The influences of graphene oxide (GO) and plasmonic Ag nanoparticles modification on the SERS sensing performance of TiO2 nanosheet arrays

A sensitive solid semiconductor-based surface-enhanced Raman spectroscopy (SERS) substrate can realize recyclable and portable detection of organic pollutants. In this paper, TiO 2 nanosheets (NSs) on FTO glass substrate were synthesized by a simple and controllable hydrothermal method , followed by decoration of plasmonic Ag nanoparticles (AgNPs), and further deposition of graphene oxide (GO). The GO and AgNPs co-modified TiO 2 substrate showed improved signal reproducibility, longer-term stability, and higher detection sensitivity than that of TiO 2 counterparts. Note that, the optimized TiO 2 -Ag-GO substrate can also be utilized to discriminate multiple organic pollutants with a portable Raman instrument. The limit of detection (LOD) for crystal violet (CV), rhodamine 6 G (R6G) and malachite green (MG) was 10 −9 M, 10 −8 M, and 10 −7 M, respectively. Moreover, the solid substrate was applied to discern low concentrations of CV residue (10 −8 M) on crayfish’s shell and thiram residue (10 −6 M) on grape skin. As a proof of concept, multiplex detections were also demonstrated. More significantly, the better photocatalytic degradation performance of the TiO 2 -Ag-GO makes the solid substrate reuse for 10 cycles. The solid SERS substrate may have great potential for practical applications and resource-confined detections.