Preparation of Fluorescent Carbon-Based Dots from Waste Tire Pyrolysis

The pyrolysis of waste tire has been proposed as an alternative route to its recycling producing residual oils that can be used as fuels. In this work, a physicochemical process to obtain carbon-based dots (CBD) from carbon black (CBL) derivatives of tires is described. For this, the CBL was treated with different acids to produce CBL1 and CBL2 particles suspension. The pH of the suspension was adjusted to 5.6 to precipitate remaining impurities. Afterwards, the supernatant was ultra-centrifuged and the yellow pale solid, the purified CBD obtained by roto evaporation, was characterized by ultraviolet-visible spectrophotometer (UV-Vis), photoluminescence (PL) at 320-380 nm, high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared microscopy (mFTIR), and X-ray photoelectron spectroscopy (XPS). This material showed the typical excitation wavelength dependent emission and a PL quantum yield of 19.29% and was constituted by a well-defined spherical shaped and single sheets of “graphene quantum dots” with undefined shape, with potential applications in optoelectronic and fluorescence imaging devices.

废旧轮胎热解已被提出作为其回收利用的替代路径，可生成可用作燃料的残余油品。本研究阐述了一种从轮胎衍生炭黑（carbon black, CBL）制备碳基点（carbon-based dots, CBD）的物理化学方法。为此，研究人员采用不同酸处理CBL，制备得到CBL1与CBL2颗粒悬浮液，并将悬浮液pH值调至5.6以沉淀除去残留杂质。随后，取上清液进行超速离心，通过旋转蒸发得到纯化后的淡黄色固体（即CBD），并采用紫外-可见分光光度计（ultraviolet-visible spectrophotometer, UV-Vis）、320~380 nm波段光致发光（photoluminescence, PL）光谱、高分辨透射电子显微镜（high-resolution transmission electron microscopy, HRTEM）、扫描电子显微镜（scanning electron microscopy, SEM）、热重分析（thermogravimetric analysis, TGA）、能量色散X射线能谱（energy-dispersive X-ray spectroscopy, EDX）、傅里叶变换红外显微成像（Fourier transform infrared microscopy, mFTIR）以及X射线光电子能谱（X-ray photoelectron spectroscopy, XPS）对其进行表征。该材料展现出典型的激发波长依赖型发光特性，光致发光量子产率达19.29%，其结构由形貌规整的球形单元与无定形单层石墨烯量子片共同构成，在光电子器件与荧光成像设备中具备潜在应用价值。