For this work, we have investigated the structure and dynamics of water (D2O) adsorbed on TiO2(110) for coverages between 0 and 1 monolayer with infrared reflection absorption spectroscopy (IRAS) and ab initio molecular dynamics (AIMD) simulations. For D2O coverages as low as 0.4 monolayers (ML) on a hydroxylated surface, IR spectra typical of hydrogen-bonded chains of water molecules are observed. However, for D2O coverages ≥ 0.3 ML, a sharp, high frequency peak is also observed in the p-polarized spectra that is red-shifted relative to the bridging hydroxyl peak. This new peak is not observed for water adsorbed on an oxidized surface. Based on the AIMD simulations and comparisons with previous IR spectra for TiO2 nanoparticles, the new peak is assigned to terminal hydroxyl groups produced by dissociative adsorption of some of the water on TiO2(110). The simulations indicate that water dissociation is related to the presence of defect electrons in the system, but not due to direct interactions between adsorbed water and bridging hydroxyls.
Petrik, Nikolay G., et al. "Mixed Molecular and Dissociative Water Adsorption on Hydroxylated TiO<sub>2</sub>(110): An Infrared Spectroscopy and Ab Initio Molecular Dynamics Study." Journal of Physical Chemistry. C, vol. 126, no. 51, Dec. 2022. https://doi.org/10.1021/acs.jpcc.2c07063
Petrik, Nikolay G., Baer, Marcel D., Mundy, Christopher J., & Kimmel, Gregory A. (2022). Mixed Molecular and Dissociative Water Adsorption on Hydroxylated TiO<sub>2</sub>(110): An Infrared Spectroscopy and Ab Initio Molecular Dynamics Study. Journal of Physical Chemistry. C, 126(51). https://doi.org/10.1021/acs.jpcc.2c07063
Petrik, Nikolay G., Baer, Marcel D., Mundy, Christopher J., et al., "Mixed Molecular and Dissociative Water Adsorption on Hydroxylated TiO<sub>2</sub>(110): An Infrared Spectroscopy and Ab Initio Molecular Dynamics Study," Journal of Physical Chemistry. C 126, no. 51 (2022), https://doi.org/10.1021/acs.jpcc.2c07063
@article{osti_1986454,
author = {Petrik, Nikolay G. and Baer, Marcel D. and Mundy, Christopher J. and Kimmel, Gregory A.},
title = {Mixed Molecular and Dissociative Water Adsorption on Hydroxylated TiO<sub>2</sub>(110): An Infrared Spectroscopy and Ab Initio Molecular Dynamics Study},
annote = {For this work, we have investigated the structure and dynamics of water (D2O) adsorbed on TiO2(110) for coverages between 0 and 1 monolayer with infrared reflection absorption spectroscopy (IRAS) and ab initio molecular dynamics (AIMD) simulations. For D2O coverages as low as 0.4 monolayers (ML) on a hydroxylated surface, IR spectra typical of hydrogen-bonded chains of water molecules are observed. However, for D2O coverages ≥ 0.3 ML, a sharp, high frequency peak is also observed in the p-polarized spectra that is red-shifted relative to the bridging hydroxyl peak. This new peak is not observed for water adsorbed on an oxidized surface. Based on the AIMD simulations and comparisons with previous IR spectra for TiO2 nanoparticles, the new peak is assigned to terminal hydroxyl groups produced by dissociative adsorption of some of the water on TiO2(110). The simulations indicate that water dissociation is related to the presence of defect electrons in the system, but not due to direct interactions between adsorbed water and bridging hydroxyls.},
doi = {10.1021/acs.jpcc.2c07063},
url = {https://www.osti.gov/biblio/1986454},
journal = {Journal of Physical Chemistry. C},
issn = {ISSN 1932-7447},
number = {51},
volume = {126},
place = {United States},
publisher = {American Chemical Society},
year = {2022},
month = {12}}