Self-cleaning SERS membrane for reusable and ultrasensitive molecular detection via integrating graphitic-carbon-nitride nanosheets and Ag nanospheres into hierarchical graphene layers that covered with graphitic-carbon-nitride quantum-dots

摘要

Self-cleaning ability is an attractive parameter for fabricating practical surface enhanced Raman scattering (SERS) substrates. Thus, it is an important issue for searching suitable materials to decompose molecules inside SERS "hot spots". Here we fabricate a flexible CNs/AgNSs@CNQDs-GLs SERS membrane for visible-light derived reusable molecular detection, via integrating graphitic-carbon-nitride nanosheets (CNs) and Ag nanospheres (AgNSs) into graphene layers that covered with graphitic-carbon-nitride quantum-dots (CNQDs-GLs). This membrane exhibits strong SERS activity due to the high pre-concentration ability to analytes via the delocalized pi-bond, and well-rounded self-cleaning performance due to: i) the bottomed CNQDs-GLs as photocatalytic platforms degrade molecules inside nanogaps; and ii) the CNs on AgNSs@CNQDs-GLs surfaces decompose molecules outside nanogaps. This reusable membrane can be used for rhodamine B (RhB) or methylene blue (MB) fully-recovered circle-detection with a limit of 10(-14) M. The practicability of this membrane is shown by detection-photodegradation cycle-runs of 4-chlorophenol, and no obvious performance loss can be observed. Thus, this membrane provides an effective route to overcome one-off substrates or incomplete self-cleaning substrates, for developing green sensing techniques.