Catalyst preparation for fabrication of a MEMS fuel reformer

Fabrication procedures for a micro fuel reformer including catalyst preparation, coating, and patterning on a wafer are described. Cu/ZnO catalyst was selected for the steam reforming of methanol. The catalysts were prepared by three different procedures according to the precipitation sequence and temperature. The effect of precipitation conditions on the catalyst characteristics was investigated by BET, XRD and SEM analysis. Catalytic activity and coating quality were tested to find the optimum precipitation condition for the uniform and crack-free catalyst layer on a wafer. For coating purpose, the prepared catalyst was ground by ball-mill into powder and mixed with binder in the deionized water. Simultaneous precipitation of catalyst and binder on the wafer produced a catalyst layer that is uniform and rigidly found to the wafer surface. The amount of the coated catalyst was 5–8 mg/cm2 and the thickness was 30 μm. By repetition of the coating procedure, the catalyst mass up to 15 mg/cm2 was obtained with increased reactivity. Patterned catalyst layer was obtained by a novel lift-off process of the PVA sacrificial layer. The process consists of the PVA decomposition by heating instead of etching the wafer. A micro fuel reformer was fabricated using a typical lithography procedure including catalyst coating and patterning process and its performance was measured. The catalyst-coated micro fuel reformer had higher performances than the packed-bed reactor.