Design & Synthesis Of Carbon Nano-materials Based On CQDS And Their Catalytic Properties

In the years of study, carbon materials were mainly used as catalyst support. Take their directly as catalysts cover the major areas of the modern industry, agriculture and medicine are the new developments. The search and design of highly-effective carbon nano-materials is necessary. Due to the special optical and chemical properties, carbon quantum dots(CQDs) and modified CQDs have been widely used as catalysts in catalysis. In this paper, from the study of CQDs, we design and synthesize a series of doped CQDs and semi-carbonized carbohydrates which contain CQDs, then we explored their application in the hydrogen catalysis, oxygen reduction reaction and selective oxidation of hydrocarbon. The main contents are as follows:(1) CQDs with there different size(>10nm, 1-4nm and 5nm), were synthesized by a electrochemical etching method, and the as-prepared nanomaterials were characterized by TEM, HRTEM, UV-Vis、FT-IR、Raman and PL for morphology and propertity, and then these CQDs were used as catalysts for the aldol condensations, we found that the 5nm CQDs exhibited excellent hydrogen catalytic performance and stability under the visible light irradiation.(2) A combustion flame method was developed for the convenient and scalable fabrication of single- and dual-doped carbon quantum dots(CQDs)(N-CQDs, B-CQDs, P-CQDs, S-CQDs and dual-doped B,N-CQDs, P,N-CQDs, S,N-CQDs), and the nanomaterials were characterized by TEM、EDX、XPS、AFM、UV-Vis、FT-IR、Raman and PL for morphology and propertity, and then these doped CQDs were used as catalysts for the oxygen reduction reaction, we found that the dual-doped B,N-CQDs exhibited excellent catalytic performance and stability under the.(3) Three dimensionally macroporous carbon spheres(3DMPCS) were obtained by the carbonization(100-900°C) of carbohydrates(cellulose and glucose as precursors), and characterized by SEM、TEM、BET and Raman for morphology and propertity, and the obtained material was applied for the selective oxidation of cis-cyclooctene in the absence of solvent using TBHP as radical initiator and oxygen(in the air) as oxidant, and it showed good catalytic performance. Due to the existence of CQDs in the semi-carbonized materials, C-3DMPCS-500 and G-3DMPCS-600 showed the best catalytic performance the materials carbonized in other temperature.