Thermochemistry and micro-kinetic analysis of methanol synthesis on ZnO (0001)

Andrew James Medford, Jens Sehested, Jan Rossmeisl, Ib Chorkendorff, Felix Studt, Jens K. Nørskov, Poul Georg Moses

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In this work, we examine the thermochemistry of methanol synthesis intermediates using density functional theory (DFT) and analyze the methanol synthesis reaction network using a steady-state micro-kinetic model. The energetics for methanol synthesis over Zn-terminated ZnO (0001) are obtained from DFT calculations using the RPBE and BEEF-vdW functionals. The energies obtained from the two functionals are compared and it is determined that the BEEF-vdW functional is more appropriate for the reaction. The BEEF-vdW energetics are used to construct surface phase diagrams as a function of CO, H2O, and H2 chemical potentials. The computed binding energies along with activation barriers from literature are used as inputs for a mean-field micro-kinetic model for methanol synthesis including the CO and CO2 hydrogenation routes and the water–gas shift reaction. The kinetic model is used to investigate the methanol synthesis rate as a function of temperature and pressure. The results show qualitative agreement with experiment and yield information on the optimal working conditions of ZnO catalysts.
Original languageEnglish
JournalJournal of Catalysis
Volume309
Pages (from-to)397-407
ISSN0021-9517
DOIs
Publication statusPublished - 2014

Keywords

  • Zinc oxide
  • Catalysis
  • Kinetics
  • DFT
  • MeOH
  • Phase diagram

Cite this