Kinetic study of higher alcohol synthesis directly from syngas over CoCu/SiO2 catalysts

Abstract

Higher alcohol synthesis (HAS) directly from syngas is one of the most promising approaches for utilizing nonoil resources cleanly and efficiently. A series of bimetallic CoCu catalysts with different Co/Cu ratios were prepared using a SiO2 support. The structure of Cu modified Co catalysts was characterized using HRTEM, in/ex situ X‐ray diffraction, and temperature‐programmed reduction. It was evidenced that nanoscale metal particles were formed and the reduction of Co oxide at above 673 K. Meanwhile, the interaction between Co and Cu on the surface was assumed to be responsible for the enhanced selectivity to HAS. The intrinsic kinetics for this reaction was performed over a CoCu/SiO2 catalyst under realistic conditions. The kinetic parameters, including apparent activation energies and reaction orders, were calculated through power‐law models. With the combination of chain growth probability and kinetics, the effect of temperatures on the reaction mechanism and the Cu promotional effects on Co catalysts were elaborated. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1797–1809, 2014