Plasmonic MoO2 nanospheres assembled on graphene oxide for highly sensitive SERS detection of organic pollutants.

The molybdenum oxide and graphene oxide (MoO2/GO) nanocomposite has been fabricated via simple hydrothermal assisted synthesis using Mo and MoO3 as precursors. The MoO2 nanospheres with porous hollow structure are assembled onto GO nanosheets. Profiting from the plasmonic effects of MoO2 and synergistic effect of MoO2 and GO, this hybrid nanomaterial exhibits significantly enhanced surface enhanced Raman scattering (SERS) activity for organic pollutants. The detection limit for rhodamine 6G (R6G) is 1.0 × 10-9 M, and the maximum enhancement factor (EF) reaches up to 1.05 × 107, which is the best among the semiconductor-based SERS materials. For practical application, the MoO2/GO SERS substrates are also applied to detect Methylene blue (MB) in river water, and the detection limit (1.0 × 10-8 M) can be acquired. Pyrene is also chosen as probe molecule, and quantitative determination is achieved with detection limit of 1.0 × 10-7 M. These demonstrate the well feasibility for multi-molecule detection. Furthermore, the nanocomposite displays high stability, reproducible stability, and acid and alkali resistance. Graphical abstract.