Synthesis And Electrochemical Application Of Heteroatom Doped Nanocarbon

Supereapacitor is a novel energy storing device, which has many excellent advantages,such as large power density, rapid charging ability, wide application temperature scope,long life, environmentally friendly and so on. Therefore, tremendous efforts have beendevoted to developing active electrode materials for supercapacitor applications. Fuel cellscan convert chemical energy into electric energy with high conversion efficiency, highpower density, quiet operation, and no pollution, which makes them one of the mostimportant energy conversion devices. Among various electrode materials and catalysts forORR, porous carbon materials have occupied a special place in the development due totheir high surface area and moderate cost. Templated carbon, a3D form of carbon atomswith hierarchical porous channels, has been considered as one of the most promisingelectrode materials to realize high-energy EDLCs in the past decades. Besides the structuraldesign, another way to improve the capacitance is to introduce the pseudocapacitance, suchas heteroatoms. Introducing heteroatoms (e.g., N, P, B, etc.), especially nitrogen, willimprove the carbonaceous electrode or ORR performance while maintaining the excellentintrinsic characteristics of carbonaceous materials.In this paper, NP-codoped mesoporous carbon fibers were successfully achieved bychemical polymerization method, hard template method and nanocasting method.NP-doped mesoporous graphene has been prepared by Hummer’s method, hard templatemethod and high temperature reduction. The structure, morphology and component of theas-synthesized materials were characterized by different analysis methods. The maincontents can be summarized as follows:(1)Three-dimensional rod-like and hierarchical mesoporous carbon material dopedwith nitrogen and phosphrus has been fabricated through a simple hydrothermalnanocasting method followed by carbonization with silicon dioxide as template, polyanilineas carbon precursor and triphenylphosphine as additive. The structure is composed ofmesopores in the interconnected nanorods.(2)The MCF electrode can achieve a relatively high capacitance of147.6Fg-1at acurrent density of0.05A g-1and excellent rate capability (99.6%retention at2A g-1) with superior cycle stability(86.5%retention after4000cycles) in7M KOH electrolyte. Thetwo-electrode supercapacitor delivers a high energy density of20.14Wh kg-1at a powerdensity of1647.67W kg-1operated in the voltage range of0—1V.(3)GO was prepared by Hummers method. NP-codoped mesoporous graphene wassynthesized by chemical reduction method and hard template method with graphene oxideas carbon source,1-Ethyl-3-methylimidazolium Dicyanamide as the nitrogen source,tetrabutylphosphonium bromide as the phosphrus source and SiO2as template. The BETsurface area of mesoporous graphene was increased as heteroatoms were doped.(4)The oxygen reduction reaction was studied by cyclic voltammetry and rotating diskelectrode. The results indicated that the electron transfer for ORR at doped mesoporousgraphene catalysts is found to be3.16. Compared with the commercial Pt/C, the N-MGexhibited better tolerance of cross-over effects and long-term stability in alkaline solution.