Preparation, Coating and Patterning of Cu-Based Catalyst for Methanol Steam Reforming by Micro Fuel Reformer

Recent increase in need for a portable power source drives research on micro fuel cell and micro fuel reformer as a key component of micro power generation system. Various concept of reforming system is proposed and has been studied. As an attempt to develop wafer based micro reforming system, preparation, coating, and patterning of Cu-based catalysts for methanol steam reforming for micro fuel reformer are presented. Preliminary step to develop MEMS based micro fuel reformer is carried. As a first step, Cu-based catalysts are prepared by co-precipitation method. The effect of precipitation condition on physical characteristics and catalytic activity of the catalyst such as particle size, conversion rate and quality of coating on substrate are reported. And then coating processes of prepared catalysts on glass and silicon wafer are developed. A uniform and robust catalyst layer is obtained. The amount of coated catalyst on unit area of wafer is measured to be 5∼8 mg/cm², and the thickness of catalyst layer is about 50μm. By multiple coating processes, catalyst thickness can be controlled and up to 15mg/cm² is obtained that has good reactivity. After then, patterning of coated catalyst layer is reported. Deposited catalyst layer is patterned by way of lift-off process of PVA (Poly-Vinyl Alcohol), organic sacrificial layer, by heating the substrate instead of etching a sacrificial layer. With the results aforementioned on catalyst preparation, coating, and patterning, a prototype micro catalytic reactor for micro fuel reformer is fabricated with MEMS technology. The fabrication process includes wet anisotropic etching of photosensitive glass wafer, coating/patterning of catalyst and bonding of layers. Next step that is challenging part of development of micro reformer is to find a way to overcome the effect of heat loss that lowers the conversion rate of reforming process and to achieve fast kinetics for reduction of the device scale. We are pursuing further optimization of structural design to improve conversion efficiency and to obtain fast kinetics.