Carbon Replicas of Porous Concrete Obtained by Chemical Vapor Deposition—Some Aspects of the Synthesis Mechanism

In this contribution, the template assisted synthesis of porous carbons by chemical vapor deposition in porous concrete templates has been described for the first time. Porous concrete made templates can be obtained in almost any geometrical shape and are therefore attractive templates to prepare porous carbon monoliths. The carbon deposition process in porous concrete follows a three-stage-course consisting in an initial period, a period of fast carbon deposition and a period of slow carbon deposition. The carbon growth within the template pores occurs obviously plug-like from the inner to the outer sphere. Any continuous covering of the template pore walls by carbon could not be observed. In difference to porous concrete, the carbon deposition in silica gel is strongly accompanied by mass transfer limitations. For porous concrete, such strong effect has not been observed obviously due to its hierarchical pore system. The template materials have been loaded with carbon by chemical vapor deposition in a flow reactor. The process of the template pore filling has been characterized by the time dependence of the template mass gain. The materials have been characterized by means of X-ray tomography and nitrogen adsorption at 77 K, respectively.

软木塞基碳量子点的水热合成及其生物相融荧光成像应用

以废弃酒瓶软木塞为原料,采用低成本、简单的水热方法合成碳量子点。通过TEM、FTIR、Raman、UV-Vis、PL光谱对碳量子点的结构和光学性能进行分析表征。结果表明,碳量子点的平均直径为6.2±2.7 nm,PL激发谱和碳量子点表面的官能团有关。用硫酸奎宁作为参考,碳量子点的量子效率为1.54%。将获得的碳量子点应用在骨髓间充质干细胞的细胞生物成像上,发现用碳量子点处理后,骨髓间充质干细胞分别在320~380 nm、450~490 nm和450~490 nm范围显示绿色、黄色和红色荧光,表明了碳量子点在荧光成像领域具有潜在的应用价值。