Enhanced performance of a silicon microfabricated direct methanol fuel cell with PtRu catalysts supported on few-walled carbon nanotubes

摘要

Silicon micro fuel cells (Si-MFCs) are promising power supplies for microelectronic applications, however their development is still at early stages compared to the conventional proton exchange membrane fuel cells (PEMFCs). There are not many published reports on the durability of Si-MFCs and those available only projected the life-time of standard Vulcan based catalysts. However, the limited durability resulting from carbon corrosion is one of the crucial issues in fuel cells. In this study, Si-MFC with an integrated silicon nanograss diffusion layer is used for the direct methanol fuel cell investigations. The long-term (3-day) performance of PtRu catalysts supported on different carbon supports, namely Vulcan, Graphitized carbon nanofibers (GNFs) and Few-walled carbon nanotubes (FWCNTs), was studied. PtRu-FWCNTs and PtRu-GNFs exhibited respectively 471% (20.0 mW cm-2) and 274% (13.1 mW cm-2) power density enhancements compared to PtRu-Vulcan (3.5 mW cm-2). After 3-day durability measurements, power densitystayed at 72, 68 and 91% of the initial value, respectively for PtRu-FWCNTs, PtRu-GNFs and PtRu-Vulcan. To evaluate the influence of carbon supports as well as the distribution and the size of the nanoparticles on the overall performance of Si-MFCs, further characterizations with Raman, BET, XRD, SEM and TEM were performed.