Efficient Visible-Light Photocatalytic Water Splitting by Minute Amounts of Gold Supported on Nanoparticulate CeO₂ Obtained by a Biopolymer Templating Method

When irradiated with visible light (λ > 400 nm) 1 wt % gold-supported ceria nanoparticles generate oxygen from water (10.5 μmol·h–1) more efficiently than the standard WO3 (1.7 μmol·h–1) even under UV irradiation (9.5 μmol·h–1). This remarkable photocatalytic activity arises from a novel preparation method to reduce the particle size of ceria (5 nm) by means of electrostatic binding of Ce4+ to alginate gel, subsequent supercritical CO2 drying, and calcination. The low loading of Au is crucial for the observed high catalytic activity.