Plasmonic Photoelectrochemical Coupling Reactions of para-Aminobenzoic Acid on Nanostructured Gold Electrodes

Abstract

Surface plasmon resonance (SPR) bridges photonics and photoelectrochemistry by providing an effective interaction between absorption and confinement of light to surface electrons of plasmonic metal nanostructures (PMNs). SPR enhances the Raman intensity enormously in surface-enhanced Raman spectroscopy (SERS) and leads to the plasmon-mediated chemical reaction on the surface of nanostructured metal electrodes. To observe variations in chemical reactivity and selectivity, we studied the SPR photoelectrochemical reactions of para-aminobenzoic acid (PABA) on nanostructured gold electrodes. The head-to-tail coupling product “4-[(4-imino-2,5-cyclohexadien-1-ylidene)­amino]­benzoic acid (ICBA)” and the head-to-head coupling product p,p′–azodibenzoate (ADBA) were obtained from PABA adsorbed on PMN-modified gold electrodes. In particular, under acidic and neutral conditions, ICBA was obtained as the main product, and ADBA was obtained as the minor product. At the same time, under basic conditions, ADBA was obtained as the major product, and ICBA was obtained as the minor product. We have also provided sufficient evidence for the oxidation of the tail-to-tail coupling reaction product that occurred in a nonaqueous medium rather than in an aqueous medium. The above finding was validated by the cyclic voltammetry, SERS, and theoretical calculation results of possible reaction intermediates, namely, 4-aminophenlylenediamine, 4-hydroxyphenlylenediamine, and benzidine. The theoretical adsorption model and experimental results indicated that PABA has been adsorbed as para-aminobenzoate on the gold cluster in a bidentate configuration. This work offers a new view toward the modulation of selective surface catalytic coupling reactions on PMN, which benefits the hot carrier transfer efficiency at photoelectrochemical interfaces.

Plasmon-Enhanced C–C Bond Cleavage toward Efficient Ethanol Electrooxidation

“…22−25 In contrast, the plasmon effects on regulating electrocatalytic pathways as well as the underlying mechanism have been least investigated. 26,27 In this work, the Au@Pt nanoparticles with the plasmonic core and active shell are designed initially to boost concurrently the EOR activity and C1 selectivity in alkaline media under the visible light illumination at room temperature, during which local heating and energetic carriers make a mixed contribution with the local heating effect being dominant. In situ attenuated total reflection−surface enhanced infrared absorption spectroscopy (ATR-SEIRAS), 28−32 as a nondestructive surface sensitive analytical tool, is used to track the real-time evolution of surface species at different applied potentials with or without illumination.…”

“…Notably, if the LSPR occurs in the visible region, solar energy can be effectively utilized. So far, the relevant reports were mostly focused on the synthesis of various plasmonic nanostructures with a primary target to increase the catalytic activity. − In contrast, the plasmon effects on regulating electrocatalytic pathways as well as the underlying mechanism have been least investigated. , …”

Quantifying Hot Electron Energy Contributions in Plasmonic Photocatalysis Using Electrochemical Surface-Enhanced Raman Spectroscopy

“…29 Recently, Wu et al reported the difference between electro-oxidation and LSPR-assisted electro-oxidation in surface-enhanced Raman spectroscopic (SERS) measurements. 30 Here in this work, electrode potentials are introduced as a visualization tool to adjust surface potentials (Scheme 1a) for quantifying the energy of hot electrons. Several hot electron-sensitive chemicals including 4-nitrothiophenol (4-NTP) and 4-iodothiophenol (4-ITP) were coated on 60 nm Au NPs as SERS probes that can reflect the hot electron energy.…”

“…Gargiulo and co-workers quantified the energy of hot holes using EC–dark field scatter measurements . Recently, Wu et al reported the difference between electro-oxidation and LSPR-assisted electro-oxidation in surface-enhanced Raman spectroscopic (SERS) measurements . Here in this work, electrode potentials are introduced as a visualization tool to adjust surface potentials (Scheme a) for quantifying the energy of hot electrons.…”

Probing the Intermediates of Catalyzed Dehydration Reactions of Primary Amide to Nitrile in Plasmonic Junctions

“…Supported small GNPs are chemically reactive and have been used as effective heterogeneous catalysts in several chemical reactions under mild conditions . By shining visible light on the GNPs, the light energy can be harvested on the GNP surface through the localized surface plasmon resonance, which further decays through the non-radiative pathways into heat and high-energy hot electrons and holes to catalyze chemical reactions on the GNP surface. , The concentrated light field in the junctions can also greatly amplify signals of surface enhanced Raman spectroscopy (SERS), which has been used to monitor the organic reactions in situ and in real time up to the single-molecule level . To study the mechanism of chemical reactions, it is important to probe the intermediates.…”