(575g) Paper-Structured Catalyst with Layered Fiber-Network Microstructure for Efficient Autothermal Hydrogen Production

Microstructured catalysts have
recently occupied the attention as promising catalytic materials due to their
efficient diffusion property of heat and reactants during various catalytic
reactions. In
this study, we successfully prepared the novel microstructured catalyst
composed of copper-zinc oxide (Cu/ZnO) catalyst powder and ceramic fiber by
using a high-speed and low-cost papermaking technique. As-prepared materials,
called paper-structured catalyst in this study, were cardboard-like,
lightweight, flexible and easy-to-handle in practical use. The fine Cu/ZnO
catalyst powders were well scattered on the layered ceramic fiber-network
microstructure (average pore size: ca. 20 µm, porosity: ca. 50%) in the
paper composite. Subsequently, paper-structured catalysts were applied to the
autothermal reforming of methanol to produce hydrogen for fuel cell
applications. The
methanol conversion performed with the paper-structured catalyst reached up to
ca. 90% comparable with that of the original catalyst powder, surpassing by far
that of the commercial pellet-type catalyst. In general, the carbon monoxide
by-product acts as a catalytic poison for the Pt anode electrocatalyst of fuel
cells. In the case of the paper-structured catalyst, the carbon monoxide
concentration was drastically reduced to around 3000 ppm, which was less than
half that produced with catalyst powder. Besides, paper-structured catalyst
showed a high catalytic durability; the decrease in the methanol conversion was
only ca. 6% during long-term cycle reforming test, whereas the performance of
original catalyst powder decreased by ca. 20%. The flow rate of the generated
gas and the internal temperature of the reactor with paper-structured catalyst
were relatively stable as compared with powder and pellet; therefore it was suggested
that the paper-specific fiber-network microstructure possibly provided a
uniform flow of heat and reactants inside the catalyst layer, and contributed
to some improvement of catalytic stability as well as reactivity and durability.
The paper-structured catalysts having paper-like flexibility and fabricating
properties are allowed to fit various reactor configurations, and thus are
expected as promising materials for improving the practical utility and
catalytic performance in the catalytic gas-reforming process.