Visible-Light Plasmonic Enhancement of Catalytic Activity of Anisotropic Silver Nanoparticles

Synthesis of silver nanoparticles (AgNPs) in presence of copper salt (as the etchant) led to the formation of nanoparticle samples with different fractions of anisotropic particles. The proportion of anisotropic nanoparticles decreased with increase in ratio of precursor Cu salt in the preparation protocol. These AgNPs samples were found to catalyse p-nitrophenol reduction by glycerol and Fenton oxidation of methyl orange. The catalytic activity of these AgNPs samples for these reactions increased with the fraction of anisotropic nanoparticles in the catalyst samples. On conducting these reactions under cool white LED visible light, the catalytic activity of AgNPs catalyst samples increased by 2 to 3 times compared to that observed in dark. The photo-Fenton MO degradation catalytic activity obtained is among the best reported in literature. However, the order of the reaction did not change whether the reaction was conducted under visible light or in dark. Direct plasmonic catalytic mechanisms are proposed to explain the enhancement in reactivity under visible light.