(BWO + CN + NCQDs) weight percentage of NCQDs/CN/BWO ternary nanocomposites on the pollutant removal efficiency were investigated. The plausible mechanisms over the two NCQDs/CN/BWO photocatalysts for the degradation of hazardous vapors were discussed. The component arrangement approach proposed herein afforded a technique toward the perceptive development of novel multi-component heterostructures for the photocatalytic degradation of hazardous vapors.