The surface reactivity of TiO2 is governed in many applications by the hydroxyl groups on its surface. FTIR spectroscopy is the most common method used to study surface hydroxyls. However, interpretation of the observed bands of powder samples is not straightforward. In this work, we propose a facet-specific assignment of the surface hydroxyls of pyrogenic TiO2 (commonly known as P25 and P90) by comparison between experimentally observed FTIR bands under dry conditions with DFT-calculated vibrational frequencies. The vibrational frequency of surface hydroxyls on different TiO2 surfaces are sufficiently distinct to allow them to be used for facet identification. This approach could be used for characterizing the morphologies of catalyst particles under working conditions and for in situ or operando studies of facet-specific catalytic activities.

Use of surface hydroxyl frequencies to identify the exposed facets of pyrogenic TiO2 nanoparticles

2019 Spring National Meeting

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