Effect of Reaction Conditions on the Characterization of Plasmon-Driven Surface Catalytic Reduction Reaction for Para-nitroaniline in a Liquid Condition

Abstract

Plasmon-driven–coupling reactions through nitro reduction or amino oxidation have been widely reported in the literature. This article studies the functional groups, reaction environment, and the effect of the molecular probe concentration on the coupling reaction using a surface-enhanced Raman spectroscopy (SERS) detection technique. First, we illustrate a sequence of nitro reduction and amino oxidation reactions under the same reaction conditions. Secondly, the relationships between the characterization phenomenon and the variables were studied by adjusting both the pH of the solution, the laser exposure time, and the concentration of the molecular probe in the reaction. We also performed the SERS detection on the product solution in liquid environments, indicating that p,p′-dimercaptoazobenzene (DAAB) is stable in the reaction system. There was no reverse reaction present, and no further polymerization was performed. This study demonstrates that the chemical reaction process is stable in plasmon-catalyzed reactions and serves as a starting point for future fluorescent probe studies with pH-regulated reactions.