Hydrogarnet-derived Rh/TiO₂ catalysts with a low rhodium content for a photocatalytic hydrogen production

A novel protocol for the preparation of Rh-decorated TiO2 photocatalysts with the rhodium content of 0.01-1.0 wt% has been developed based on the deposition of the low-soluble hydrogarnet type salt Ca-3[Rh(OH)(6)](2). Under 380-nm irradiation in water-ethanol mixtures the photoinduced reduction of Ca-3[Rh(OH)(6)](2)/TiO2 results in the formation of highly active Rh/TiO2 photocatalysts with nanoparticulated rhodium co-catalyst preferably attached to the surface of anatase particles. The catalysts generate up to 21 mol of H-2 per gram of rhodium per hour via a photocatalytic hydrogen evolution reaction (HER) outperforming the activity of the analogous materials reported to date.