Origin of hydroxyl pair formation on reduced anatase TiO(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 TiO (a-TiO) is of particular interest. Here, we combine experiments and theory to study the dissociation of water on bulk-reduced a-TiO(101).

Integrated atomic force microscopy and x-ray irradiation for in situ characterization of radiation-induced processes.

Understanding radiation-induced chemical and physical transformations at material interfaces is important across diverse fields, but experimental approaches are often limited to either ex situ observations or in situ electron microscopy or synchrotron-based methods, in which cases the radiation type and dose are inextricably tied to the imaging basis itself. In this work, we overcome this limitation by demonstrating integration of an x-ray source with an atomic force microscope to directly monitor radiolytically driven interfacial chemistry at the nanoscale. We illustrate the value of in situ observations by examining effects of radiolysis on material adhesion forces in aqueous solution as well as examining the production of alkali nitrates at the interface between an alkali halide crystal surface and air.

Direct visualization of radiation-induced transformations at alkali halide-air interfaces.

Radiation driven reactions at mineral/air interfaces are important to the chemistry of the atmosphere, but experimental constraints (e.g. simultaneous irradiation, in situ observation, and environmental control) leave process understanding incomplete.

Observation of Molecular Hydrogen Produced from Bridging Hydroxyls on Anatase TiO(101).

Anatase TiO is used extensively in a wide range of catalytic and photocatalytic processes and is a promising catalyst for hydrogen production. Here, we show that molecular hydrogen was produced from bridging hydroxyls (HO) on the (101) surface of single-crystal anatase (TiO(101)). This stands in contrast to rutile TiO(110), where HO pairs react to form HO.

Crystallization growth rates and front propagation in amorphous solid water films.

The growth rate of crystalline ice (CI) in amorphous solid water (ASW) films was investigated using reflection absorption infrared spectroscopy. Two different experiments were set up to measure rates of the crystallization front propagation from the underlying crystalline template upward and from the vacuum interface downward. In one set of experiments, layers of ASW (5% DO in HO) were grown on a CI template and capped with a decane layer.