| 英文摘要
| We used a simple, fast, eco-friendly electrochemical strategy to prepare carbon nanodots (C dots) from histidine under alkaline conditions by applying a constant voltage of 10 V at room temperature without using any toxic chemicals and organic solvents. The effects of concentrations of histidine, pH, reaction time and sodium halides such as sodium chloride (NaCl), sodium bromide (NaBr), and sodium iodide (NaI) on the properties of as-prepared C dots were investigated. The optimal conditions to prepare C dots are 0.63 M histidine, pH 9.0 and 1 M sodium halides. This method has the advantages of low-cost, short reaction time, low energy and the photoluminescence (PL) is observable at any time. The formation rates of C dots synthesized by adding NaCl, NaBr and NaI (Cl-C dots, Br-C dots, I-C dots) was controlled through the differential nucleophilicity and leaving ability of sodium halides. The C dots prepared in presence of sodium halides exhibits high photostability at high concentrations of salts (0-3.0 M), different pH (3.0-11.0) and 1 h irradiation. Compared to C dots, Cl- or Br-C dots, I-C dots shows high selectivity and sensitivity toward the Cu2+ ions. Cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of metal-ligand complexes between Cu2+ ions and I-C-dots and the charge transfer leading to the PL quenching of I-C dots. The I-C dots allowed detection of Cu2+ ions, with a limit of detection (LOD) and a linear range of 0.22 μM and 0.3-3.0 μM, respectively. Furthermore, the practicality of I-C dots toward the detection of Cu2+ ions in real samples such as tap water, lake water and seawater was demonstrated. Having advantages such as short preparation time, high photostability, high selectivity and sensitivity, I-C dots are holding great potential for the detection of Cu2+ ions in complex matrices such as living cells and blood. |
