Rapid Synthesis of N, S‐Co‐Doped Fluorescent Carbon Dots From <i>Eriocaulon buergerianum</i> as a Selective Probe for Pd ²⁺ Detection

In this study, N, S-co-doped carbon dots (N, S-CDs) with high fluorescence quantum yield (36.6%) were successfully prepared by H₂O₂ mediated self-exothermic reaction under alkaline conditions using Eriocaulon buergerianum as a carbon source and ethylenediamine (EDA) as a surface modifier. The synthesized N, S-CDs have a uniform size distribution (1-4.5 nm) and exhibit double emission peaks (389 and 410 nm) under 310 nm excitation. It was found that the N, S-CDs exhibited highly selective and sensitive fluorescence response to Pd²⁺ in aqueous solution, and the fluorescence intensity decreased significantly with the increase of Pd²⁺ concentration (0.05-3.5 μg mL^-1). The detection limit was as low as 5.51 ng mL^-1, and the relative standard deviation (RSD) was 1.56%. The study of quenching mechanism showed that the mixed static-dynamic quenching interaction between Pd²⁺ and N, S-CDs resulted in fluorescence quenching. In addition, the probe showed good detection performance in lake water, river water, and synthetic water samples, and the recovery rate met the analysis requirements. This study not only provides a green and economical fluorescence sensing strategy for the efficient detection of Pd²⁺ but also opens up a new way for the application of natural plant resources in the preparation of functional nanomaterials.