Aluminum sheet-induced porous zinc oxide nanosheets decorated with silver nanoparticles for ultrasensitive SERS sensing of crystal violet

Abstract

In this work, porous zinc oxide (ZnO) nanosheets induced by Al sheets were fabricated (Al/ZnO) via a simple hydrothermal method for the first time. Subsequently, various sizes of silver nanoparticles (AgNPs) were in situ decorated on Al/ZnO and a highly sensitive surface enhancement Raman scattering (SERS) substrate Al/ZnO/Ag was prepared. The strong synergistic effect between AgNPs and Al/ZnO was confirmed by UV-vis diffuse reflectance and X-ray photoelectron spectroscopy (XPS). Interestingly, the substrate exhibited outstanding SERS response towards crystal violet (CV, a carcinogen used in external disinfectants) due to the high electromagnetic enhancement effect generated by AgNPs on the large amount of tip areas in Al/ZnO as well as the charge transfer among the components. The results showed that Al/ZnO/Ag (Ag content: 1.51 wt%) can detect the SERS signal of CV molecules at a low concentration of 1 × 10⁻¹³ mol L⁻¹, and the analytical enhancement factors (AEF) can reach 2.45 × 10⁸. In addition, the Raman activity of Al/ZnO/Ag hardly changed within 42 days or after seven cycles. Moreover, the Al/ZnO/Ag substrate displayed high sensitivity, good uniformity and repeatability for the SERS detection of CV, and it showed good selectivity towards CV in actual water samples. The results demonstrate that the low-cost and portable Al/ZnO/Ag substrate has excellent practical ability for the trace detection of CV.