Near-infrared photothermal conversion of polyoxometalate-modified gold nanorods for plasmon-enhanced catalysis

Abstract

Combining the high catalytic activity of polyoxometalates (POMs) and the near-infrared (NIR) photothermal property of gold nanorods (AuNRs), POM-modified AuNR composites were synthesized by ligand replacement and electrostatic adsorption. Such a combination has led to a type of unique plasmon-enhanced photothermal transformation catalysts for the selective oxidation of thioether derivatives in an aqueous system. The designed POM-modified AuNRs allowed the catalytic reaction to occur on the surface of the photothermal center. Under NIR laser irradiation, the higher local temperature caused by the photothermal conversion greatly improved the catalytic activity of the catalyst compared to external heating. The observed kinetic constant under photothermal conditions was more than five times that under external heating conditions. Moreover, these catalysts, which show structural stability and catalytic stability under NIR photothermal environment can not only maintain a high photothermal conversion efficiency but also can sustain the original catalytic activity even after 10 catalytic cycles.