Modulating the Plasmon-Mediated Oxidation of p-Aminothiophenol with Asymmetrically Grafted Thiol Molecules

Abstract

A surface plasmon can drive many photochemical reactions, in which effective charge separation and migration is a key. In analogy to the plasmon–semiconductor interface, the plasmon–molecule interface may also be used to improve the separation and migration of hot carriers. In this work, by using in situ Raman spectroscopy, molecular grafting on silver nanostructures is found essential for modulating the charge separation and p-aminothiophenol (PATP) oxidation reaction. When the LUMO of the grafted molecules match well the energy distribution of the plasmon-generated hot electrons, the PATP oxidation process accelerates significantly. Moreover, compared with symmetrical grafting, asymmetrical grafting is more effective in regulating the charge separation and plasmon-mediated chemical reaction. This work provides an effective strategy for deep understanding and fine modulation of plasmon-mediated photochemistry.

Molecular Coadsorption of p-Hydroxythiophenol on Silver Nanoparticles Boosts the Plasmon-Mediated Decarboxylation Reaction

“…In both cases, increasing the laser power will lead to an acceleration of the decarboxylation reaction, which is attributed to plasmon mediation of this decarboxylation reaction. A similar phenomenon has been observed in many reports. , …”

“…When the EF increased from 1.5 × 10 5 , and 8.8 × 10 5 to 1.7 × 10 6 , the reaction rate constant of the decarboxylation reaction increased from 0.071 and 0.69 to 0.76. The high dependency of the reaction rate constant on EF further suggests that the decarboxylation on AgNPs is a plasmon-mediated reaction, which is consistent with the reported work . Moreover, the increase in the reaction rate constant became less significant at a higher EF of 1.7 × 10 6 , indicating that the plasmon-mediated decarboxylation is not linearly correlated to the fourth power of the localized electric field.…”

“…Therefore, it may become possible to promote the separation of hot carriers at plasmon–molecule interfaces and thus plasmon-mediated chemical reactions. It has been reported that the charge transfer can be modulated at plasmon–molecule interfaces in surface-enhanced Raman scattering (SERS), controlled growth of gold nanocrystals, and photoelectrochemical hydrogen evolution. , Thus, surface adsorption of small molecules may become a highly effective approach to boost the plasmon-mediated chemical reactions. More importantly, the energy-level structure of the adsorbed molecules can be modulated easily by selecting suitable molecules or by substituting the functional group, providing a convenient and cost-effective way to match with the energy structure of the plasmonic metal.…”

Molecular Cocatalyst-Induced Enhancement of the Plasmon-Mediated Coupling of p-Nitrothiophenols at the Silver Nanoparticle–Graphene Oxide Interface

“…Surface adsorption of certain molecules may be another effective strategy to accelerate the plasmon-mediated reactions. Recently, thiophenol and phenyl molecules have been chemically adsorbed on the surface of plasmonic metals for highly efficient chemical reactions. − However, the molecules need to be strongly adsorbed on the surface of the plasmonic metal and may block the catalytically active sites, limiting the potential of surface molecular engineering in accelerating chemical reactions. To further improve the adsorption-induced enhancement of reactions, the molecules may also be adsorbed asymmetrically on the heterostructures of the plasmonic metal with other materials.…”

Monitoring the Thiol/Thiophenol Molecule‐Modulated Plasmon‐Mediated Silver Oxidation with Dark‐Field Optical Microscopy

“…By using plasmon-enhanced Raman spectroscopy, [16][17][18] our group has reported thiophenol molecule-induced acceleration of plasmon-mediated chemical reactions. [19,20] However, the contribution of the thiophenol molecules is not clear and the modulation of these reactions with molecular grafting needs to be further investigated. Moreover, the potential of the molecules in modulating other plasmon-mediated chemical reactions also needs to be investigated.…”