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Description
This work presents the results of a study of the local structure of the active component of mono-, bi-metallic low-percentage (~1%) catalysts (containing Pt, Au, Pd, Ru) stabilized on oxide carriers using XAFS method (XANES/EXAFS). Studying the nature of nano-forms of noble metal stabilization is promising for creating effective catalysts for various applications, including catalytic systems for alternative energy applications. The development of synthesis methods can lead to a significant economic gain, due to the reduction of the metal content and optimization of the catalytic properties of the system. Model catalysts were prepared from mono-and bimetallic complexes, with varying synthesis methods: sol-gel, ion exchange, impregnation, reducing modes, and the nature of carriers. XAFS (XANES/EXAFS) spectra (Pt-L3, Au-L3, Pd-K, Ru-K) of studied samples were recorded at SSTRC, Novosibirsk. Genesis of the local structure of the active component was studied, including the study of oxidized precursors and catalysts after reducing and activation. It is established that depending on the background, it is possible to form various nanoscale forms of noble metals localized on the surface of the oxide carrier. Additionally, the samples were studied by XRD, XPS, XRFA, HRTEM. Variants of possible structural models are considered in detail.
The work was carried out in the framework of the RFBR projects no. 19-05-50046, 18-03-01251. The work was done at the shared research center SSTRC on the basis of the Novosibirsk FEL/VEPP-4-VEPP-2000 complex at BINP SB RAS, using equipment supported by project RFMEFI62119X0022.
