Deposition of Pt and Pt-Ru Nanoparticles on RuO2.xH2O Using Microwave Method for Direct Methanol Fuel Cells

Abstract

Abstract-An easy and quick way to deposit platinum (Pt)-ruthenium (Ru) alloy nanoparticles on hydrous ruthenium dioxide (RuO 2 .xH 2 O) as supporting materials was developed using microwave heating. The x-ray diffractometer and selective area electron diffraction (SAED) showed that Pt-Ru alloy was formed. The transmission electron microscopic (TEM) image showed that average size of Pt-Ru was about 2-3 nm. Cyclic voltammogram of a Pt-Ru/RuO 2 .xH 2 O electrode showed high specific capacitance due to the protonation reaction in the acidic electrolyte and catalytic activity, including the methanol oxidation. The new Pt-Ru/RuO 2 .xH 2 O can be used as anode electrode materials in monolithic fuel cell/supercapacitor hybrid energy devices, since it has already been demonstrated that a layer of RuO 2 .xH 2 O sandwiched between anode catalytic layer and a membrane improved the dynamic response of the direct methanol fuel cell (DMFC).Index Terms-Direct methanol fuel cell, super capacitor, hybrid, and RuO 2 .xH 2 O. I. INTRODUCTIONAmong the different types of fuel cell, the direct methanol fuel cell (DMFC) has particular advantages including ease operation, miniaturization and a simple fuel supply system [1]- [4]. In recent years, research interest in high power DMFC modules has increased. This kind of power module is mainly designed for applications where high power mobile electrical energy sources are required (i.e. electrical vehicles and portable electronics devices) [1], [2], [5], [6]. Nevertheless, many problems relating to the operation of DMFCs under realistic operating conditions (i.e. dynamic operating conditions), have not been solved [7]- [11]. Therefore, all available fuel cell systems currently employ a large bank of battery or electrochemical (EC) capacitor between the electric load and fuel cell to buffer transient load demands [12], [13]. This buffer system brings the difficulties of further limiting the miniaturization of the fuel cell power system and lowering system cost. Therefore, it is attractive to be able to operate the DMFC system reliably and effectively without such a buffer system or at least with a much smaller one in order to widen the market for DMFC.The poor performance of the DMFC is due to the poor kinetics of the anode reaction and fuel crossover [3], [14], [15]. Compared with losses in proton exchange membrane fuel cell (PEMFC) such as activation polarization, electrolyte ionic resistance, electrode ionic/ohmic resistance, DMFC also Manuscript received November 10, 2015; revised March 10, 2016. This work was supported in part by the U.S. Army CERDEC.J. P. Zheng and V. Tiwari are with the Department of Electrical and Computer Engineering, Florida State University, Tallahassee, FL, USA (e-mail: zheng@eng.fsu.edu, tiwarvi@eng.fsu.edu).includes larger anode activation overpotential and fuel crossover. The mass transport loss in DMFC is also much greater than that in PEMFC. The low catalyst utilization is due to the fact that only a relatively small amount of the catalyst surface materials ...