CO hydrogenation over Co/SiO2: catalytic tests and surface analysis of adsorbed hydrocarbons

Autor: Sellmer, C., Decker, S., Kruse, N.
Zdroj: Catalysis Letters; July 1998, Vol. 52 Issue: 3-4 p131-137, 7p
Abstrakt: We have studied the CO hydrogenation over a Co/SiO2catalyst under mild reaction conditions (up to 4.4 bar total pressure, H2/CO = 2,T= 483K) and performed a post-reaction analysis of the chemical surface composition by means of secondary ion mass spectrometry (SIMS) and temperature-programmed reaction (TPR) in hydrogen gas. A hydrocarbon chain growth probability α = 0.78 was found in the catalytic studies. The SIMS analysis revealed the existence of individually adsorbed CxHyspecies up to C8Hy, in accordance with end-on bonding to the catalyst surface. These species were removed from the catalyst surface in the subsequent H2-TPR experiment. Significant methane desorption occurred at temperatures (⩾500 K) well above those of the longer-chain hydrocarbons indicating either an increasing hydrogenolysis activity of Co metal during H2-TPR or the presence of a more tightly bound “carbidic” adsorbate under FT conditions.
Databáze: Supplemental Index