Composite Membrane Containing Pt-Ru Catalyst as Electrode for DMFC by Layer-By-Layer Techique

• Main Authors: Chuen-Rung Chen, 陳春榮
• Other Authors: Chieh-Hao Wan
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/25088702787130444131

碩士 === 明道大學 === 光電暨能源工程學系碩士班 === 103 === Abstract The performance and utilization of catalyst of direct methane fuel cell (DMFC) remains at a low level. Therefore, this research study the membrane electrode assembly formed by the self-assembly of polyallylamine hydrochloride (PAH) and polystyrene sulfonic acid sodium salt (PSS) containing the Pt-Ru catalyst to improve the reaction surface area and the output performance. The nanometer-sized catalyst layer formed by the PAH/PSS bi-layers is believed to improve the reaction surface area and the multi-layers structure is expected to extend the reaction area to three dimension, and thus enhances the overall reaction rate even with the low Pt-Ru catalyst loading (<0.1 mg cm-2) on both anode and cathode side. In addition, this design might oxidize the penetrating methanol while reducing cathode mixed potential effect. This will reduce the degree of cathode polarization, and thus enhancing the power density.Several methods and instruments are used for characterization of the obtained samples such as ultraviolet-visible spectroscopy (UV-Vis), AC impedance, cyclic voltammetry (CV), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Result shown that, samples with 10 layers containing 40%Pt50Ru50/C and 60%Pt50Ru50/C of PAH/PSS, thickness are 1.15um and 1.19um, the loading were 0.06 mg cm-2 and 0.08mg cm-2, have a great performance of PEMFC. The maximum output are 60.02mW cm-2 and 71.22mW cm-2 @(0.4V). However, a sample of 10 layers without adding any Pt50Ru50/C, the maximum output is 40.17mW cm-2 (@0.4V). This is because of the adding of 40Pt50Ru50/C or 60%Pt50Ru50/C catalyst in to solution of PAH, effectively the PAH/PSS self-assembled monolayers catalyst generated electron and proton transfer to an external circuit, respectively, with the proton exchange membrane and enhance the overall catalyst loadings. Therefore, to enhance the potential of the battery are respectively 39.5% and 49.7%, the power density are 49.4% and 77.3% (@0.4V). And due to this origin, samples of 10 layers containing 40%Pt50Ru50/C at PAH and 60%Pt50Ru50/C at PAH, the maximum output power of Direct Methanol Fuel Cell (DMFC) are 3.65 mW cm-2 and 4.08 mW cm-2 (@0.15V). The utilization rates of catalyst for the sample 10 layers : PAH/PSS- 40% Pt50Ru50/C at PEMFC and direct methanol fuel cell (DMFC) are 1285A g-1 Pt (@0.6V) and 385A g-1 Pt-Ru(@0.15V), while , the sample 10 layers : PAH/PSS- 60% Pt50Ru50/C at PEMFC and direct methanol fuel cell (DMFC) are 1106A g-1 Pt(@0.6V) and 335A g-1 Pt-Ru(@0.15V). Compared to the utilization rates for general process of catalyst are 2000A g-1 Pt (@0.6V) and 88A g-1 Pt-Ru(@0.15V), this new process method obtained a relatively high catalyst utilization. Keywords: membrane electrode assembly, nanometer-sized catalyst layer, self-assembly layer, multi-layers structure, DMFC.