Orientation of acetic acid hydrogen bonded to acetate terminated TiO2(110)

Abstract

Acetic acid is a common pollutant for which photocatalytic degradation over titania provides a mitigating strategy. Knowledge of the bonding of acetate/acetic acid to this substrate is needed to aid interpretation of the photocatalytic data. In this work we use ambient pressure near edge X-ray absorption fine structure to measure the coverage and geometry of acetate in the TiO2( 110) contact layer as well as acetic acid in an additional layer. A saturation coverage of 0.5 monolayers in both layers is found up to an acetic acid pressure of 10 -1 Torr at 266 K.The geometry of acetate appears to be unchanged by adsorption of an additional layer of acetic acid, which involves a majority species bidentate bonded to neighboring Ti5c sites and a minority species bonded in a perpendicular geometry. Acetic acid has a similar geometry dictated by hydrogen bonding to the contact layer as well as the substrate.

Polaron-Adsorbate Coupling at the TiO2(110)-Carboxylate Interface

“…This is accompanied by the protonation of bridging O (OH b ) and the formation of a (2 × 1) majority phase adsorption structure (see Figure (a)). A minority carboxylate component is also present, which is a monodentate species oriented perpendicular to [001] and accounts for up to 1/3 of the interface. ,− Formic and acetic acid adsorption saturates at ∼0.5 ML in UHV at 298 K, where a monolayer corresponds to the number of surface unit cells. The two terminations are denoted FA- and AA-R110, respectively.…”

VerSoX B07-B: a high-throughput XPS and ambient pressure NEXAFS beamline at Diamond Light Source

“…Although its roots lie in ultra-high vacuum (UHV) studies of solids and their interactions with the gas phase (Chen, 1997;Tamenori, 2013), NEXAFS with soft X-rays has emerged as a versatile analytical tool for a broad range of applications, with near-ambient pressure operation facilitating even operando or in situ analysis of materials. Contemporary applications span both fundamental and applied research, including fields such as catalysis (Eren et al, 2020;Liu et al, 2023;Tolosana-Moranchel et al, 2023), studies of liquids (Smith & Saykally, 2017), corrosion (Dwivedi et al, 2017), biological materials (Akabayov et al, 2005), batteries and electrolytes (Yang & Devereaux, 2018;Ye et al, 2017;Swallow et al, 2023a), ionic liquids (Fogarty et al, 2017;Seymour et al, 2022), molecular orientation at surfaces (Dover et al, 2020;Stoodley et al, 2023), art conservation (Willneff et al, 2014), local bonding of organic molecules in crystals (Edwards et al, 2022), speciation in solution (Stevens et al, 2015) and geochemistry (Koike et al, 2020).…”