Tailoring the metal-perovskite interface for promotional steering of the catalytic NO reduction by CO in the presence of H2O on Pd-lanthanum iron manganite composites

We steer the catalytic performance and morphology of Pd – lanthanum iron manganite (LFM) perovskite interfaces towards optimum NO+CO reactivity in presence of water by following different preparation approaches. Strong CO adsorption for samples without Pd-perovskite interface acts as an inhibitor for adsorption/dissociation of NO, while samples with an extended interface, additionally aided by H2O, show reduced CO poisoning. The optimized use of lattice oxygen for CO oxidation at the phase boundary and its replenishment from NO dissociation allows for the formation of more poisoning-resistant active sites for NO activation. Reaction of species from H2O dissociation with adsorbed CO assists further surface clean off. Enhanced NO reduction activity on the “de-poisoned” interface leads to a pronounced increase in N2 selectivity. Preferred production of NH3 at low NO and high CO and H2O concentration indicates that water gas shift intermediates are linked to increased surface hydrogen activity and increased NH3 formation.