Low Temperature Synthesis of Carbon Quantum Dots as Surfactants for Pickering Emulsions

Carbon quantum dots (CQDs) have attracted significant attention in both academic research and industrial applications due to their outstanding optical, electrical, and chemical properties. However, their complex synthesis and low yield limit large-scale industrial applications. This study developed a rapid and efficient synthesis method for CQDs based on the nonenzymatic browning reaction of ascorbic acid and citric acid. CQDs synthesized at relatively low temperatures (90–160 °C) exhibited sizes ranging from 1.5 ± 1.3 to 3.3 ± 2.9 nm and thicknesses between 0.5 and 3.2 ± 0.3 nm, achieving a maximum product yield of 19.85 ± 0.67 wt % at 150 °C for 4 h. CQDs exhibited a robust emulsifying performance across multiple oil phases, maintaining stable emulsions for 7 days. This work provides a novel strategy for the scalable synthesis and industrial application of CQDs.