Investigation of NO Reduction by H2 on Pd Monolith with Transient and Isotopic Exchange Techniques: II. H2/D2 Exchange in the Reduction of NO

The kinetics and mechanism of catalytic reduction of nitrogen oxide (NO) by hydrogen on an alumina-based palladium monolith were studied under atmospheric pressure at 155°C. Transient kinetic experiments, as well as isotopic exchange techniques, were applied in order to improve understanding of the reactions occurring on the surface of the noble metal catalyst. Nitrogen, nitrous oxide, ammonia, and water were detected as reaction products in the reduction of nitrogen oxide by hydrogen. The dissociation of NO on the catalyst surface is the crucial step affecting the overall reaction. Ammonia was formed by stepwise hydrogenation of adsorbed nitrogen atoms, which was confirmed by isotope transient techniques. Reaction pathways explaining the reduction of NO with hydrogen and deuterium were proposed.