Photocatalytic production of hydrogen from methanol and saccharides using carbon nanotube-TiO sub(2) catalysts

Carbon nanotube-titanium dioxide composite materials were produced by two routes: hydration-dehydration and one-pot oxidation. Au, Pt, Ir and Pd were loaded on TiO sub(2)-based materials by an incipient wetness method. The resulting materials were calcined and afterwards reduced at two distinct temp...

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Bibliographic Details
Published in:Applied catalysis. B, Environmental Environmental, 2015-11, Vol.178, p.82-90
Main Authors: Silva, Claudia G, Sampaio, Maria J, Marques, Rita RN, Ferreira, Liliana A, Tavares, Pedro B, Silva, Adrian MT, Faria, Joaquim L
Format: Article
Language:English
Subjects:
Catalysis
Catalysts
Methyl alcohol
Nanostructure
Photocatalysis
Platinum
Saccharides
Titanium dioxide
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Summary:Carbon nanotube-titanium dioxide composite materials were produced by two routes: hydration-dehydration and one-pot oxidation. Au, Pt, Ir and Pd were loaded on TiO sub(2)-based materials by an incipient wetness method. The resulting materials were calcined and afterwards reduced at two distinct temperatures, 473 and 673 K. Characterization was carried out by temperature programmed desorption, infrared and UV-Vis spectroscopy, N sub(2) adsorption, SEM and TEM. Compared with reference TiO sub(2), composite catalysts presented increased activity for photocatalytic production of H sub(2) from methanol solutions. The highest activity was obtained for the Pt-loaded composite produced by the one-pot synthesis method, with 485 mu mol of H sub(2) being generated after two hours of irradiation, contrasting with 205 mu mol of H sub(2) obtained using Pt/TiO sub(2). This synergic effect was discussed in terms of the action of carbon nanotubes as dispersing media for TiO sub(2) particles as well as their action as photosensitizers. The relative efficiency of the catalysts was related to the work function of each metal and the sizes of the metal nanoparticles. H sub(2) generation from photocatalytic reforming of saccharides, namely arabinose, glucose, fructose and cellobiose was performed using TiO sub(2) and CNT-TiO sub(2) based catalysts. The relative efficiency of H sub(2) production from these biomass-derived compounds has been discussed based on their structural arrangement, H:C ratio and availability of alpha -hydrogens.
ISSN:0926-3373
DOI:10.1016/j.apcatb.2014.10.032