Microfibrous entrapped ZnO-CaO/Al₂O₃ for high efficiency hydrogen production via methanol steam reforming

Sinter-locked microfibrous networks consisting of ∼3 vol.% of 8 μm (dia.) nickel microfibers have been utilized to entrap ∼30 vol.% of 100-200 μm dia. porous Al₂O₃. ZnO and CaO were then highly dispersed onto the pore surface of the entrapped Al₂O₃ by the incipient wetness impregnation method. Due to the unique combination of surface area, pore size/particle size, thermal conductivity, and void volume, the resulting microfibrous catalyst composites provided significant improvement of catalytic bed reactivity and utilization efficiency when used in methanol steam reforming. Roughly 260 mL/min of reformate, comprising >70% H ₂, <5% CO and trace CH₄, with >97% methanol conversion, could be produced in a 1 cm³ bed volume of our novel microfibrous entrapped ZnO-CaO/Al₂O₃ catalyst composite at 470 °C with a high weight hourly space velocity (WHSV) of 15 h^-1 using steam/methanol (1.3/1) mixture as feedstock. Compared to a packed bed of 100-200 μm ZnO-CaO/Al₂O₃, our composite bed provided a doubling of the reactor throughput with a halving of catalyst usage.