Photocatalytic reduction of methyl orange on Au/TiO2 semiconductors
The photocatalytic reduction of Methyl Orange (MO) in aqueous solution by gold nanoparticles deposited by deposition–precipitation (DP) method on Degussa P25 was studied as a function of gold content. A shift to the red region on the UV spectra from 3.2 (Degussa P25) to 2.9–2.8 eV on the Au/TiO2 materials was observed by the presence of gold. High photocatalytic activity for the MO reduction using lamps of low energy UV–Vis emission (λ = 365, 418, 435 nm) was obtained for the Au/TiO2 semiconductors, improving the rate constant of reduction in a factor up to 3.2 times compared to TiO2 P25 used as reference. These results evidence a very important role of gold in photoreduction reactions for organic compounds, in this particular case for the reduction of MO.
Graphical abstractGold deposited on Degussa P5 commercial semiconductor enhances the photocatalytic activity for the Methyl Orange Reduction.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Gold enhances the MO reduction on Au/TiO2 semiconductors. ► Improvement of 3.2 times than TiO2P25 in the photoreduction of methyl orange. ► Red shift to the visible region on TiO2 induced by gold deposition. ► Zero kinetic order in the photoreduction for diluted solutions of methyl orange.
Journal: Catalysis Communications - Volume 21, 5 May 2012, Pages 72–76