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 H 2 O, 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 H 2 O dissociation with adsorbed CO assists further surface clean off. Enhanced NO reduction activity on the “de-poisoned” interface leads to a pronounced increase in N 2 selectivity. Preferred production of NH 3 at low NO and high CO and H 2 O concentration indicates that water gas shift intermediates are linked to increased surface hydrogen activity and increased NH 3 formation. • Synthesis approach tunes the extent of Pd-perovskite interface. • Effect of the interface dimensions on deNO x reactivity in the presence of H 2 O. • Reaction of H 2 O species with adsorbed CO assists surface de-poisoning. • Effective use of lattice oxygen for CO oxidation at the phase boundary. • Water gas shift intermediates causes enhanced NH 3 formation.