Time-dependent carbide phase formation in palladium nanoparticles. (October 2020)

• Record Type: Journal Article
• Authors: Skorynina, A.A.; Tereshchenko, A.A.; Usoltsev, O.A.; Bugaev, A.L.; Lomachenko, K.A.; Guda, A.A.; Groppo, E.; Pellegrini, R.; Lamberti, C.; Soldatov, A.V.
• Is Part Of: Radiation physics and chemistry. Volume 175(2020:Oct.)
• Publication Date: 2020-10
• Subjects: Palladium carbide -- XANES -- EXAFS -- XRPD; Radiation chemistry -- Periodicals; Radiometry -- Periodicals; Radiation -- Periodicals; Chimie sous rayonnement -- Périodiques; 539.2
• DOI: 10.1016/j.radphyschem.2018.11.033
• Languages: English
• ISSNs: 0969-806X

Abstract

Abstract: Palladium-based catalysts are widely applied for the selective hydrogenation of acetylene in acetylene/ethylene mixtures. Under reaction conditions, palladium hydride or carbide phases can be formed, which change the catalytic properties of material. In the current work, we focus on the process of carbide phase formation in supported palladium nanoparticles (NPs) exposed to acetylene and ethylene at 100 °С. The evolution of carbide phase was monitored in situ by X-ray absorption near edge structure (XANES) spectroscopy, extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray powder diffraction (XRPD). The degree of the lattice expansion determined by XRPD and EXAFS was extrapolated to obtain the saturated values, which were found to be similar for ethylene- and acetylene-exposed samples, while the rate of carbide formation was higher in the case of acetylene. Highlights: The palladium carbide phase was investigated by XANES, EXAFS and XRPD. Similar carbide phase is formed after long exposure to ethylene and acetylene. The observed carbide formation rate is faster in acetylene than in ethylene. Carbide formation in Pd nanoparticles has fast and slow stages.