Preparation and characterization of Pt-Ba-Al2O3 coatings obtained by spray pyrolysis

Pt-Ba-Al2O3 coatings were obtained by spray pyrolysis deposition on stainless steel foil. The XRD results showed that the coatings consisted from Ba carbonate and Pt (fcc) phases. SEM micrographs demonstrated that the coatings are smooth and compact. The XPS data confirmed that Ba and Pt are in close contact. Pt crystallite size is only slightly influenced by the order of Pt and Ba deposition and the dispersion of Pt is in the narrow range from 28 to 33% for all samples. Catalyst component deposition order affects NOx storage capacity. Simultaneous deposition of Ba and Pt on already formed Al2O3 substrate produces the most efficient catalyst. Pt deposited on top of the Ba layer results in slightly reduced NOx storage capacity, while deposition of Pt on the separated layer with Ba layer on top significantly reduces the ability for NOx storage.