Abstract
Combining X-ray photoelectron spectroscopy with the standing wave technique, we investigated adsorption of a monolayer of water on Ti-oxide-terminated SrTiO3(001) in ultra-high vacuum (UHV). At room temperature, the surface is water-free but hydroxylated. A quarter monolayer of hydroxyl is tightly bound 1.85 ± 0.06 A above the TiO2 surface. Deposited at a low temperature, a monolayer of water adsorbs with the oxygen located 2.55 ± 0.2 A above the surface, apparently close to atop Ti, but H2O is unstable at 200 K. A fraction desorbs, in part under the X-ray beam, but a major fraction of H2O dissociates immediately, with the liberated hydrogen most likely attaching to a surface oxygen. The produced hydroxyls bind only loosely to the surface, are unstable at 200 K, and rapidly desorb once the surface is water-free. Although our study was conducted in UHV, the presented results suggest that Ti-oxide-terminated SrTiO3(001) may possess a high catalytic activity toward hydrolysis under realistic conditions.
Highlights
The goal of identifying materials, routes, and strategies for carbon-neutral renewable energy production such as directly producing hydrogen fuel, eventually on an industrial scale, motivates intensive research
Our study was conducted under ultrahigh vacuum (UHV) conditions and we could not analyze the reaction products, the study suggests that STO(001) possesses a high catalytic activity in the water splitting reaction
We studied the adsorption and decomposition of water on a Ti-oxide-terminated STO(001) surface using photoelectron spectroscopy combined with the X-ray standing wave (XSW) technique
Summary
The goal of identifying materials, routes, and strategies for carbon-neutral renewable energy production such as directly producing hydrogen fuel, eventually on an industrial scale, motivates intensive research. A promising path toward fuel production from water and sunlight involves photo-electrochemistry, suggested by the early finding of Fujishima and Honda[1] of electrochemical photolysis of water at a TiO2 electrode. We find that the majority of the water layer in contact with the Tioxide-terminated surface deprotonates rapidly. This demonstrates that the (001) surface of STO exhibits a very low activation barrier toward decomposition of water. Our study was conducted under UHV conditions and we could not analyze the reaction products, the study suggests that STO(001) possesses a high catalytic activity in the water splitting reaction
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
