Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
Nanoscale. 2012 Feb 7;4(3):1010-5. doi: 10.1039/c2nr11689h. Epub 2012 Jan 5.
Water-soluble carbon nanoparticles were prepared by refluxing natural gas soot in concentrated nitric acid. The surface of the resulting nanoparticles was found to be decorated with a variety of oxygenated species, as suggested by spectroscopic measurements. Back potentiometric titration of the nanoparticles was employed to quantify the coverage of carboxylic, lactonic, and phenolic moieties on the particle surface by taking advantage of their vast difference of acidity (pK(a)). The results were largely consistent with those reported in previous studies with other carbonaceous (nano)materials. Additionally, the presence of ortho- and para-quinone moieties on the nanoparticle surface was confirmed by selective labelling with o-phenylenediamine, as manifested in X-ray photoelectron spectroscopy, photoluminescence, and electrochemical measurements. The results further supported the arguments that the surface functional moieties that were analogous to 9,10-phenanthrenequinone were responsible for the unique photoluminescence of the nanoparticles and the emission might be regulated by surface charge state, as facilitated by the conjugated graphitic core matrix.
通过回流天然气烟尘于浓硝酸中制备了水溶性碳纳米粒子。通过光谱测量发现，所得纳米粒子的表面被各种含氧物种所修饰。通过背电位滴定纳米粒子，利用其酸度（pKa）的巨大差异，定量地确定了颗粒表面羧酸、内酯和酚基部分的覆盖率。结果与先前用其他碳质（纳米）材料进行的研究报告的结果基本一致。此外，通过邻苯二胺的选择性标记，证实了纳米粒子表面存在邻醌和对醌部分，这表现在 X 射线光电子能谱、光致发光和电化学测量中。结果进一步支持了以下论点，即类似于 9,10-菲醌的表面官能团负责纳米粒子独特的光致发光，并且通过共轭石墨核心基质的作用，发射可以通过表面电荷状态来调节。
