Optical Spectroscopy Methods in the Estimation of the Thermal Stability of Bimetallic Pd–Rh/Al2O3 Three-Way Catalysts
A series of three-way catalysts containing palladium and rhodium were prepared by an incipient wetness impregnation of support with aqueous solution of [Pd(NH3)4](NO3)2 and Na3[Rh(NO2)6] compounds. Both pure and La-doped aluminum oxides were used as a support. The catalysts showed very close activity under stoichiometric and reductive conditions, but were different in terms of thermal stability being tested in a prompt thermal aging regime. UV–Vis and luminescence spectroscopies were found to be informative for diagnostics of rhodium and palladium concentration and state, thus giving the possibility to follow the changes taking place with active components (migration, agglomeration, bulk diffusion).
KeywordsThree-way catalysts Prompt thermal aging Luminescence spectroscopy UV–Vis spectroscopy Metal migration
Spectroscopic study was performed under support of the Russian Foundation for Basic Research (grant number 16-08-01283a). Financial support from the Ministry of Science and Higher Education (project number AAAA-A17-117041710086-6) is gratefully acknowledged. Theoretical estimations were carried out within the Governmental Program “Science” of Tomsk Polytechnic University (project No. 4.5200.2017).
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