Plasmonic Heating Plays a Dominant Role in the Plasmon-Induced Photocatalytic Reduction of 4-Nitrobenzenethiol

It is believed that plasmon-excited electrons from Ag and Au nanostructures can induce photochemical reactions. However, the influence of heat generated by nanoparticle (NP) hotspots during light irradiation was not systematically studied yet. To evaluate the role of plasmonic heating, we performed a surface-enhanced Raman spectroscopy study of the photocatalytic conversion of 4-nitrobenzenthiol to 4-aminobenzenthiol by metal NPs with different compositions and shapes having localized surface plasmon resonances (LSPRs) spanning the whole visible range. Our collective results based on temperature-dependent studies and multi wavelength analyses show that contrary to the previous reports, the photocatalytic reaction is not only determined by the excitation of LSPRs or by the NP material (Ag or Au) but also drastically dependent on the plasmon-induced heating. This work has strong implications for the development and engineering of novel plasmonic and photonic applications where the role of localized temperature must be considered.