Aqueous interfaces are ubiquitous in technological applications and in the environment and govern numerous important phenomena, including corrosion, photoelectrochemical splitting of water, weathering of rocks, cloud droplet nucleation, the concentration of trace gases in polar regions, and thundercloud electrification. A detailed understanding of these processes requires the investigation of aqueous interfaces with chemical sensitivity and interface specificity under ambient conditions, <i>i.e.</i>, temperatures above 200 K and water vapour pressures in the milliTorr to tens of Torr pressure range. Ambient pressure X-ray photoelectron spectroscopy is an excellent method to probe the heterogeneous chemistry of these interfaces and has been applied to a number of different aqueous interfaces, including ultrathin water films on metals and oxides, bulk liquid/solid interfaces, the surface of aqueous solutions in the presence of the equilibrium vapour pressure as well as trace gases, and the surface of ice, which at temperatures close to the melting point is covered by a thin liquid-like layer. The challenge for XPS experiments on aqueous interfaces under ambient conditions is not only the elevated pressure at which these experiments have to be carried out, but equally so the preparation of clean, well controlled aqueous samples with high cleanliness and reproducibility. In this talk we will review the progress that has been made in the area of APXPS experiments on aqueous systems and provide an outlook on opportunities for future research in this field.

Aqueous interfaces investigated under ambient conditions by XPS

254th National Meeting (2017)

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