Synchrotron and Free electron laser Radiation: generation and application (SFR-2018)

Features of stabilization of Pd and Rh in model low-percentage supported catalysts

Not scheduled

15m

Conference Hall (Budker INP)

Poster X-ray spectroscopy

Speaker

Dr Vladimir Kriventsov (Boreskov Institute of Catalysis)

Description

Increased requirements for environmental safety and the introduction of new standards for the content of harmful impurities in waste gas mixtures led to significant progress in the development of devices to neutralize automobile exhausts and emissions of industrial gases based on catalytic systems containing noble metals, especially palladium and rhodium, allowing the transition to processes of low-temperature oxidation. The present work is devoted to studying the features of the state of palladium and rhodium and its stabilization centers in the active component of model low-percentage (less than 1%) palladium-rhodium catalysts supported on oxide carriers using XANES/EXAFS methods. All XANES/EXAFS spectra (Pd-K, Rh-K) of the studied samples were recorded at Siberian Synchrotron and Terahertz Radiation Center (SSTRC, Novosibirsk). The state and local structure arrangement of supported metal nanoparticles of the studied catalytic nanosystems was characterized in detail. Correlations between their catalytic properties, local structure distortions and state of metal components were demonstrated. The interatomic distances and corresponded coordination numbers were calculated by fitting. All possible structural models were discussed. Additionally, morphology and composition of the samples of catalysts were studied by the HRTEM, EDX and XPS methods. The data obtained by all the methods are in a good agreement. The work has been supported by grant of Russian Science Foundation (project №16-13-10192). Vladimir Kriventsov thanks to the Russian Foundation for Basic Research for support of the analysis of the local structure (projects No. 16-03-01139, 17-33-50198, 18-03-01251).