Ultrasmall Ag Clusters Modified W₁₈O₄₉ Ultrathin Nanowires for Sensitive Surface Enhanced Raman Spectroscopy Detection

Abstract

Though plasmonic Au and Ag nanocrystals are predicted as the best substrate materials for surface enhacned Raman spectrum (SERS), realization of their large‐scale applications is hindered by the high cost. How to reduce the amount of noble‐metals and achive excellent SERS enhancement factor is an urgent issue to be solved. Herein, a general freeze‐drying‐assisted in‐situ reduction method for the large‐scale synthesis of ultrathin Ag clusters modified oxygen vacancies‐rich W18O49 ultrathin nanowires based on the intrinsic reducibility of the oxygen vacancies contained in crystal lattice has been reported, which realizes high density loading of Ag clusters without external reductants and protective additives. As a new SERS substrate, the ultrathin Ag clusters loaded W18O49 ultrathin nanowires not only save a lot of noble metals, but also show an unexpected ultrahigh SERS sensitivity, which EF is up to 4.3×107 and lowest detection limit for Rhodamine 6G is as high as 10−10 M. The Ag clusters modified W18O49 ultrathin nanowires also exhibit excellent universality for a series of highly concerned hazardous chemicals in practical detection, such as bisphenol A, melamine, 2,4‐dichlorophenol and butyl hydroxy anisd.