High Performance Methanol Reforming Type Micro Fuel Cell (J. Power Sources, 2007, 2010, 2013, MNF 2008, 2009, 2010, Electrochim. Acta 2012, J. Electrochem. Soc. 2012 )
In the present study, a novel micro-channel methanol reformer with a finger-shaped groove structure w as successfully demonstrated to enhance the methanol conversion rate and the hydrogen yield. By introducing a centrifugal technique, a porous and gradient distribution of the catalyst layer thickness can be obtained inside the micro-channels so as to force the methanol steam to react sufficiently with high surface area catalysts. As the ratio of binder to catalysts varied from 60 to 0, the methanol conversion rate, hydrogen selectivity and hydrogen yield of the micro-methanol reformer at 250 oC can approach ~100%, 92% and 1.56×10-5 mole min-1, respectively. Moreover, a high performance output can still be obtained even at 200 oC, which is superior to our previous studies. Furthermore, a silicon-based micro proton exchange membrane fuel cell (μ-PEMFC) is introduced, carrying out a highly efficient catalyst utilization and cell performance. The design integrates micro/nano-machining techniques to enhance reaction area, the micro-patterned reaction chamber to create more three-phase zones and reduce fuel diffusion impedance, and the micro-interlocks to solidify interfacial strength and reduce ohmic impedance. The best cell output in this study can approach 26 mW cm-2 only with a Pt catalyst loading of 0.69 mg cm-2.