Cu-Ru/MgO systems -- spectroscopic evidence of the formation of bimetallic particles: CO adsorption and CO-O[sub 2] interaction

Journal Article · Sun Aug 01 04:00:00 EDT 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1221· OSTI ID:5602351

Ghiotti, G; Boccuzzi, F; Chiorino, A ^[1]; Galvagno, S ^[2]; Crisafulli, C ^[3]

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1. Universita di Torino, Turin (Italy)
2. Universita di Messina, Sant' Agata di Messina (Italy)
3. Universita di Catania (Italy)

Ru/MgO, Cu/MgO, and Ru-Cu/MgO systems were characterized by FT-IR spectroscopy of adsorbed CO. The systems studied contained a total amount of metal of about 2 wt %: RCM100, RCM083, RCM070, RCM046, RCM034, and RCM000, with Ru/(Cu + Ru) atomic ratios 1, 0.83, 0.70, 0.46, 0.34, and 0.00, respectively. A comparison was made between the spectroscopic results and the catalytic properties in propane hydrogenolysis. On the Ru/MgO (RCM100) system CO originated an asymmetric band centered at 2038 cm[sup [minus]1], shifting to lower frequency upon evacuation, in the spectral range of CO linearly adsorbed on (0001) faces. On Cu/MgO (RCM000) CO revealed the presence of two sites on which CO is adsorbed linearly giving bands at 2078 and 2060 cm[sup [minus]1]. On RCM083 catalyst large islands of uncovered Ru coexisted with areas of Ru heavily decorated by Cu, as revealed by the presence, upon CO adsorption, of a band at [approx]2040 cm[sup [minus]1] and of a very broad band at [bar v] < 2000 cm[sup [minus]1]. On RCM070 catalyst only areas of Ru heavily decorated by Cu were present, while on RCM046 and RCM034 samples large islands of uncovered Ru coexisted with areas of Ru heavily decorated by Cu, despite the increase in the Cu content. On the four bimetallic catalysts a variety of Cu(0) sites were revealed, bonding CO linearly (sharp CO stretching bands in the 2140-2098 cm[sup [minus]1] region), belonging to different Cu aggregates adsorbed on Ru microcrystals. These results are consistent with those obtained by catalytic measurements: the minimum catalytic activity and the maximum selectivity in ethane formation are found for the RCM070 sample, which shows only surface Ru(0) heavily decorated by Cu, as expected. 40 refs., 8 figs.

• OSTI ID: 5602351
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 142:2; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ABSORPTION SPECTROSCOPY
ADSORPTION
ALKALINE EARTH METAL COMPOUNDS
ALKANES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
COPPER
ELEMENTS
FOURIER TRANSFORM SPECTROMETERS
HYDROCARBONS
HYDROGENATION
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MEASURING INSTRUMENTS
METALS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTICLES
PLATINUM METALS
PROPANE
RUTHENIUM
SORPTION
SORPTIVE PROPERTIES
SPECTROMETERS
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENTS