Control of Surface Plasmon Resonance of Au/SnO2 by Modification with Ag and Cu for Photoinduced Reactions under Visible‐Light Irradiation over a Wide Range |
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Authors: | Dr Atsuhiro Tanaka Dr Keiji Hashimoto Dr Hiroshi Kominami |
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Institution: | 1. Department of Applied Chemistry, Faculty of Science and Engineering, Kindai University, Kowakae, Higashiosaka, Osaka, Japan;2. Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan |
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Abstract: | Gold particles supported on tin(IV) oxide (0.2 wt % Au/SnO2) were modified with copper and silver by the multistep photodeposition method. Absorption around λ=550 nm, attributed to surface plasmon resonance (SPR) of Au, gradually shifted to longer wavelengths on modification with Cu and finally reached λ=620 nm at 0.8 wt % Cu. On the other hand, the absorption shifted to shorter wavelength with increasing amount of Ag and reached λ=450 nm at 0.8 wt % Ag. These Cu‐ and Ag‐modified 0.2 wt % Au/SnO2 materials (Cu‐Au/SnO2 and Ag‐Au/SnO2) and 1.0 wt % Au/SnO2 were used for mineralization of formic acid to carbon dioxide in aqueous suspension under irradiation with visible light from a xenon lamp and three kinds of light‐emitting diodes with different wavelengths. The reaction rates for the mineralization of formic acid over these materials depend on the wavelength of light. Apparent quantum efficiencies of Cu‐Au/SnO2, Au/SnO2, and Ag‐Au/SnO2 reached 5.5 % at 625 nm, 5.8 % at 525 nm, and 5.1 % at 450 nm, respectively. These photocatalysts can also be used for selective oxidation of alcohols to corresponding carbonyl compounds in aqueous solution under visible‐light irradiation. Broad responses to visible light in formic acid mineralization and selective alcohol oxidation were achieved when the three materials were used simultaneously. |
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Keywords: | gold nanoparticles photochemistry supported catalysts surface plasmon resonance |
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