Mechanistic study of the oxidative steam reforming of etoh on rh(111): The importance of the oxygen effect

Cih Ying Syu, Jeng Han Wang

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

This study extensively investigates the catalytic mechanism and oxygen effect in the oxidative steam reforming (OSR) of EtOH on Rh(111) by using plane-wave density functional theory (DFT) and kinetic calculations. The mechanistic results show that both surface acetaldehyde (CH3CHO*) and oxametallacycle (CH2CH2O*) species from Cα-H and Cβ-H bond scissions of surface ethoxy (CH3CH2O*) groups, respectively, are key intermediates. Both of these species can quickly decomposed into surface carbon (C*), methylidyne (CH*), and carbon monoxide (CO*) species, owing to energetic preferences. However, the removal of the adspecies in the formation of major products CO(g) and CO2(g) through high-barrier oxidation steps are considered the rate-determining steps in the overall catalytic process. In the study of the oxygen effect, surface oxygen (O*) species might slightly elevate the barriers for EtOH decomposition, but can lower the barriers for the rate-limiting oxidation steps. The kinetic calculations, which well-predict the experimental observations, indicate that the rates of those oxidation steps can be further increased at high oxygen pressures. These results conclude that the oxygen effect plays a crucial role in the OSR of EtOH on Rh-based catalysts and further implies that the catalytic performance can be improved by using promoters, which have better oxidative capability, and by increasing the oxygen content, which can assist the oxidation process.

Original languageEnglish
Pages (from-to)3164-3174
Number of pages11
JournalChemCatChem
Volume5
Issue number10
DOIs
Publication statusPublished - 2013 Oct 1

Fingerprint

Steam reforming
steam
Oxygen
oxygen
Carbon Monoxide
oxidation
Oxidation
high pressure oxygen
acetaldehyde
kinetics
Kinetics
Acetaldehyde
carbon monoxide
cleavage
plane waves
Carbon monoxide
Density functional theory
methylidyne
density functional theory
Carbon

Keywords

  • Density functional calculations
  • Heterogeneous catalysis
  • Kinetics
  • Reaction mechanisms
  • Rhodium

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

Cite this

Mechanistic study of the oxidative steam reforming of etoh on rh(111) : The importance of the oxygen effect. / Syu, Cih Ying; Wang, Jeng Han.

In: ChemCatChem, Vol. 5, No. 10, 01.10.2013, p. 3164-3174.

Research output: Contribution to journalArticle

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