An improved electrodeposition technique for preparing the CNTs supported catalyst for direct methanol fuel cell applications

• Main Authors: Yu-Ming Chang, 張育鳴
• Other Authors: Chuen-Horng Tsai
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/65165911809058576579

碩士 === 國立清華大學 === 工程與系統科學系 === 95 === In recent years, as a result of the fuel cell technology unprecedented development, the whole world attached great importance to fuel cell which was considered would be the “Power of Future”. Compared with the traditional electric power supply system, the fuel cell not only can enhance the energy efficiency and can reduce the environmental pollution. Among them, the direct methanol fuel cell (DMFC) was regarded as the best choice to solve the energy crisis in the future. But there were still various bottlenecks at present. This experiment expected the promotion for mass activity of anode catalyst and used platinum ruthenium binary alloy for suppression of carbon monoxide poisoning phenomenon. Then we could obtain the higher power density of cell. The ideal catalyst support need have large specific surface area, good electronic conductivity and stability under the environment of strong acid or alkali solution. Carbon nanotubes directly grown on carbon cloth were prominent materials as the catalyst supports that exhibited special properties which make them suitable for application in several technological areas. In our studies, we changed the partial oxygen at hydrophilical treatment, used two-sides carbon nanotubes and ultrasonic shaker in order to improve the electrodeposition efficiency, increase loading of electrocatalysts and mass activity. Further we would achieve electrodeposition optimization and reduce the cost and time. Electrochemical and physical characteristics of the prepared catalysts through cyclic voltammetry (CV), transmission electron microscopy (TEM), scanning electron microscopy (SEM), inductively coupled plasma-mass spectrometer (ICP-MS), X-ray powder diffraction (XPRD) and Fourier-transform infrared spectrometer (FTIR) were carried out. Finally we discussed methanol oxidation on these catalysts, efficiency, CO poisoning, mass activity, distribution and agglomeration. According to the experiment observations, the two-sides CNTs supported specimens which were potentiostatic deposited in the ultrasonic shaker after hydrophilical treatment under air flow conditions would obtain the largest forward peak current density because of the catalyst loadings increasing. TEM and XPRD analyses exhibited that well-dispersed Pt-Ru nanoparticles were observed on the CNTs and particle sizes of electrocatalysts were between 2 and 3 nanometers. But the results from SEM observation, the agglomerations were more serious. If increasing ruthenium concentration, the CO poisoning could decrease and the life of cell would be lengthening.