Zhang Zhiyang, Kneipp Janina
Department of Chemistry and School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany.
BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, 12489 Berlin, Germany.
J Phys Chem Lett. 2021 Feb 11;12(5):1542-1547. doi: 10.1021/acs.jpclett.0c03732. Epub 2021 Feb 3.
The discussion of the surface-enhanced Raman scattering (SERS) spectra of -aminothiophenol (PATP) and of its photocatalytic reaction product 4,4'-dimercaptoazobenzene (DMAB) is important for understanding plasmon-supported spectroscopy and catalysis. Here, SERS spectra indicate that DMAB forms also in a nonphotocatalytic reaction on silver nanoparticles. Spectra measured at low pH, in the presence of the acids HCl, HSO, HNO, and HPO, show that DMAB is reduced to PATP when both protons and chloride ions are present. Moreover, the successful reduction of DMAB in the presence of other, halide and nonhalide, ligands suggests a central role of these species in the reduction. As discussed, the ligands increase the efficiency of hot-electron harvesting. The pH-associated reversibility of the SERS spectrum of PATP is established as an observation of the DMAB dimer at high pH and of PATP as a product of its hot-electron reduction at low pH, in the presence of the appropriate ligand.
对对氨基苯硫酚（PATP）及其光催化反应产物4,4'-二巯基偶氮苯（DMAB）的表面增强拉曼散射（SERS）光谱进行讨论，对于理解等离子体支持的光谱学和催化作用具有重要意义。在此，SERS光谱表明，DMAB也在银纳米颗粒上的非光催化反应中形成。在低pH值下，于HCl、H₂SO₄、HNO₃和H₃PO₄等酸存在的情况下所测得的光谱显示，当质子和氯离子都存在时，DMAB会被还原为PATP。此外，在存在其他卤化物和非卤化物配体的情况下成功将DMAB还原，表明这些物质在还原过程中起到核心作用。如前所述，配体会提高热电子捕获效率。在存在适当配体的情况下，PATP的SERS光谱与pH相关的可逆性表现为在高pH值下观察到DMAB二聚体，而在低pH值下观察到PATP作为其热电子还原产物。
