Preparation of Au-CeO2 Nanocubes as a New SERS Substrate and Efficient Detection of Organic Compounds

Surface-enhanced Raman scattering (SERS) is extensively employed for detecting organics, where its sensitivity and selectivity are strongly influenced by the properties of the SERS substrates. In this work, a simple hydrothermal synthesis followed by a subsequent reduction was used to prepare Au-CeO2 composite nanocubes as a new SERS substrate, in which the side length of the CeO2 cubes was 20~30 nm and the diameter of the Au nanoparticles was 5~25 nm. Using methylene blue (MB) and crystal violet (CV) as probe molecules, the lowest detection limit (LDL) of methylene blue (MB) on the Au-CeO2 composite nanocubes substrate was 10−7 M, and the maximum SERS enhancement factor (EF) was 2.6 × 105. As a result, the lowest detection limit (LDL) of crystal violet (CV) was 10−7 M, and the maximum enhancement factor (EF) was 3.7 × 104. The above results proved that the Au-CeO2 composite nanocubes had a quite good Raman enhancement effect, which could be used as a SERS substrate. Finally, a Raman enhancement mechanism is proposed for the Au-CeO2 nanucubes.