Platinum dispersion measurements for Pt/BaO/Al2O3, NOx storage catalysts

• Published in: Applied catalysis. A, General Vol. 296; no. 2; pp. 157 - 168
• Main Authors: DAWODY, Jazaer, EURENIUS, Lisa, ABDULHAMID, Hussam, SKOGLUNDH, Magnus, OLSSON, Eva, FRIDELL, Erik
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 12.12.2005
• Subjects: Barium; Catalysis; Characterization; Chemistry; CO chemisorption; CO TPD; EDS; Exact sciences and technology; General and physical chemistry; H2 chemisorption; N2O dissociation; Platinum dispersion; SEM; TEM; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Nitrogen oxide; Chemisorption; Scanning electron microscopy; Barium; Platinum dispersion; CO TPD; Transition metal; N2O dissociation; Supported catalyst; Dispersion; Characterization; Heterogeneous catalysis; CO chemisorption; H2 chemisorption; Transmission electron microscopy; Storage; Platinum; EDS; SEM; Dissociation; Nitrogen protoxide; Alumina; TEM
• ISSN: 0926-860X; 1873-3875; 1873-3875
• DOI: 10.1016/j.apcata.2005.07.060

In this investigation different experimental methods to determine the platinum dispersion of Pt/BaO/Al2O3 NOx storage catalysts are compared. The dispersion of platinum is determined independently using temperature programmed desorption of CO, dissociation of N2O, static volumetric CO and H2 chemisorption, dynamic CO chemisorption and transmission electron microscopy. For Pt/BaO/Al2O3, reproducible results are obtained when the platinum dispersion is determined from N2O dissociation, CO and H2 chemisorption. However, repeated CO-TPD experiments result in decreased amount of desorbed CO, which limits this method to determine platinum dispersion for Pt/BaO/Al2O3 samples. For Pt/Al2O3, similar values for platinum dispersion are obtained for all methods used in the study.In addition to the platinum dispersion investigations, the surface morphology of Pt/BaO/Al2O3 samples and the distribution of different elements are studied using SEM-EDS. The SEM-EDS analyses show that the platinum is evenly distributed over the entire sample surface, while the distribution of barium is more uneven.