Paola Sabrina Barbato

Structuring CuO/CeO2 Catalyst as Option to Improve Performance Towards CO-PROX

In this work we review our results on the preparation, characterization and testing of copper/ceria structured catalysts for CO abatement in H2-rich streams by preferential oxidation. Copper/ceria wash-coated monoliths were prepared by a modified dip coating procedure. The effect of the substrate properties (cell density and wall thermal conductivity) on the catalytic performances and the effect of the slurry preparation on the wash-coat adhesion were investigated. The role of the temperature profile on the performances was also studied and the dependence of thermal profile on the cell density and the wall thermal conductivity was shown. Monoliths with both high cell density and high thermal conductivity of the substrate represent the best option, providing a very good thermal management of the process due to the reduction of hot spots over the catalyst surface. On the other hand, wash-coat adhesion is significantly improved by the presence of nanometric ceria in the slurry used to dip-coat the monoliths, due to the partial penetration of the wash-coat into the substrate macropores. Moreover, due to the modifications of the specific surface area and the pore size distribution upon addition of nanometric ceria to the slurry, copper dispersion and, then, CO selectivity were enhanced as well.

CFD Simulations of Copper-Ceria Based Microreactor for COPROX

Abstract A CFD model of a copper-ceria based micro-reactor for the CO preferential oxidation reaction is developed. Simulations are performed by changing the thermal conductivity of the support and the oxygen inlet concentration. It is found that the value of the wall thermal conductivity has a significant role on the temperature profiles, hot-spot and selectivity. On increasing the O2 content, the CO selectivity decreases. An increase of the oxygen content anticipates the activation of the H2 oxidation, thus competing with CO oxidation. Conversely, at low values of the O2 content, the H2 oxidation is activated only after an almost complete CO oxidation is obtained. From the results it appears that the temperature control and management in the reactor is a key for increasing the CO selectivity at high CO conversion.