METHOD FOR PRODUCING A PREFERENTIAL OXIDATION CATALYST

摘要

Disclosed is a hydrogen generation process for use with fuel cells which includes a preferential oxidation step to reduce the concentration of carbon monoxide. The preferential oxidation step includes contacting a fuel stream comprising hydrogen and carbon monoxide in the presence of an oxygen at a preferential oxidation temperature of between 70 DEG and 160 DEG C with preferential oxidation catalyst for reducing the concentration of carbon monoxide to produce a treated fuel gas stream comprising less than 50 ppm-vol carbon monoxide. The preferential oxidation catalyst comprises ruthenium metal dispersed on a shaped alumina carrier, wherein at least 60 percent of the ruthenium metal is present in a band extending from the surface towards the center and having a width of 50 percent of the distance from the surface to the center of the shaped alumina carrier. Superior performance at low preferential oxidation temperatures below 130 DEG C was observed when the band comprised 50 percent of the alumina carrier and contained at least 60 percent of the ruthenium metal. The preferential oxidation catalyst may be employed to reduce carbon monoxide in fuel gas streams supplied to fuel cells wherein carbon monoxide will poison the active noble metal membrane and higher preferential oxidation temperatures may reduce the hydrogen content of the gas stream.