1. High photocatalytic hydrogen production on Cu(II) pre-grafted Pt/TiO2.
- Author
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Dozzi, Maria Vittoria, Chiarello, Gian Luca, Pedroni, Matteo, Livraghi, Stefano, Giamello, Elio, and Selli, Elena
- Subjects
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PHOTOCATALYSTS , *HYDROGEN production , *COPPER catalysts , *PLATINUM catalysts , *TITANIUM dioxide , *METHANOL - Abstract
A series of Pt/Cu/TiO 2 photocatalysts, showing very high performance in photocatalytic hydrogen production from methanol/water vapour mixtures, were prepared under mild conditions by Cu(II) grafting on commercial P25 TiO 2 , with nominal Cu/TiO 2 ratios ranging from 0.05 to 0.5 wt.%, followed by 0.5 wt.% Pt nanoparticles deposition by the deposition-precipitation method in the presence of urea. The structural features of the so obtained materials were fully characterized by X-ray absorption spectroscopy, which provided information on the oxidation state of the two metals and on the metal–metal and metal-TiO 2 interactions, and by EPR analysis, which evidenced electron transfer phenomena involving copper under irradiation. The photocatalysts showed a volcano-shaped photoactivity trend in hydrogen production with increasing nominal Cu content, the maximum rate of H 2 evolution (27.2 mmol h −1 g cat −1 ) being attained with the photocatalyst containing 0.1 wt.% of copper. In this sample CuO nanoclusters appear to be intimately coordinated with surface Ti atoms in a surface structure that partially stabilizes pre-grafted copper in metallic form, possibly acting as an electron-transfer bridge at the interface between CuO nanoclusters and TiO 2 . Synergistic effects in H 2 photocatalytic production are clearly induced by the co-presence of grafted Cu nanoclusters and Pt nanoparticles on the TiO 2 surface, with the copper oxidation state switching under UV–vis irradiation, facilitating electron transfer to adsorbed protons. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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