Plasmon-Driven Diazo Coupling Reactions of p-Nitroaniline via -NH2 or -NO2 in Atmosphere Environment

Plasmon-driven diazo coupling reaction of p-nitroaniline (PNA), containing both an amine group (-NH2) and a nitro group (-NO2), in ambient atmosphere environments remains unknown in experiments, on both metal nanoparticles and graphene-mediated metal nanostructures. Using the surface-enhanced Raman scattering (SERS) technique, we presented the surface coupling reactions of PNA under atmospheric environment, adsorbed on the Ag nanoparticle (AgNP) arrays, graphene-coated Ag nanoparticle (G/AgNPs) hybrids, and graphene-covered Ag nanowire (G/ AgNW) composites, respectively. It was found that PNAs were converted into 4,4'-diaminoazobenzene (DAAB) through a selective reduction reaction, rather than oxidized into 4,4'dinitroazobenzene (DNAB). These results may be useful for understanding the reaction mechanism for plasmon-driven chemical reactions of the molecules containing.both amine groups and nitro groups under ambient conditions.