title: Super-resolution mapping of photogenerated electron and hole separation in single metal-semiconductor nanocatalysts.
abstract: Metal-semiconductor heterostructures are promising visible light photocatalysts for many chemical reactions. Here, we use high-resolution superlocalization imaging to reveal the nature and photocatalytic properties of the surface reactive sites on single Au-CdS hybrid nanocatalysts. We experimentally reveal two distinct, incident energy-dependent charge separation mechanisms that result in completely opposite photogenerated reactive sites (e(-) and h(+)) and divergent energy flows on the hybrid nanocatalysts. We find that plasmon-induced hot electrons in Au are injected into the conduction band of the CdS semiconductor nanorod. The specifically designed Au-tipped CdS heterostructures with a unique geometry (two Au nanoparticles at both ends of each CdS nanorod) provide more convincing high-resolution single-turnover mapping results and clearly prove the two charge separation mechanisms. Engineering the direction of energy flow at the nanoscale can provide an efficient way to overcome important challenges in photocatalysis, such as controlling catalytic activity and selectivity. These results bear enormous potential impact on the development of better visible light photocatalysts for solar-to-chemical energy conversion.
authors.affiliation: Ames Laboratory, U.S. Department of Energy, and Department of Chemistry, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Ha
authors.forename: T Purnima A
authors.initials: TP
authors.lastname: Ruberu
authors.forename: Rui
authors.initials: R
authors.lastname: Han
authors.forename: Bin
authors.initials: B
authors.lastname: Dong
authors.forename: Javier
authors.initials: J
authors.lastname: Vela
authors.forename: Ning
authors.initials: N
authors.lastname: Fang