Photocatalytic hydrogen production using TiO2-Pt aerogels

TiO2-Pt aerogel composites have been synthesized by mixing sol-gel titania with Pt colloidal suspensions followed by supercritical drying. The highest specific surface achieved with these materials ranged between 550 and 600 m(2) g(-1) before annealing and stayed relatively high, i.e. 162 m(2) g(-1), after calcination. The concentration of Pt nanoparticles ranged between 0.3 and 1.0 wt.% while their size ranged between 5.75 and 6.5 nm. These composites were employed as photocatalysts for room-temperature photocatalytic reforming of ethanol and hydrogen production. The highest hydrogen production rate, 7.2 mmol H-2 h(-1) g(-1), was obtained in the case of the smallest and most concentrated metal nanoparticles underlying the importance of the number of active sites on the TiO2-Pt composites. This rate of hydrogen production is relatively high and reflects the relatively high specific surface of the employed photocatalysts. (C) 2013 Elsevier B.V. All rights reserved.