Investigation of the DMFC gas diffusion electrode of the polyaniline/graphene oxide tube composite

• Main Authors: Kuang-Wei Lin, 林洸緯
• Other Authors: Chi-Wen Lin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/61321526655447210374

碩士 === 國立雲林科技大學 === 化學工程與材料工程系碩士班 === 102 === This study aims the preparation polyaniline / graphene oxide nanotubes (PANI / GO-Tube) through the polymerization of aniline in presence the graphite oxide to modify gas diffusion layer for improving direct methanol fuel cell performance under the a high concentrations of methanol. First, fourier transform infrared spectra (FT-IR) confirmed polyaniline and graphene oxide formula features functional groups, and thus verifies the coexistence of PANI and GO in the produced nanotubes. Surface electron microscopy (SEM) and Transmission electron microscopy (TEM) analysis PANI / GO surface morphology and the situation inside the material, from the results, the preparation of PANI / GO-Tube with nanoscale hollow tube structure with an outer diameter 120nm inner diameter of 15nm. Subsequently, the basic nature of the PANI / GO-Tube modifying gas diffusion layer is explored. First, the contact angle test results indicate that the PANI/GO-Tube exhibits the highest hydrophilic compare to pristine GDL and PANI-Tube. Second, Mercury Intrusion Porosimetry analyzes pore size distribution, which found PANI / GO-Tube increased significantly large pore distribution of the modified diffusion layer. For Electrochemical analysis, cyclic voltammetry tests indicate that gas diffusion layer modified PANI/GO-tube can improve the catalytic ability of methanol. This enhanced performance is mainly attributed to the π–π stacking effect between polyaniline and grapheme oxide. And then by measuring the methanol permeation current, it can prove that diffusion electrode modified PANI / GO-Tube can reduce methanol permeability of the membrane electrode group. Electrochemical impedance analysis PANI / GO-Tube influence on mass transfer resistance and charge transfer resistance of the gas diffusion layer. Finally, the gas diffusion layer assembles a single cell. when PANI / GO-Tube diffusion electrodes operate at a high concentration of methanol, the power value of the gas diffusion layer compared to unmodified significant advantage. For example methanol concentration of 8M, PANI / GO-Tube single cell of the modified maximum power (54mwcm-2) compared to unmodified gas diffusion layer (15mwcm-2) than 3.6 times. For long-term stability test, the maximum power value of PANI/GO-tube electrode decreased from 55.8mwcm-2 to 52.2mwcm-2, which decline was 6%. Compared to modified gas diffusion layer, the maximum power value of pristine gas diffusion layer decreased from 49.6mwcm-2 to 34mwcm-2, which decline was 31%. This two electrodes decline significantly reduce the number of the former.