Sustainable Solar-Driven Synthesis of High-Purity Carbon Quantum Dots from Corn Stover for Efficient H₂O₂ Production from Water

Abstract

We present a sustainable photocatalytic approach for synthesizing carbon quantum dots (CQDs) from renewable corn stover under simulated solar irradiation. In this process, hydrogen peroxide (H₂O₂) is spontaneously and continuously generated from water microdroplets. Naturally occurring ferrous (Fe²⁺) and other multivalent ions in the corn stover catalyze the decomposition of H₂O₂, producing highly reactive hydroxyl radicals (•OH) that drive the oxidation, decomposition, and condensation of organic molecules into CQDs. An oxygen-rich environment further facilitates the reaction. Compared to conventional methods, this approach enhances H₂O₂ utilization efficiency while minimizing excessive oxidation caused by high oxidizer dosages (e.g., H₂O₂, HNO₃). The resulting CQDs (4.6 ± 0.8 nm) exhibit intense blue fluorescence with a quantum yield of up to 20.1%. Structural characterization (XRD, FTIR, Raman, NMR, XPS) confirms their amorphous graphitic nature with nitrogen self-doping. Following centrifuge and dialysis purification, uniform CQDs with an average size of 3.1 ± 1.4 nm and high purity were obtained.