Preparation of Au-loaded niobate nanosheets and their plasmon-driven photochemical reaction

Niobate nanosheets prepared by exfoliation of layered hexaniobate K(4)Nb(6)O(17) were sequentially decorated with two noble metal nanoparticles, gold and silver, through two-step photochemical reactions. First, cationic bis(ethylenediamine)gold(III) ions were electrostatically adsorbed on the anionic niobate nanosheets, and reduced to gold nanoparticles by UV excitation of the photocatalytically active niobate nanosheets. Then, the surface plasmon band of the photodeposited gold nanoparticles was excited with visible light, by which the silver cations introduced to the system together with citrate anions were reduced to silver nanoparticles. Spectroscopic and transmission electron microscopic observations indicated the formation of morphologically different silver nanoparticles, for example nanorods and core-shell particles. (C) 2011 Elsevier B.V. All rights reserved.