Enhanced photocatalytic performance of KNbO3(100)/reduced graphene oxide nanocomposites investigated using first-principles calculations: RGO reductivity effect

Although a number of various reduced graphene oxide (RGO)-based nanomaterials with enhanced photocatalytic performance have recently been characterized, the effect of RGO reductivity on their performance is still not clear. Herein, KNbO ₃ (100) surface modification with three RGO sheets of different reductivity is investigated using first-principles calculations, revealing that increasing RGO reductivity enhances the photocatalytic performance of KNbO ₃ (100)/RGO nanocomposites. In contrast to CeO ₂ /RGO nanocomposites, the O atoms of RGO inhibit the photoactivity of KNbO ₃ /RGO nanocomposites by restraining the effect of inducing a red shift of the corresponding photocatalytic absorption spectra by C 2p states. Increased RGO reductivity extends its absorption edge to the visible light region of the optical absorption and also promotes charge transfer from the KNbO ₃ (100) surface to RGO sheets, in contrast to the behavior observed for g-C ₃ N ₄ /RGO composites. Overall, this work provides a reasonable explanation of controversial experimental results obtained previously, paving the way to the development of highly efficient RGO-based photocatalysts and promoting further photocatalytic applications of KNbO ₃ /RGO nanocomposites.