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Super-Resolution Mapping of Photogenerated Electron and Hole Separation in Single Metal-Semiconductor Nanocatalysts

TitleSuper-Resolution Mapping of Photogenerated Electron and Hole Separation in Single Metal-Semiconductor Nanocatalysts
Publication TypeJournal Article
Year of Publication2014
AuthorsHa, JW, Ruberu, TPA, Han, R, Dong, B, Vela, J, Fang, N
JournalJournal of the American Chemical Society
Volume136
Pagination1398-1408
Date Published01
Type of ArticleArticle
ISBN Number0002-7863
Accession NumberWOS:000330598600049
Keywordsarrays, cds, gold, nanorod heterostructures, nanowire, oxidation reactions, photocatalytic hydrogen-production, photoinduced charge separation, tio2, visible-light, water
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.

DOI10.1021/ja409011y
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