落叶松木粉水热炭化制备碳量子点及其性能研究

Synthesis and Properties of Carbon Quantum Dots from Larch via Hydrothermal Carbonization

以落叶松木粉为原料,去离子水为溶剂,220℃条件下水热炭化制备出了具有荧光性能的水溶性碳量子点(CND),采用TEM、FT-IR、XPS、紫外分光光度计和荧光分光光度计对CND的粒径分布、结构特征及光学性质进行分析。结果表明:所制备的CND为球形结构,平均粒径20.35 nm,表面呈有序的晶格结构;CND主要含有C、O和N元素,其表面存在—OH、C=O及C—O等官能团,且证实了CND由芳环结构和大量的含氧官能团构成;CND样品在271 nm处有较弱的紫外吸收光谱,在350和440 nm处有特征激发和发射波长;随着CND溶液pH值的增加,溶液颜色逐渐加深,荧光强度逐渐减弱。TiO_2/CND复合体系具备良好的光催化活性,在可见光照射下能有效地催化降解目标产物四环素,可见光照下3 h的降解率可达93.6%。

Water soluble carbon quantum dots （CND） emitting green photoluminescence were synthesized by hydrothermal carbonization method （220℃） using larch as carbon source and deionized water as solvent. The particle size distribution, structure and optical properties of CND were characterized by transmission electron microscope（TEM）, Fourier transform infrared spectroscopy（FT-IR）, X-ray photoelectron spectroscopy（XPS）, ultraviolet spectrophotometer and fluorescence spectrophotometer. The results indicated that the obtained CND particles were uniform spherical with diameter of 20.35 nm and ordered lattice on surface. CND mainly contained C, O, N elements with -OH, C=O and C-O functional groups on the surface and the CNDs were formed with oxygen-containing group and aromatic ring structure. CND samples had a weaken absorption at 271 nm in the ultraviolet absorption spectrum and exhibited excitation wavelength-dependent fluorescence with the maximum emission and excitation at 350 and 440 nm. And the photoluminescence intensity was pH-dependent. The fluorescence intensity reduced and solution color became darker with the increasing of pH value of CND solution. TiO2/CND composite exhibited high photocatalytic activity for the degradation of tetracycline, and 93.6% degradation could be achieved after 3 h.