In Situ X-ray Absorption Spectroscopy Study of the Deactivation Mechanism of a Ni-SrTiO Photocatalyst Slurry Active in Water Splitting.

We used in situ X-ray absorption spectroscopy (XAS) to investigate the composition-performance correlation of Ni-SrTiO photocatalysts active for water splitting. After preparation and exposure to ambient conditions, the Ni particles on SrTiO consist of Ni(0) and Ni(II) phases, with a 4:1 at % ratio, in a metal/oxide core/shell configuration, as confirmed by XPS and TEM-EDX. In situ XAS experiments using an aqueous slurry of the Ni-SrTiO photocatalyst and simultaneous continuous exposure to 365 nm light with a power density of 100 mW cm and the X-rays do not reveal significant changes in oxidation state of the Ni particles.