XAFS study of catalytic nanosystems promising for environmental catalysis
Recently, low-content supported mono- and bimetallic catalytic nanosystems containing transient and noble metals inspire great interest in researchers, because of their practical application for a wide range of processes of environmental catalysis owing to the possibility of varying catalytic properties, relatively low cost of the final products, and ease of recovery of expensive components of the exhausted catalysts. The samples of modeljed catalysts ~1% (Pt, PtCo, Pd, PdCo, PdMn and others) were obtained by varying preparation methods of active component (deposition-precipitation, zol-gel, ion exchange, MOCVD ) from mono- and heterometallic precursors of different nature. Nanoparticles of active component were located on various supports (C, SiO2, Al2O3, TiO2, ZrO2) and different activation and reduction conditions were used. All XAFS spectra of the studied samples were recorded at the Siberian Synchrotron and Terahertz Radiation Center (SSTRC, Novosibirsk). Genesis of the state and local structure arrangement of supported metal nanoparticles of the studied catalytic nanosystems were 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 TEM, EDX and XPS methods . The data obtained by all the methods are in a good agreement.
The work was done using the infrastructure of the Shared-Use Center “Siberian Synchrotron and Terahertz Radiation Center (SSTRC)” based on VEPP-3 of BINP SB RAS. This work was supported by RFBR (140301066, 163350248, 163350249, 163350250, 160301139), SB RAS comprehensive program II.2P (Project 0305-2015-0018).