Surface enhanced Raman spectroscopy based on Ag@mZrO2@Ag nanocomposites: Sensing and photocatalytic reduction of chromium(VI)

• An Ag@mZrO 2 @Ag nanocomposite was developed for SERS sensing Cr(VI) • They combined with excellent SERS activity and photocatalytic property. • They could sense Cr(VI) at low concentration of 10 −8 M. • They were used to in situ SERS monitor the photoreduction of Cr(VI). In situ and real time monitoring chemical reactions has been subjected to widespread concern in many areas. Herein, a novel and efficient SERS platform constructed from coating mesoporous ZrO 2 (mZrO 2 ) interlayer onto an Ag core and subsequently depositing outer Ag nanoparticles was successfully fabricated. The Ag@mZrO 2 @Ag nanocomposite exhibited an ultrahigh SERS sensitivity as well as remarkably photocatalytic property assisted by a plenty of Ag nanoparticles on the outer surface and photoactive mZrO 2. Experimental results proved the limit of detection of Cr(VI) was down to 10 −8 M and the good linearity dependence of SERS intensities on the logarithm of concentration (R 2 = 0.93) was obtained. Moreover, a simple SERS method was used to in situ monitor the photocatalytic reduction of Cr(VI) under visible light (λ > 420 nm). In addition, as practical SERS substrates, Ag@mZrO 2 @Ag nanocomposites presented outstanding signal reproducibility and remarkable storing stability. As a consequent, this study came up with a new strategy for in situ monitoring photocatalytic reactions and will be possibly utilized in chemical sensing and ecological restoration in the future.