Chemical Engineering Science, Vol.135, 312-322, 2015
Kinetics study of C2+ oxygenates synthesis from syngas over Rh-MnOx/SiO2 catalysts
C2+ oxygenates synthesis directly from syngas is one of the most promising processes for utilizing non-oil fossil fuels cleanly and efficiently. Bimetallic Rh-MnOx/SiO2 catalysts with different Rh/Mn ratios were prepared and characterized with HRTEM. TPD and TPR. It was evidenced that Rh nanoparticles were stabilized in a range 0.5-2.0 nm via the promotional effects of MnOx. Meanwhile the interface between Rh and MnOx was assumed to be favorable for the insertion of CO into Rh-CHx to form C2+ oxygenates; the intrinsic kinetics was performed over Rh (1.5 wt%)-Mn (0.4 wt) catalysts at different temperatures. The kinetic parameters, including apparent activation energies and reaction orders, were calculated. With the combination of structural modification and kinetics, the reaction mechanism and the Mn promotional effects on Rh catalysts were elaborated. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords:C2+ oxygenates;Intrinsic kinetics;Syngas;Bimetallic Rh-Mn catalysts;MnOx promotional effect;Mechanism