Construction of ultra-sensitive surface-enhanced Raman scattering substrates based on 3D graphene oxide aerogels

Graphene-enhanced Raman scattering was an attractive Raman enhanced technique and has made remarkable progress in food safety, environmental monitoring, and bioanalysis. However, novel three-dimensional (3D) graphene materials had not been explored as SERS substrates. Here, 3D graphene oxide aerogels (GOA) were constructed and used as ultra-sensitive SERS substrates. In a hydrothermal environment, GO nanosheets were self-assembled into GO hydrogel and then combined with freeze-drying to obtain GOA. The optimized GOA had a high SERS enhancement factor (3.1 × 10⁴) and a low detection limit (10⁻⁸ M) for the dye molecules. The excellent SERS effect was attributed to the large specific surface area of GOA, which facilitated molecular adsorption and formed abundant 3D hot spots. In addition, benefiting from the electron transfer promoted by the reduction of the band gap energy, synergistically enhanced the SERS effect. This work expands the applications of graphene oxide aerogels and provides valuable insights for designing novel 3D SERS substrates.