Mechanistic features for propane reforming by carbon dioxide over a Ni/Mg(Al)O hydrotalcite-derived catalyst
Résumé
A 1.9 wt% Ni/Mg(Al)O hydrotalcite-derived catalyst is studied for the dry reforming of propane to synthesis gas at 600 ↓C and 1 atm. The catalyst showed limited initial deactivation and then was exceptionally stable throughout a 34-day test. Catalyst characterization indicates that the carrier material consists of a mixed Mg(Al)O phase before and after testing, and that carbonate forms on the support surface under dry reforming conditions. The Ni particles are in close contact with, and partially decorated by, the basic support. No carbon whisker formation is obsd. by transmission electron microscopy after catalytic testing. Alternating pulse expts. in a Temporary Anal. of Product-II (TAP-II) reactor system indicate that CO2 is associatively adsorbed on the basic Mg(Al)O carrier and acts as a permanent source of oxygen species for the Ni metal. Propane reacts rapidly with Ni-O species to form CO and H2O. Under TAP conditions, reduced Ni reacts gradually with carbonate from the support to give Ni-O species and CO.