Photocatalytic H₂ Production Using Pt-TiO₂ in the Presence of Oxalic Acid: Influence of the Noble Metal Size and the Carrier Gas Flow Rate

Photocatalytic H₂ Production Using Pt-TiO₂ in the Presence of Oxalic Acid: Influence of the Noble Metal Size and the Carrier Gas Flow Rate

The primary objective of the experiments was to investigate the differences in the photocatalytic performance when commercially available Aeroxide P25 TiO₂ photocatalyst was deposited with differently sized Pt nanoparticles with identical platinum content (1 wt%). The noble metal deposition onto the...

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Bibliographic Details
Published in:Materials Vol. 7; no. 10; pp. 7022 - 7038
Main Authors: Kmetykó, Ákos, Mogyorósi, Károly, Gerse, Viktória, Kónya, Zoltán, Pusztai, Péter, Dombi, András, Hernádi, Klára
Format: Journal Article
Language:English
Published: Switzerland MDPI AG 17-10-2014
MDPI
Subjects:
Acids
Chemistry
Deposition
Efficiency
Electron microscopes
Gas flow
H2 production
Informatics
Irradiation
Nanoparticles
Noble metals
Oxalic acid
Particle size
Photocatalysis
Platinum
Pt nanoparticles
size dependent activity
Surfactants
TiO2
Titanium dioxide
Hungary
H2 production
Pt nanoparticles
size dependent activity
oxalic acid
TiO2
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Summary:The primary objective of the experiments was to investigate the differences in the photocatalytic performance when commercially available Aeroxide P25 TiO₂ photocatalyst was deposited with differently sized Pt nanoparticles with identical platinum content (1 wt%). The noble metal deposition onto the TiO₂ surface was achieved by chemical reduction (CRIS) or by mixing chemically reduced Pt nanoparticle containing sols to the aqueous suspensions of the photocatalysts (sol-impregnated samples, CRSIM). Fine and low-scale control of the size of resulting Pt nanoparticles was obtained through variation of the trisodium citrate concentration during the syntheses. The reducing reagent was NaBH₄. Photocatalytic activity of the samples and the reaction mechanism were examined during UV irradiation (λ = 365 nm) in the presence of oxalic acid (50 mM) as a sacrificial hole scavenger component. The H₂ evolution rates proved to be strongly dependent on the Pt particle size, as well as the irradiation time. A significant change of H₂ formation rate during the oxalic acid transformation was observed which is unusual. It is probably regulated both by the decomposition rate of accumulated oxalic acid and the H⁺/H₂ redox potential on the surface of the catalyst. The later potential is influenced by the concentration of the dissolved H₂ gas in the reaction mixture.
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content type line 23
ISSN:1996-1944
1996-1944
DOI:10.3390/ma7107022