Fig. 2: Experimental setup and characterization of pristine, Nafion-coated, and Au-decorated graphene.

a Magnified scheme and real image of the microfluidic channel device illustrating the inlet and outlet of the solution. b Raman spectroscopy of pristine, Nafion-coated, and Au-decorated graphene. The peaks show that the graphene is not influenced by Nafion coating or Au decoration. OM images of c pristine graphene, d Nafion-coated graphene, and e Au-decorated graphene. f TEM image of CVD grown pristine graphene. The inset shows the SAED patterns of pristine graphene. g Cross-sectional SEM image of Nafion-coated graphene. h TEM image of Au-decorated graphene. The inset shows the SAED patterns of Au-decorated graphene.