August 25, 2023
Journal Article

Origin of Hydroxyl Pair Formation on Reduced Anatase TiO2(101)


The interaction of water with metal oxide surfaces is of key importance to several research fields and applications. Because of its ability to photo-catalyze water splitting, reducible anatase TiO2 (a-TiO2) is of particular interest. Here, we combine experiments and theory to study the dissociation of water on reduced a-TiO2(101). Following large water exposures at room temperature, point-like protrusions appear on the a-TiO2(101) surface, as shown by scanning tunneling microscopy (STM). These protrusions originate from hydroxyl pairs, consisting of terminal and bridging OH groups, OHt / OHb, as revealed by infrared reflection absorption spectroscopy (IRRAS) and ultraviolet photoelectron spectroscopy (UPS) experiments. Utilizing density functional theory (DFT) calculations, 2 we offer a comprehensive model of the water / a-TiO2(101) interaction that reconciles previously published data. Our model also explains why the hydroxyl pairs are stable surface species up to ~480 K, as found experimentally.

Published: August 25, 2023


Adamsen K.C., N.G. Petrik, W. Dononelli, G.A. Kimmel, T. Xu, Z. Li, and L. Lammich, et al. 2023. Origin of Hydroxyl Pair Formation on Reduced Anatase TiO2(101). Physical Chemistry Chemical Physics 25, no. 19:13645-13653. PNNL-SA-178908. doi:10.1039/D3CP01051A

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