Synthesis and Characterization of Self-assembly, Surface-Modified, and Platinum Catalyst Supported Mesoporous Carbons and Their Application as Electrodecatalysts for DMFC/PEMFC Cathode

• Main Authors: Chien-Chang Chiang, 江建章
• Other Authors: Shang-Bin Liu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/7kuhdp

碩士 === 國立臺灣師範大學 === 化學系 === 96 === Facing the global crisis in shortage of fossil fuels and increasing environmental pollutions mainly from combustions of carbon-based fuels and abused emission of greenhouse gases, renewable energy-related R&D have becoming a demanding and challenging tasks. Among them, hydrogen fuel cells have received much attention and being considered as the ideal eco-friendly electrical energy conversion devices. The objectives of this research are to develop novel one-step synthesis route to fabricate nanostructured porous carbon materials and to utilize them as supports for noble metal (Pt) catalyst aiming at their practical applications in energy-related issues, such as hydrogen fuel storage and fuel cells. Owing to the high surface area, structural, thermal/hydrothermal, and mechanical stabilities, and adsorptive, electrical, and catalytic properties, carbon mesoporous materials (CMMs) represent ideal electrodecatalyst supports for fuel cells and adsorption carriers for fuel storage devices. However, in view of the sophisticated procedures invoked for fabrication of CMMs, which were mostly synthesized by replication method using ordered mesoporous silica’s as templates, infiltrated by appropriate carbon precursors followed by thermal polymerization, carbonization, and subsequent removal of the silica framework with acid or base solution. Such a complex synthesis procedure not only is cost ineffective but also limits practical commercial applications of CMMs. A facile method to fabricate CMMs is by crosslinking phenolic resins in the presence of a self-assembled block-copolymer surfactant template, followed by pyrolysis of the organic precursors (carbon source) and carbonization to obtain the self-assembled carbon materials (SCMs). The SCMs so fabricated were found to possess high surface area, good electrical conductivity, and aboundant hydroxyl groups on the pore-wall surfaces, which facilitates surface functionalization and dispersion of metal catalysts in a controllable fashion. In this work, SCMs were first synthesized by organic-organic self-assembly at different carbonization temperatures (350-850 oC), then, subjected to surface modification by organic silane reagent, 3-[2-(2-Aminoethylamino)ethylamino]propyltrimethoxysilane (TA), or by chemical treatments (H2O2 and H2SO4/HNO3). Subsequently, carbon-supported Pt catalysts (Pt-SCMs) were prepared via chemical reduction of H2PtCl6 by NaBH4 at room temperature. Related samples were characterized by a variety of different analytical and spectroscopic techniques. Furthermore, using the surface-functionalized Pt-SCMs as cathode electrodecatalyst, their electrocataytic activities during oxygen reduction reaction (ORR) were evaluated by cyclic voltammetry (CV) and compared to Pt-SCMs prepared by one-pot synthesis. The results obtained from this research should enhance not only our knowledge on direct fabrication and physicochemical properties of SCMs but also their practical applications as cathode electrocatalysts for proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC). Thus, the outcomes of this research should have some importance in academic as well as industrial R&D and applications.