The Preparation Of Carbon Nanotubes Covered By Metal Or Metal Oxide And Their Electrochemical Characterization

The direct methanol fuel cell (DMFC) which is one of the most promising next-generation energy conversion device recives the widespread atthention. The commercial of DMFC is limited by the high prices of cathode and anode catalysts and their long-term stability. Carbon Nanotubes (CNTs) were modified with the ionic liquid-divinylbenzene copolymer and Hemin to disperse the Pt nanoparticles more uniform and smaller with less amount of Pt and explore the preparation of non-precious metal Oxygen Reduction Reaction (ORR) catalysts. The main content was summarized as following:1. Pt nanoparticles were deposited on the multi-walled carbon nanotubes (CNTs) with the assistance of the non-colvant functionalized with ionic liquid-divinylbenzene copolymer, and the thickness of the cross linker could be controlled easily. The physical characteristics are performed by X-ray diffraction(XRD), Transmission electron microscopy(TEM), the the Pt nanoparticles have a smaller diameter and narrow size distribution, dispersed on MWCNTs uniformly with the average diameter 3.3nm. The cyclic voltammetry tests reveal that the as-prepared Pt/PIL-DVB/MWCNT electrocatalysts show a high electrochemical surface area (ECSA) (67.46 m2/g) and a great current density (425.0 mA mg-1) for methanol oxidation than Pt/CNTs..2. The surface of carbon nanotubes was absorbed with the Heme by non-covalently and the functionalized carbon nanotubes was prepared for Pt/Heme-CNTs catalyst. The modified carbon nanotubes were characterized by Raman spectroscopy and the Pt nanoparticles were observed by Transmission electron microscopy (TEM). The catalyst shows a better methanol electrocatalytic oxidation than Pt/OCNTs and a better oxygen electrocatalytic reduction than the commercial Pt/C.3. Using cerium ammonium nitrate as the oxidizing agent, the nitrogen-doped carbon nanotubes was coverd with cerium oxide by one-pot method. The elemental and morphology analysis of the catalyst was carried out by X-ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM). Compared with the commercial Pt/C catalyst, the CeO2/N-CNTs catalyst have the capacity of oxygen electrocatalytic reduction and a greater current density.