Flexible SERS substrate In-situ monitoring of SPR-induced P-aminothiophenol dimerization

Abstract

Surface-enhanced Raman spectroscopy (SERS) is an efficient technique for in-situ molecular investigation that is highly sensitive and has the ability to provide extensive fingerprint information. Additionally, the surface plasmons on the SERS substrate can also simultaneously induce the catalytic reaction. P-aminothiophenol (PATP) is a crucial model molecule utilized in SERS catalytic reactions. Through dimerization, PATP induced by the plasmon effect can produce 4,4’-dimercaptoazobenzene (DMAB). Here, a flexible SERS substrate with a monolayer of Au nanoparticles on polydimethylsiloxane (PDMS) is prepared and used for monitoring the dimerization of PATP. In the experiment, the SERS substrate is inverted, the side with Au nanoparticles monolayer is kept in contact with the PATP solution directly, and the laser is irradiated from the backside of the flexible substrate. The effects of Ag+ and oxygen concentrations on the reaction are investigated. This work paves the way for SERS methodology in in-situ monitoring of other liquid-phase catalytic reactions.