In situ surface-enhanced raman spectroscopy study of plasmon-driven catalytic reactions of 4-nitrothiophenol under a controlled atmosphere

We demonstrate the plasmon-driven catalytic reactions of 4-nitrothiophenol (4NTP) on a single Ag microsphere by an in situ surface-enhanced Raman spectroscopy (SERS) technique. The highly SERS-active hierarchical Ag structures served as an ideal platform to study plasmon-driven catalytic reactions. This single-particle surface-enhanced Raman spectroscopy (SP-SERS) technique coupled with inbuilt apparatus allow us to study the impact of reaction atmospheres and laser power on the rate of dimerization and reduction of 4NTP. Contrary to that found in previous studies, 4NTP could be transformed into 4-aminothiophenol under H₂O or H₂ atmosphere. The broadening and splitting of the ν(C-C) band during the reaction results from the frequency shift of the ν(C-C) band that arises from different products. Our results suggest that the SP-SERS technique is ideally suited to study plasmon-driven catalytic reactions because of the possibility to monitor the reaction under controlled atmospheres in real time.