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

Materials

Ákos Kmetykó¹  Károly Mogyorósi¹  Viktória Gerse¹  Zoltán Kónya²  Péter Pusztai²  András Dombi¹  Klára Hernฝi¹ 

[1] Research Group of Environmental Chemistry, Institute of Chemistry, Faculty of Sciences and Informatics, University of Szeged, H-6720 Szeged, Tisza L. krt. 103., Hungary; E-Mails:;Department of Applied and Environmental Chemistry, Faculty of Sciences and Informatics, University of Szeged, H-6720 Szeged, Rerrich tér 1., Hungary; E-Mails:

关键词: TiO₂;    H₂ production;    Pt nanoparticles;    size dependent activity;    oxalic acid;   

DOI  :  10.3390/ma7107022

来源: mdpi

【 摘 要 】

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 in situ 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_max = 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.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.