Fabrication And Application Of Porous Carbon

The preparation and application of porous carbon have attracted great attention owing to their high surface area, good conductivity, physical and chemical stability, etc. They can be used in many critical areas, such as chemistry and chmical engineering, biomedical engineering, photoelectricy, electronics. Hence, we prepared various kinds of porous carbon, including inver opal carbon films and inverse opal carbon rods with macropores, nitrogen-doped carbon fibers with micropores, mesoporous nitrogen-doped carbon nanosheets, and we studied their properties, including cholesterol sensing properties, catalytic properties and charge storage properties. The detailed research content was as follows:(1) Carbon inverse opal films with macropores were prepared with SiO2 photonic crystal opal films as templates, and their oil sensing properties and cholesterol sensing properties were studied.(2) Three dimensional carbon inverse opal rods with macropores were prepared. Their cholesterol sensing properties were studied.(3) Three dimentional mesoporous nitrogen-doped carbon nanosheets were prepared, and the nanosheets were composed of iron containing carbon nanoparticles. Iron-magnesium hydroxide nanosheets were first synthesized, and reduced via a chemical vapor deposition(CVD) process. Carbon was grown around iron, with iron as catalyst, CH4 as carbon source. After magnesium removel, the mesoporous iron containing carbon nanosheets were obtained. They were doped with nitrogen by annealing at high temperature under the flow of ammonia. The resulting three dimentional mesoporous nitrogen-doped carbon nanosheets show outstanding oxygen reduction reaction(ORR) electrocatalytic activity, which was comparable with Pt based catalysts, and increased current density and more positive onset potential at very low cost.(4) Free-standing microporous nitrogen-doped carbon fibers were prepared by a facile template-free method. Cotton, which was composed of celluse fibers, was used as the precurser. Nitrogen-doped carbon fibers were prepared through the thermal treatment of cotton under the flow of argon and ammonia, where ammonia reacts with the carbon in cotton forming a microporous structure. Nitrogen-doped carbon fibers with micropores possess the unique features of high electrical conductivity, interconnected porous structure, and good mechanical flexibility. It provides multiple pathways for electron transport and facilitates the access of electrolyte ions into and from its internal surface, resulting in a high charge-discharge rate performance. The nitrogen doping process induces the pseudocapacitive effects. It can also improve the wettability, which is beneficial for enhanced contact between the electrode material and electrolyte. It is helpful for the electrolyte penetrating into the inside of the samples, leading to the efficient use of the internal surfaces. More importantly, the microporous nitrogen-doped carbon fibers were free-standing, which simplifies device fabrication processes, because there is no need for binder, conductive additives, or current collector. Compared to conventional supercapacitors, microporous nitrogen-doped carbon fibers reduce the overall weight and space in flexible carbon supercapacitors, widening their practical applications.