Preparation of Anodes for DMFC by Co-Sputtering of Platinum and Ruthenium

Abstract

Anodes used for direct methanol fuel cells (DMFCs) were fabricated by magnetron sputtering process. A house-made plasma sputtering system was used to deposit Pt and PtRu onto un-catalyzed gas diffusion layers (GDLs) at different radio frequency (RF) powers and sputtering-gas pressures. The thin film catalyst layers were characterized by X-ray diffraction, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy. The sputtered anodes were assembled in custom-made membrane electrode assemblies (MEAs) with a commercial cathode and the electrical performance of the single cell were tested under passive methanol supply, ambient temperature and air-breathing conditions. The electrochemical performance of the anodes prepared with PtRu alloy was compared with a reference anode sputtered with Pt only. X-ray diffraction and X-ray photoelectron spectroscopy revealed that platinum and ruthenium existed as a form of alloy. The cell polarization measurements showed that all the PtRu alloy catalysts had better electrochemical performance than the Pt1 catalyst, and the Pt0.43Ru0.57 catalyst achieved the best performance.