Assessment of biomass derived N-C-dots decoration on photocatalytic efficiency of S-g-C3N4/g-C3N4 homojunction

Abstract

Herein, ginger-derived N-doped carbon dots (N-C-dots) using pyrolysis method are decorated over in-situ fabricated n/n homojunction i.e., S-g-C₃N₄/g-C₃N₄ (SgCN/gCN) by hydrothermal approach for photocatalytic breakdown of rhodamine B (RhB) dye. The obtained N-C-dots exhibited crystalline nature having quasi spherical particle with sizes in 2.36–8.51 nm range, whereas SgCN/gCN has a layered morphology. The resulting ternary composite N-C-dots/SgCN/gCN demonstrated significantly greater photocatalytic efficacy than the individual components under UV-light. Under optimal circumstances i.e., pH = 3, dye concentration 5 ppm, photocatalyst dosage 0.06 g, N-C-dots/SgCN/gCN displayed excellent photocatalytic degradation of RhB dye (99.68 %) in only 10 min exposure to UV-irradiations. Capture experiments revealed that O₂^•− radical ions are primary reactive components for dye degradation while ^•OH and h⁺ have relatively minor contribution. The findings of capture studies were employed to propose probable photocatalytic dye decomposition route. Additionally, N-C-dots/SgCN/gCN showed excellent stability and good reusability up to 5 cycles with just a small drop in photocatalyst efficiency.