Titania and Pt/titania aerogels as superior mesoporous structures for photocatalytic water splitting

The highly porous, three-dimensionally well-connected through-pore structure of TiO2 aerogels is proven a superior material form for applications in photocatalytic water splitting for hydrogen production. At the reaction temperature of 30 degrees C, the specific hydrogen evolution rate achieved by the TiO2 aerogel is 3.40 and 9.63 times those obtained by hydrothermally prepared TiO2 nanocrystals and commercial P25 TiO2 nanoparticles, respectively. Decoration of Pt nanocrystals onto the backbone of the TiO2 aerogel leads to a one-order of magnitude improvement in hydrogen evolution rate over the plain TiO2 aerogel. Two methods are developed for the Pt decoration: a polyol process and an immersion-calcination-reduction process. The latter produces smaller sized Pt nanocrystals of around 1.9 nm, versus 4.7 nm from the polyol process, and achieves the same level of maximum specific hydrogen evolution rates as the polyol process at only a 1/10 Pt loading.