Surface Plasmon Resonance-Triggered Local Electromagnetic Field Advances Photocatalytic and Photoelectrochemical Performance of Plasmonic Metal/Semiconductor Composite

Introducing plasmonic metallic nanoparticles into semiconductor photocatalysts is a promising strategy to achieve high solar energy conversion. Plasmonic metallic nanoparticles can transfer energy to adjacent semiconductors in a variety of ways, but the contribution of each pathway to the photocatalytic process still needs to be made clear. In this work, we designed a composite of Au@SiO2/SnO2 to separately study the impact of local electromagnetic field (LEMF) induced by surface plasmon resonance (SPR) of metal nanoparticles on the photocatalytic and photoelectrochemical performance of semiconductors by excluding other charge/energy transfer pathways. The result from photocatalytic degradation and photoelectrochemical measurement indicates that LEMF around Au@SiO2 can promote the formation of electron–hole pairs in nearby SnO2 without the overlap between the metallic SPR band and the semiconductor absorption spectrum. This promotion effect is closely related to the distance between SnO2 and Au@SiO2, which almost disappears when the gap between the two components is more significant than 10 nm. This study provides a perspective method to explore the energy transfer between plasmonic nanoparticles and semiconductors