Preparation And Application Of Nanosized Carbon Materials/Carbon Foams Composite

Nanosized carbon materials (NCMs) attract a growing interest due to their specific characteristics. NCMs, however, may have problems in practical applications. The preparation of NCMs-containing monolithic composites is considered as the best way to solve these problems. However, the existed synthetic strategy is complicated multiple step synthetic procedures with monotone products. In the present thesis several kinds of NCMs-containing monolithic composites are obtained via in situ catalyst loaded method with carbon foam (CF) as substrate. Some progresses in the thesis are briefly summarized as follows:With in situ catalyst loaded method by introducing Ni(NO3)2 into polyamic acid (PAA), CFs made of carbon nanocapsules(CNCs) with a high degree of graphitization are produced with polyurethane (PU) foam as template. The foam-like monolith consists of open cells. The cell walls are made of graphitized CNCs with diameters of around 30-80 nm which are embedded in the amorphous carbon. The mass ratio of the CNCs in CNC/CF materials is about 85 wt.%. The N2 sorption curve shows typical characteristic of mesopore with a narrow size distribution of about 3.8 nm.Carbon nanofibers (CNFs)/CF composite that is made by growing CNFs on the surface of CF using the in situ loaded Ni particles formed during the carbonization of Ni/CF as catalysts was synthesized. Compared with the traditional incipient impregnation method, the in situ catalyst loaded'method is a facile and environment-friendly process. It is shown that, after the CVD process, the CF substrates are compactly covered by CNFs with external diameters and lengths of ca. 50-100 nm and several tens microns, respectively. The catalytic activity of obtained CNFs/CF monolithic composite toward oxidative dehydrogenation of ethylbenzene to styrene is tested. The composite exhibits a steady-state ethylbenzene conversion of 26% and the selectivity to styrene is 73% which is higher than that of the crushed CNFs/CF (69%). The outstanding catalytic performance could be partly attributed to the unique structure of CF.CNFs/CF are also prepared from coal liquefaction residue by a procedure involving supercritical foaming or template method, oxidization, carbonization and CVD treatment.Carbon belts (CBs)/CF have been fabricated by modifying the procedure of preparation of CNFs/CF. After the CVD process, the CF substrates are covered by CBs with thickness of 50μm. The dimensions of the CBs are evaluated to be hundreds of micrometers in length, several micrometers in width and tens of nanometers in thickness. The CBs consist of CNFs with relatively low degree of graphitization which array with an orientation roughly parallel to the longitudinal axis of the CBs. The effect of the mass ratio of Ni to PAA, the carbonization atmosphere and the sulfur species in CVD on the formation of CBs is discussed.CFs consisted of ordered mesoporous carbon (OMCs), which is a hierarchically porous carbon monolith with interconnected tunable macropores, was successfully prepared using hard template or soft template method. The zeolite/CF composites were prepared by carbonizing PU foam impregnated with a mixture of PAA and T-type zeolite. It has been found that T-type zeolites are anchored on the cell walls of the CF with their structure remain unchanged.