Synthesis of fluorescent carbon dots using bio-waste powder for photo-degradation of dyes: simulation and mechanistic study

Abstract

Biowaste-derived carbon quantum dots (CQDs) offer a wide range of applications, including bioimaging, drug degradation and manufacturing of sensors, photodetectors and photosensitisers. However, inaccurate measurements of their quantum confinement and valence/conduction band potentials complicate their application predictability. Herein, we report carbon dots synthesized hydrothermally (600 °C; 6 h) using sugarcane bagasse powder (SC-CQDs). These SC-CQDs were characterized through UV-visible, fluorescence, PXRD, XPS, DLS, FTIR, Raman, SEM, EDAX and TEM analyses. The obtained SC-CQDs resemble amorphous N-doped multilayer-nanographene-type spherical particles with a size of 9.09 nm and has a band gap of 2.46 eV (λ_abs: 298 nm) with –COOH/–OH functionalities. The quantum confinement and valence/conduction band potentials were estimated using Brus-Kayanuma quantum mechanical (BKQM) and virtual molecular dynamics (VMD) equations. These CQDs are potential candidates for sunlight-mediated methylene blue degradation in water within 36 min for up to four catalytic cycles.