Plasmonic MoO 2 nanospheres assembled on graphene oxide for highly sensitive SERS detection of organic pollutants

Abstract

The molybdenum oxide and graphene oxide (MoO 2 /GO) nanocomposite has been fabricated via simple hydrothermal assisted synthesis using Mo and MoO 3 as precursors. The MoO 2 nanospheres with porous hollow structure are assembled onto GO nanosheets. Profiting from the plasmonic effects of MoO 2 and synergistic effect of MoO 2 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 × 10 7 , which is the best among the semiconductor-based SERS materials. For practical application, the MoO 2 /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.