Localized Surface Plasmon Resonance Induced Band Gap Regulation Governing the Excellent Photocatalytic Performance of Ag/g-C₃N₄ Heterostructure.

Abstract

It is an efficient mode to optimize photocatalytic performance of semiconductors by the localized surface plasmon resonance (LSPR) effect through constructing composites with noble metal nanoparticles, nevertheless, the understanding for the essential mechanism, especially the LSPR effect on band gap engineering or free radicals, is not clear. Herein, Ag nanoparticles (Ag NPs) were decorated on popular used semiconductors, graphitic carbon nitride (g-C₃N₄), through a microemulsion route. As expected, Ag/g-C₃N₄ hybrid materials demonstrated outstanding photocatalytic decomposition of organic dyes, including methyl orange, phenol and rhodamine B, in which the photocatalytic efficiency of the composite with the optimal ratio of Ag content was 3.37 times higher than that of pristine sample. The mechanism for the better photocatalytic action was attributed to the localized surface plasmon resonance (LSPR) effect, narrow band gap and low valance band position originated from Ag NPs, which resulted in superior visible-light adsorption and the formation of _OH with strong oxidation. As well, because of the synergy between Ag NPs and g-C₃N₄, faster separation of the photogenerated charges and efficiently utilization of the ·OH and ·O-₂ generated from hole and electron are realized simultaneously. Ultimately, our results offer a extremely understanding of superior photocatalytic property caused by the LSPR effect.