In situ SERS monitoring of photocatalytic organic decomposition using recyclable TiO2-coated Ag nanowire arrays

Recently, semiconductor and noble metal complex nanomaterials have attracted ever-increasing attention because of the realization of multiple functionalities in a single entity. In this study, Ag-TiO2 core-shell nanocomposites were synthesized by hydrolysis of butyl titanate on the surface of Ag nanowires. Due to efficient electron transfer at the Ag-TiO2 interface, the as-prepared nanocomposites exhibit much higher photocatalytic activity than bare TiO2 films, as demonstrated by the enhanced photodegradation rate of R6G and methyl blue molecules. In the meanwhile, such nanocomposites serve as a high-sensitivity surface-enhanced Raman scattering (SERS) substrate for in situ monitoring of the photocatalytic decomposition reaction, and the substrate is recyclable due to its self-cleaning function. Full-wave numerical calculations reveal that the improved photocatalysis and SERS efficiencies are attributed to the largely enhanced electromagnetic near-field in the nanocomposites. Our results point out that bifunctional semiconductor-metal hybrids hold great promise for simultaneously detecting and decomposing organic pollutants in the environment. (C) 2014 Elsevier B.V. All rights reserved.