Micromachined methanol reformer for portable PEM fuel cells

Abstract

Fabrication procedures for a micromethanol reformer including catalyst preparation, coating, and patterning on a wafer are described. Cu-based catalyst was prepared by coprecipitation method. The effects of precipitation conditions on the catalytic activity and adhesion of coated catalyst on the substrate were tested to find the optimum precipitation condition. For coating purposes, the prepared catalyst was ground into powder and mixed with binder in the solvent. Simultaneous precipitation of catalyst and binder on the wafer produced catalyst layer that is uniform and rigidly found to the wafer surface. The amount of coated catalyst on the wafer was 5-8 mg/cm(2) with a thickness of 30 mu m. By repetition of coating procedure, catalyst mass up to 15 mg/cm(2) was obtained with increased reactivity. Patterned catalyst layer was obtained by novel lift-off process of polyvinyl alcohol sacrificial layer A micromethanol reformer was fabricated using a typical lithography procedure including catalyst coating and patterning process. Typical methanol conversion was higher than the conventional packed bed reactor.