SERS detection of 1,4-bis(2-aminoethyl)piperazine functionalized GO (AEP-GO) on X60 carbon steel surface in 15% HCl solution.

In this study, a silver nanoparticle anchored transparent tape sensor was used to detect 1,4-bis(2-aminoethyl)piperazine functionalized GO (AEP-GO) adsorbed on carbon steel surface utilizing the surface-enhanced Raman scattering (SERS) technique. SERS detection enabled the extreme amplification of Raman signals emitted by inhibitor molecules in order to describe their adsorption behavior on metallic/alloy surfaces. The strong corrosion inhibition performance of AEP-GO against carbon steel corrosion in 15 % HCl solution was proven by weight loss, electrochemical measurements and surface characterization techniques in a previous study. The SERS analysis showed the Raman peaks intensity of AEP-GO on the carbon surface gradually increases with increasing AEP-GO concentration. The increasing intensity with concentration correlated well with the previously reported weight loss and electrochemical results. DFT calculation was also carried out to understand the nature of interaction between the adsorbed AEP-GO molecules and the silver nanoparticles. The AEP-GO_Ag adduct's optimized structure reveals the silver metals approached the oxygen atom at the GO epoxy group in AEP-GO rather than the oxygen atoms at the carbonyl and hydroxyl groups. With no restrictions on substrate materials, the fabricated SERS sensor created in this study can be employed as a versatile sensor to characterize corrosion adsorption processes on metal surfaces.