Plasmon-Mediated Oxidation Reaction on Au/p-Cu2O: The Origin of Hot Holes

Abstract

More sustainable solutions are needed to produce chemicals and fuels, mainly to face rising demands and mitigate climate change. Light, as a reagent, has emerged as a route to activate small molecules, e.g., H2O, CO2, N2, and make complex chemicals in a process called photocatalysis. Several photosystems have been proposed, with plasmonic technology emerging as one the most promising technologies due to its high optical absorption and hot-carrier formation. However, the lifetime of hot carriers is unsuitable for direct use; therefore, they are normally coupled with suitable charge-accepting materials, such as semiconductors. Herein, a system is reported consisting of Au supported in p-Cu2O. The combination of p-Cu2O intrinsic photoactivity with the plasmonic properties of Au extended the system’s optical absorption range, increasing photocatalytic efficiency. More importantly, the system enabled us to study the underlying processes responsible for hot-hole transfer to p-Cu2O. Based on photocatalytic studies, it was concluded that most of the holes involved in aniline photo-oxidation come from hot-carrier injections, not from the PIRET process.

Hot-Carrier Transfer across a Nanoparticle–Molecule Junction: The Importance of Orbital Hybridization and Level Alignment

“…The LSP, which is a collective electronic excitation, is excited by absorption of light and decays within tens of femtoseconds ,− ,− into a highly nonthermal (usually referred to as “hot”) distribution of electrons and holes. − Chemical reactions can then be catalyzed by hot carriers (HCs) transiently populating orbitals of nearby molecules, , which can lower reaction barriers . Two variants of this process can be distinguished.…”

Plasmonic Fabry-Pérot Nanocavities Produced via Solution Methods

“…The attachment of Au NPs to the CuSCN promoted by the 4-methoxythiophenol molecules is observed by the appearance of an absorption peak centred at 609 nm. The shift in the LSPR peak is explained by the change in the dielectric medium from water (εr ≈ 78 [26]) to CuSCN (εr ≈ 5.1 [27]), as seen with similar electrodes [28]. Note that without the Au metal film, the absorption across the visible range never exceeded 0.4.…”

Plasmon induced hot carrier distribution in Ag20‐CO composite

“…Another appealing attribute of LSPRs lies in their capacity to generate energetic hot electrons and hot holes, commonly termed plasmon-induced hot carriers (HCs). [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Recent research highlights that the distribution of HCs stemming from LSPR decay can markedly deviate from those generated by direct excitation. [38][39][40][41][42][43] In both scenarios, the initial electron-hole pair energy matches the photon energy; nevertheless, LSPR decay yields higher-energy electrons than direct excitation.…”

“…These LSPRs give rise to regions of highly enhanced electric fields, referred to as “hot spots”, [16,17] on the surface of PMNs. Another appealing attribute of LSPRs lies in their capacity to generate energetic hot electrons and hot holes, commonly termed plasmon‐induced hot carriers (HCs) [18–37] . Recent research highlights that the distribution of HCs stemming from LSPR decay can markedly deviate from those generated by direct excitation [38–43] .…”