In2O3-based catalysts have shown high activity and selectivity for CO2 hydrogenation to methanol, however the origin of the high performance of In2O3 is still unclear. To elucidate the initial steps of CO2 hydrogenation over In2O3, we have combined X-ray Photoelectron Spectroscopy (XPS) and Density Functional Theory (DFT) calculations to study the adsorption of CO2 on the In2O3(111) crystalline surface with different terminations, namely the stoichiometric, the reduced, and the hydroxylated surface, respectively. The combined approach confirms that the reduction of the surface results in the formation of In ad-atoms and that water dissociates on the surface at room temperature. A comparison of the experimental spectra and the computed core-level-shifts (using methanol and formic acid as benchmark molecules) suggests that CO2 adsorbs as a carbonate on all surface terminations. We find that CO2 adsorption is hindered by hydroxyl groups on the hydroxylated surface.
@article{arxiv.2308.12657,
title = {The effect of different In$_2$O$_3$(111) surface terminations on CO$_2$ adsorption},
author = {Sabrina M. Gericke and Minttu M. Kauppinen and Margareta Wagner and Michele Riva and Giada Franceschi and Alvaro Posada-Borbón and Lisa Rämisch and Sebastian Pfaff and Erik Rheinfrank and Alexander M. Imre and Alexei B. Preobrajenski and Stephan Appelfeller and Sara Blomberg and Lindsay R. Merte and Johan Zetterberg and Ulrike Diebold and Henrik Grönbeck and Edvin Lundgren},
journal= {arXiv preprint arXiv:2308.12657},
year = {2023}
}