CO2 activation for methanol synthesis on copper and indium oxide surfaces
Licentiate thesis, 2019
In this thesis, we investigate the surface active phase and its effect on CO2 adsorption on Cu(100) and In2O3(110) with the use of density functional theory (DFT) calculations and ab-initio thermodynamics. Our results are compared to ambient pressure X-ray photoelectron emission spectroscopy (XPS) experiments. CO2 adsorption is the initial step in the reduction process. Hence, understanding of the active catalyst phase, and its effect on the adsorption process, is the first step for the rationalization of the catalytic processes on these systems. Simultaneously, understanding the electronic structure that allows for the high activity, might aid the rational design of better catalysts for CO2 activation.
Our results show that Cu(100) oxidizes from the pristine surface to a p(2×2) overlayer at 0.25 ML followed by a reconstruction to a (2√2×√2)R45 (MR) structure at 0.50 ML. Moreover, dissociative adsorption of CO2 on Cu(100) occurs predominantly at surface steps. In2O3(110) is found to heavily hydroxylate in presence of H2 and/or H2O. Hydroxylation with H2 causes the undercoordinated In-sites to change oxidation state (from In 3+ to In 2+), while H2O does not. We suggest that the redox capacity of the undercoordinated In-site are responsible for the adsorption of CO2 on indium oxide, whereas oxygen vacancies act as spectators. Our results are in qualitative agreement with the experimental observation of heavy hydroxylation and the suppression of the reverse water gas shift on indium oxide
Density functional theory
Alvaro Posada Borbon
Chalmers, Physics, Chemical Physics
Initial oxidation of Cu(100) studied by X-ray photo-electron spectroscopy and density functional theory calculations
Surface Science,; Vol. 675(2018)p. 64-69
Steps Control the Dissociation of CO2 on Cu(100)
Journal of the American Chemical Society,; Vol. 140(2018)p. 12974-12979
A. Posada-Borbón and H. Grönbeck, CO2 adsorption on hydroxylated In2O3(110)
Atomistic Design of Catalysts
Knut and Alice Wallenberg Foundation, 2016-01-07 -- 2021-06-30.
C3SE (Chalmers Centre for Computational Science and Engineering)
Other Chemical Engineering
Other Physics Topics
Other Chemistry Topics
Chalmers University of Technology
PJ lecture hall, Fysikgården 2B
Opponent: Prof. Jonas Weissenrieder, KTH Royal Institute of Technology (Kungliga Tekniska högskolan), Stockholm, Sweden.