Size-Controlled Electron Transfer and Photocatalytic Activity of ZnO-Au Nanoparticle Composites

Jaeil Lee †, Hyeong Seop Shim ‡, Myeongsoon Lee †, Jae Kyu Song *‡, and Dongil Lee *†J. Phys. Chem. Lett., 2011, 2 (22), pp 2840–2845

http://pubs.acs.org/doi/abs/10.1021/jz2013352

Abstract

This Letter describes size-controlled photocatalytic activity of ZnO nanoparticles coated with glutathione-protected gold nanoparticles with diameters of 1.1, 1.6, and 2.8 nm. The photocatalytic activity of the ZnO–Au composites was found to increase with increasing gold size for both oxidative and reductive catalytic reactions. Photoluminescence decay dynamics of the composites showed that the electron-transfer rate from the photoexcited ZnO to gold nanoparticle also increased as the gold size increased. These results demonstrate that the photogenerated electron transfer and the resulting catalytic activity of the composites can be controlled by the size of the mediating gold capacitors.