Nitrogen and Sulfur Co-Doped Carbon Quantum Dot-Engineered TiO₂ Graphene on Carbon Fabric for Photocatalysis Applications

Carbon quantum dots (CQDs) have gained considerable attention owing to their unique optoelectronic properties. However, these properties are quenched upon the aggregation of CQDs in solid-state devices, limiting their practical applications. Herein, we developed nitrogen and sulfur co-doped CQDs (NS-CQDs) by in situ carbonization process and were doped in TiO 2 -rGO (NS-CQDs-rGO-TiO 2 ) nanocomposites on flexible carbon fabric substrate for efficient solid-state photocatalytic activity. The NS-CQDs-rGO-TiO 2 photocatalyst decorated on flexible carbon fabric substrate facilitates recycling and thus improves the cycle life. The NS-CQD-rGO-TiO 2 nanocomposites exhibited improved photocatalytic degradation of 98% toward organic pollutants (methylene blue dye) than conventional aggregation-induced quenching of N-doped CQDs-rGO-TiO 2 (67%) under the same conditions. The enhanced photocatalytic activity of NS-CQD-rGO-TiO 2 nanocomposites is ascribed to NS co-doping, ultrasmall nanoparticle morphology, mesoporous structure, high surface area, modified bandgap, the resulting mixed-phase TiO 2, and formation of direct Z-scheme electron transfer under ultraviolet (UV) irradiation. Thus, this work provides insights into developing composite materials based on rutile TiO 2 for photocatalytic environmental remediation.