Carbon Nanotube And Titanium Dioxide Supported Pt-based Catalyst And Their Electrocatalytic Oxidation Of Small Organic Molecule

As a new and promising power source, due to its high energy conversion density, inexpensive fuel and relatively quick start-up, and so on, the fuel cells using small organic molecule as fuel is widely employed in many fields. The development of catalyst is one of the core content in the fuel cells research. At present, platinium and platinium-based noble metal catalysts are used as electrocatalysts most frequently in small organic molecule fuel cells. However, the most significant barriers for the commercialization of small organic molecule fuel cells are the high cost, relative low catalytic acitivity and poor long-time stability of the noble metal electrocatalysts. Therefore, how to synthesize noble metal nanoparticles with small particle sizes, high dispersivity and how to further reduce the costs, improve Pt utilization becomes an important proposition in small organic molecule fuel cells.Herein, from the viewpoint of alloy composition and supporting materials, small particle sizes and high dispersion of Pt-M (Ir, Ru) and Pt catalysts were prepared by electrochemical deposition method, liquid impregnation reduction method and microwave assisted ethylene glycol reduction method, respectively. In addition, the electrocatalitic activity of the obtained electrocatalysts towards the electro-oxidation of glucose or methanol has been systematically studied. The main research work in this dissertation are carried out as following aspects:1. PtxIry nanoparticles with different compositions such as Pt3Ir1, Pt1Ir1, and Pt1ir3and Pt nanoparticles were deposited on CNTs surface by electrochemical deposition method and adjusting the molar ratio of the Pt and Ir precursors in the deposition bath solution. The morphology of the catalysts were investigated by transmission electron microscopic (TEM). The results shown that the average particle diameter of the noble metal nanoparticles is4.0±0.5nm. The electrocatalytic performance of the PtxIry/CNTs and Pt/CNTs catalysts towards glucose oxidation were investigated by cyclic voltammetry (CV) and chronoampermetry (CA). The results shown that all of the PtxIry/CNTs nanohybrids exhibited better electrocatalytic activity for glucose oxidation comparing that of Pt/CNTs nanohybrids, and the Pt1Ir1/CNTs nanohybrids have the best electrocatalytic performance.2. Taking carboxymethylcellulose sodium (CMC) surface-modified CNTs to prepared carboxymethylcellulose functionalized CNTs (CNTs-CMC) supporter, PtRu/CNTs-CMC nanohybrids were successfully obtained by liquid impregnation reduction method. The CNTs-CMC was charaterized by fourier transform infrared spectroscopy (FTIR) and raman (Raman) spectroscopy. The micrograph of PtRu/CNTs-CMC and their electrocatalytic properties for methanol oxidation were investigated by TEM and CV. The results shown that CMC fuctionalization process of CNTs does not damage the structure of CNTs, the average particle diameter of PtRu nanoparticles is3.5±0.5nm with a well dispersivity. Comparing the untreated CNTs supporting PtRu nanoparticles, PtRu/CNTs-CMC catalysts have a higher electrocatalytic activity and better long-term stability towards methanol electro-oxidation.3. The N-doped nanoparticle TiO2(TiO2-xNx) were prepared by sol-gel method, and using them as supporting materials, Pt/TiO2-xNx nanohybrids were synthesized by microwave assisted ethylene glycol reduction method. The micrograph and crystal structure of the Pt/TiO2-xNx were characterized. The results shown that the TiO2-xNx was a typical anatase crystal and Pt nanoparticles were highly dispersed on them with small particle sizes. The electrocatalytic properties of Pt/TiO2-xNx catalysts for methanol oxidation were investigated by CV and CA, respectively. The results shown that Pt/TiO2-xNx catalysts have a higher electrocatalytic activity and long-term stability towards methanol oxidation comparing that of Pt/TiO2nanohybrids.