化学
催化作用
光化学
拉曼散射
亚硝酸盐
拉曼光谱
等离子体子
纳米技术
表面等离子共振
表面等离子体子
电子转移
组合化学
纳米颗粒
光电子学
有机化学
材料科学
物理
光学
硝酸盐
作者
Xiangjiang Liu,Longhua Tang,Reinhard Nießner,Ying Yang,Christoph Haisch
摘要
The stunning large enhancement factor (∼108) of the surface-enhanced Raman scattering (SERS) effect leads people to wonder about the underlying enhancement mechanisms of the effect. But, a strong evidence of the existence of one commonly accepted mechanism (chemical enhancement), the origin of the symbolic “b2” bands (ca. 1140,1390, 1432 cm–1) of p-aminothiophenol (PATP), was recently found to be a false explanation, which were actually arisen from the product of a surface plasmon-assisted coupling reaction of PATP, p,p′-dimercaptoazobenzene (DMAB). However, the debate is far from over, especially because the mechanism of the above reaction has not been fully understood yet. In this paper, we for the first time report a new surface plasmon-assisted catalytic conversion of PATP to DMAB that NO2– ions can trigger the formation of DMAB on gold nanoparticles (GNPs) suspension under light illumination. The mechanism of the conversion is also discussed. All relevant data suggest the nitrite-triggered conversion of PATP to DMAB on GNPs is a surface plasmon-assisted oxidation reaction, involving transfer of multiple electrons from PATP to NO2– (electron acceptors) and protons, leading to the formation of DMAB. The proposed mechanisms may also help to understand the unclear surface plasmon-assisted catalytic coupling of PATP on the SERS substrates. Furthermore, inspired by the high selectivity of the above nitrite-triggered catalysis reaction, a simple and fast nitrite screening method was also developed, exhibiting good sensitivity. Considering other advantages of the assay, such as rapidness, simplicity of the detection procedures, and requirement of no sample pretreatment, it is a promising method for on-site fast screening or point-of-care application.
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