Investigation of the Plasmon-Activated C–C Coupling Reactions by Liquid-State SERS Measurement

Abstract

The implementation of plasmonic materials in heterogeneous catalysis was limited due to the lack of experimental access in managing the plasmonic hot carriers. Herein, we propose a liquid-state surface-enhanced Raman scattering (SERS) technique to manipulate and visualize heterogeneous photocatalysis with transparent plasmonic chips. The liquid-state measurement conquers the difficulties that arise from the plasmon-induced thermal effects, and thus the plasmon based strategies can be extended to investigate a wider range of catalytic reactions. We demonstrated the selection of reaction products by modulating the plasmonic hot carriers and explored the mechanisms in several typical C−C coupling reactions with 4bromothiophenol (4-BTP) as reactants. The real-time experimental results suggest brand new mechanisms of the formation of C−C bonds on plasmonic metal nanoparticles (NPs): the residue of 4-BTP, but not thiophenol (TP), is responsible for the C−C coupling. Furthermore, this technique was extended to study the evolution of the Suzuki−Miyaura reaction on nonplasmonic palladium metals by establishing the charge transfer channels between palladium and Au NPs. The cleavage and formation of chemical bonds in each individual reaction step were discerned, and the corresponding working mechanisms were clarified.

VSe2–xOx@Pd Sensor for Operando Self-Monitoring of Palladium-Catalyzed Reactions

“…It can be found that the peak at 1560 cm –1 (BTP) weakened as the reaction proceeded while the peaks at 1600 cm –1 (MBP) intensified. There is no peak of byproduct 4,4′-biphenyldithiol observed (details available in section IV of the Supporting Information, Figures S10–S17). − For comparison, the typical SERS spectra and contour plots employing the VSe 2– x O x @Pd sensor under 532 nm laser are displayed in Figure d,e. According to the PICT resonance theory, the charge transfer between the VSe 2– x O x @Pd and BTP would be efficiently promoted when the laser energy (E 633 = 1.96 eV) is closed to the energy gap between the Fermi level of the Pd cluster and the LUMO level of BTP (∼1.86 eV) (details available in section V of the Supporting Information, Figures S18 and S19).…”

Flexible plasmonic nanocavities: a universal platform for the identification of molecular orientations

“…S2 †). 48 The plasmonic modes of a single-layer plasmonic membrane were characterized using UV-vis spectra, as shown in Fig. 1d.…”

Probing Oxidation Mechanisms in Plasmonic Catalysis: Unraveling the Role of Reactive Oxygen Species

“…The asprepared nanoarray was coated with reactant molecules and subsequently inversely placed onto a self-designed cell for liquid SERS measurements, as illustrated in Figure 1b. 12,39 The nanoarrays exhibit unique dual functionalities, serving as SERS substrates and plasmonic photocatalysts simultaneously. In this study, we take the plasmon-induced oxidation of p-mercaptobenzoic acid (PMBA) as a case study.…”

“…The centimeter-scale plasmonic nanoarray (Figure a) was fabricated on quartz substrate using ultrathin anodic aluminum oxide (AAO) membranes as masks in e-beam evaporation (diagrams and detailed characterizations see Figures S1–S6). − The nanoparticles were immobilized on the substrate, offering distinguished sample stability against chemical and environmental stimulus and eliminating the influence from particle aggregation (Figure S7). The as-prepared nanoarray was coated with reactant molecules and subsequently inversely placed onto a self-designed cell for liquid SERS measurements, as illustrated in Figure b. , …”