The new carbon nano-materials and its function of absorbing a direct methanol fuel cell application, analysis

　　Title: The new carbon nano-materials and its function of absorbing a direct methanol fuel cell application, analysis
　　Author: Li Yongjie
　　Degree-granting units: Lanzhou University
　　Keywords: Carbon nanotubes;; graphite oxide;; graphene;; silicon carbide;; Ni-Co-P alloy;; Ni nanoparticles;; Pt nanoparticles;; plating
　　Abstract:
　　The doctoral thesis in previous research, based on the use of chemical plating and liquid reduction, prepared Ni 1-x-Co x-P / multi-walled carbon nanotubes (Ni1-xCox/MWNTs), Nickel - Cobalt - P / silicon carbide (Ni-Co-P/SiC), nickel / chemical Rare earth magnets conversion of graphene (Ni / CCG), platinum / chemical conversion of graphene (Pt / CCG), platinum / multi-walled carbon nanotubes (Pt / MWNTs ) five new nano-materials; scanning electron microscopy (SEM), transmission electron microscopy (TEM) study of the morphology of these materials: X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X ray spectrometer (EDX) analysis of the lattice structure of these materials and elements; using a vibrating sample magnetometer (VSM), vector network analyzer of Ni1-xCoxP/MWNTs, Ni-Co-P/SiC and Ni / CCG magnetic, absorbing character; electrochemical method of Pt / CCG, Pt / MWNTs as a direct methanol fuel cell catalytic performance. The study includes:
　　1 multi-walled carbon nanotubes will be boiling with concentrated nitric acid, SnCl2, PdCl2 solution after activation of sensitization, since the distribution of the Ni-Co plating solution (Ni: Co = 1:3,1:1,3:1) in plating, get Ni1-xCoxP/MWNTs composite (x = 0.75,0.50,0.25, Ni1-xCoxP size distribution in the 8-18nm). XRD data show that with the Ni1-xCoxP MWNTs composite nanoparticles in a lattice structure after heat treatment to irregular point-like structures scattered in the outer wall of MWNTs. Magnetic properties of the sample measurement results that the prepared materials, coercivity and magnetization are with the Ni content increases. In the 2-18GHz frequency range, Ni1-xCoxP/MWNTs- the complex permittivity of a mixture of paraffin with the value of the increase in Ni content decreases; complex permeability only slightly increased. With the reduction of Ni content, the prepared materials electromagnetic wave reflection loss peak moves to the low frequency region, and when x = 0.75 and the matching thickness of 2.5mm, the largest occurring at 7.75GHz reflection loss-26.84dB.
　　2 using two-step activation method of plating technology, the SiC into the Pd activated with the Ni-Co from the solution to get Ni-Co-P/SiC composite plating. Morphology and structure analysis shows that Ni-Co-P particles uniformly good, and after the heat treatment by the composition of α-Co and Ni3P. Analysis of magnetic properties and microwave absorption test results show that, Ni-Co-P/SiC saturation magnetization and coercive force are relatively low, with high dielectric constant value of magnetic loss microwave absorption properties of the material has some contribution. Electromagnetic wave reflection loss measurements showed that when the initial solution of http://www.chinamagnets.biz/ Ni-Co atomic ratio of 1.5, the maximum reflection loss value is-32dB, then the matching thickness of 2.5mm, a frequency of 6.30GHz.
　　3 using hydrazine reduction method, with NiSO4, graphite oxide (Graphite Oxide, GO), respectively, as the carrier of Ni and carbon sources, prepared Ni / CCG composites. The results show that the magnetic properties of the prepared Ni / CCG showing a ferromagnetic nature, is expected to absorbing materials, and other aspects of the field of magnetic recording applications.
　　4 oxidation of the graphite GO, and then in the chloroplatinic acid - ethylene glycol - water solution system restore to get Pt / CCG composite; in a similar way to the MWCNT processed by Pt / MWCNT composites. Then compare the two materials as a direct methanol fuel cell catalytic performance to prove that Pt / CCG and Pt / MWCNT, respectively, the electrochemical active surface area is 36.27m2 / g and 33.43m2 / g. Pt / CCG CO poisoning have more patience, showing enhanced electro-catalytic oxidation of methanol activity.
　　Degree Year: 2010