Synthesis and evaluation of bifunctional reforming-shift composite catalysts on metal foams for methanol steam reforming with reduced CO production

This study investigates a strategy to reduce carbon monoxide (CO) content in the product gas from methanol steam reforming, a critical challenge since CO acts as a poison for fuel cell catalysts. To achieve this, bifunctional catalysts were developed on metallic foams. Bifunctional catalysts consisting of a leading layer of reforming catalyst composed of Cu/Zn/Zr oxides, followed by a low temperature water-gas shift (LTS) catalyst layer composed of Cu/Zn oxides, were synthesized over copper and nickel foams that were precoated with a thin layer of Al 2 O 3 . The effects of foam material, catalyst loading, share of LTS layer, reactor temperature, feed space velocity and steam to carbon ratio were studied on the performance of the catalyst in a microreactor system regarding methanol conversion, specific hydrogen (H 2 ) production rate and CO content of the product gas. The bifunctionalization approach proved highly effective, achieving over 70 % reduction in CO production, corresponding to a CO content in the product gas of less than 0.4 vol%, accompanied by no significant loss in methanol conversion. The bifunctional catalyst exhibited superior activity at lower temperatures, enhanced long term performance and higher specific H 2 production compared to similar studies on mono-functional reforming catalysts. It may be considered as a step forward in portable H 2 generator systems via steam reforming of methanol, with a more compact size and less CO production. • Methanol reforming catalyst is coated on nickel and copper foams with strong bonding, as a promising alternative for micro-channel reactors. • More than 70 % reduction in CO production in methanol reforming reaction is achieved via implementation of a low temperature shift catalyst layer following the upstream layer of reforming catalyst on metallic foams. • A highly active methanol reforming catalyst is obtained on metallic foams that can convert more than 95 % of methanol feed at relatively low temperature of 280°C and space velocity of 3000 hr −1 . • The space time yield of hydrogen from methanol reforming on these bifunctional composite catalysts reached to 1.5litre Hydrogen per milliliter of catalyst bed per hour.