Abstract
In-situ analysis of the TiO2/water interface via near ambient pressure–x-ray photoelectron spectroscopy (NAP–XPS) is demonstrated in both a lab based system (NAP-cell configuration) and synchrotron endstation (backfill configuration). Ultra-thin wetting layers of liquid water (∼10 nm) are formed on a rutile TiO2 surface with minimal contamination present in addition to unique insight during the growth of the liquid films as indicated via NAP–XPS, in-situ sample temperature and background vapour pressure monitoring. Chemical changes at the solid/liquid interface are also demonstrated via healing of Ti3+ surface defect states. Photon depth profiling of the as grown liquid layers indicate that the formed films are ultra-thin (∼10 nm) and likely to be continuous in nature. This work demonstrates a novel and flexible approach for studying the solid/liquid interface via NAP–XPS which is readily integrated with any form of NAP–XPS system, thereby making a critical interface of study available to a wide audience of researchers for use in operando electrochemical and photocatalytic research.
Highlights
Introduction pte KeywordsNear ambient pressure (NAP)-XPS, AP-XPS, Ultra-thin wetting layers (UTWL), TiO2, Rutile, solid/liquid interface, Offset Droplet, VerSoX occurs at the solid/liquid interface making the connection of experimental results obtained within ultra-high vacuum (UHV) conditions to the real-world catalysis challenging[6,7].X-ray photoelectron spectroscopy (XPS) has been routinely used in the study of TiO2 surfaces, owing to the inherent elemental and rich chemical information obtainable from the surface region of the sample[8,9]
We present a method of probing the solid / liquid interface between a rutile TiO2 (110) surface and varying thicknesses of liquid water with surface and chemically sensitive NAP-XPS
Results & Discussion ce University of Manchester SPECS DeviSim System: The TiO2 rutile (110) single crystal sample was loaded into the UHV portion of the University of Manchester lab based NAP-XPS system and sputter annealed using standard
Summary
Conor Byrne[1,2], Khadisha M. Zahra[1,2], Simran Dhaliwal[3,4], David C.
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