Investigation of Enhanced Water Oxidation under Plasmon–Nanocavity Strong Coupling Using In Situ Electrochemical Surface-Enhanced Raman Spectroscopy

Abstract

Strong coupling between a localized surface plasmon resonance (LSPR) at the surface of metal nanoparticles (NPs) and a Fabry–Pérot (FP) nanocavity can facilitate photochemical reactions. It is very interesting and critical to study the enhancement mechanism of plasmon-induced chemical reactions under plasmon–nanocavity strong coupling to further improve the photochemical reaction efficiency. In this study, we fabricated a LSPR–FP nanocavity strong coupling photoelectrode composed of Au–Ag alloy NPs, titanium dioxide (TiO2), and a Au film as a working electrode to investigate the mechanism of water oxidation enhancement under plasmon–nanocavity strong coupling conditions. In situ electrochemical surface-enhanced Raman spectroscopy measurements were performed to detect the intermediate species of water oxidation under a series of electrochemical potentials. The Au–O and Au–OH stretching vibrations related to the intermediates of water oxidation were investigated. Compared with the Au–Ag alloy NPs/TiO2 structure without strong coupling, the surface-enhanced Raman spectroscopy signal of the Au–O stretching vibration on the strong coupling electrode exhibited a more negative onset potential, indicating that more efficient water oxidation occurred on it. This efficient water oxidation in the strong coupling photoelectrode was considered a result of the quantum coherence between the Au–Ag alloy NPs through the nanocavity.

Scheme to Enhance Hot Carrier Generation Owing to the Localized Mode of Hybridized Plasmon in Gold Nanoparticle Arrays

“…Given the recent rapid advancements in nanoscale fabrication technology, the precise control of hybridized plasmon modes has become increasingly feasible. This suggests that the formation of localized hybridized plasmon modes using precise techniques promotes chemical reactions such as water splitting and artificial photosynthesis . Consequently, they have garnered extensive attention in the field of photochemistry, leading to a substantial enhancement in the efficiency.…”

Hot Electrons in Catalysis

“…Kumar et al show that near-infrared (NIR) light excitation of NIR-resonant triangular Au nanoprisms induces the hydrolysis of dimethylphenylsilane but likely does so via a photothermal effect rather than photochemical enhancement. Zang et al show that photoelectrochemical water splitting can be enhanced by strong coupling of localized surface plasmon resonances (LSPRs) with a Fabry–Pérot nanocavity. Lee at al .…”

Recent Developments in Single-Entity Electrochemistry

“…With in situ spectroelectrochemical measurements, the authors found that the core–shell nanostructures were capable of enhancing SERS signals as single, isolated particles rather than aggregates, which then allowed localization of single particles on the substrate through reconstructed images. This advancement in localizing the SERS signals from single particles emphasizes the high sensitivity of SERS in detecting molecular changes in redox-active molecules and may eventually enable the identification of intermediates produced during electrochemical reactions of interest. − …”