A composite prepared from gold nanoparticles and a metal organic framework (type MOF-74) for determination of 4-nitrothiophenol by surface-enhanced Raman spectroscopy

Core-shell nanoparticles (NPs) consisting of a gold core and a metal-organic framework shell (type MOF-74) were synthesized via one-pot synthesis. The NPs exhibit highly sensitive and stable SERS activity for the detection of 4-nitrothiophenol, with a specific band at 1337 cm(-1). The method has a linear response in 0.10-10 mu mol.L-1 analyte concentration range and a lower detection limit of 69 nmol.L-1. The potential application of this novel SERS substrate was evaluated by two model reactions involving 4-nitrothiophenol. The first involves in-situ SERS monitoring of the surface plasmon-induced nitration of aromatic rings without adding conventional acid catalyst. The second involves the photocatalytic reduction of 4-nitrothiophenol to 4-thioaminophenol in the presence of Au/MOF-74 under 785-nm laser irradiation. The plasmon-assisted dimerization of 4-nitrothiophenol to form 4,4-dimercaptoazobenzene can also be monitored simultaneously.