Fast and efficient hydrogen generation catalyzed by cobalt talc nanolayers dispersed in silica aerogel

Cobalt talc nanolayers dispersed in silica aerogel constitute an active nanocomposited material with outstanding catalytic properties for the generation of hydrogen by ethanol steam reforming at low temperature. Delamination of talc particles into individual nanolayers of ca. 1.8 nm thick readily occurs under the reforming conditions, which results in a strong enhancement of the exposed catalytic active area. The presence of aerogel assures the immobilization of the talc nanolayers resulting from the delamination while maintaining an excellent mass transfer of products and reactants to the surface of the talc nanolayers. A fast and reversible surface activation for the steam reforming of ethanol occurs at 580-590 K under the reforming conditions. Magnetic characterization and in situ X-ray photoelectron spectroscopy (XPS) show the non-reversible formation of metal cobalt ensembles during activation, which escape HRTEM detection. This material appears as a good candidate for on-board hydrogen generation from ethanol-water mixtures for mobile and portable fuel cell applications.