A bi-overlayer type plasmonic photocatalyst consisting of mesoporous Au/TiO sub(2) and CuO/SnO sub(2) films separately coated on FTO

• Published in: Physical chemistry chemical physics : PCCP Vol. 17; no. 27; pp. 18004 - 18010
• Main Authors: Naya, Shin-ichi, Kume, Takahiro, Okumura, Nozomi, Tada, Hiroaki
• Format: Journal Article
• Language: English
• Published: 01.07.2015
• Subjects: CATALYSTS; Clusters; Coating; COATINGS; COPPER OXIDE; Gold; OXIDES; Photocatalysis; POROSITY; Tin dioxide; TIN OXIDE; Tin oxides; TITANIUM DIOXIDE
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c5cp01111f

The principal purpose of this study is to present a new design for preparing highly active immobilized gold nanoparticle-based plasmonic photocatalysts. Gold nanoparticles were loaded on rutile TiO sub(2) particles with a mean size of 80 nm (Au/TiO sub(2)) by the deposition precipitation method. The surface of SnO sub(2) particles with a mean size of 100 nm was modified by copper(ii) oxide clusters (CuO/SnO sub(2)) with the loading amount ( Gamma /Cu ions nm super(-2)) precisely controlled by the chemisorption-calcination cycle technique. Two mesoporous overlayers of Au/TiO sub(2) and CuO/SnO sub(2) were coated side by side on glass substrates with a fluorine-doped tin oxide film (FTO) using the doctor blade method (Au/mp-TiO sub(2)|FTO|CuO/mp-SnO sub(2)). As test reactions for assessing the visible-light activity, we carried out gas-phase decomposition of acetaldehyde and liquid-phase oxidation of alcohol. In each reaction, this bi-overlayer type catalyst shows a high level of visible-light activity much exceeding those of Au/TiO sub(2) particles and a Au/mp-TiO sub(2)|FTO mono-overlayer type catalyst [J. Phys. Chem. C, 2014, 118, 26887]. To confirm the origin of the striking visible-light activity, we studied the electrocatalytic activity of CuO/mp-SnO sub(2)|FTO electrodes for the oxygen reduction reaction (ORR). Both the visible-light activity of Au/mp-TiO sub(2)|FTO|CuO/mp-SnO sub(2) and the electrocatalytic activity of CuO/mp-SnO sub(2)|FTO for ORR strongly depend on the Gamma value. A good positive correlation has been found between the visible-light activities and the electrocatalytic activity for ORR. The striking activity of the present bi-overlayer type catalyst can be attributed to the efficient and long-range charge separation by the vectorial electron transport (Au(oxidation sites) arrow right TiO sub(2) arrow right FTO, SnO sub(2) arrow right CuO(reduction sites)) and the excellent electrocatalytic activity of the CuO clusters.