Investigation on the impact of green synthesized N-C-dots decoration over photocatalytic efficiency of S-g-C3N4/ZnO

Abstract

Herein, green synthesized N-doped carbon dots (N-C-dots) and in-situ produced binary composites of sulphur-doped graphitic carbon nitride (S-g-C₃N₄) and ZnO have been hydrothermally treated to develop their ternary composite, i.e., N-C-dots/S-g-C₃N₄/ZnO (N-C-dots/SgCN/ZnO) to investigate the impact of N-C-dots decoration over SgCN/ZnO for photocatalytic decomposition of rhodamine B (RhB) dye. The obtained N-C-dots are almost spherical and exhibited remarkable crystalline properties, with particles diameters ranging from 6.21 to 12.56 nm. The obtained ternary composite N-C-dots/SgCN/ZnO showed noticeably higher photocatalytic effectiveness than its constituents' components. Additionally, N-C-dots/SgCN/ZnO demonstrated outstanding photocatalytic decomposition (93.49 %) of RhB dye under optimized conditions in only 35 min. Various dye degradation parameters like photocatalyst dose, dye concentration, pH of dye solution have been optimized for RhB degradation along with impacts of different scavengers. The results of capturing experiments revealed that h⁺, ^•O₂⁻ and ^•OH radicals are main components for photocatalytic breakdown of dye with O₂^{• −} rendering the major degradation, whereas ^•OH and h⁺ have minor involvement. N-C-dots/SgCN/ZnO demonstrated outstanding reusability up to five cycles by degrading 85.54 % RhB dye in 5th cycle in just 35 min. Additionally, only slight variations are observed in XRD pattern of freshly produced and recycled sample, indicating exceptional ternary composite stability.