Eur. Phys. J. Plus (2021) 136: 1173
https://doi.org/10.1140/epjp/s13360-021-02167-4

Regular Article

Photocatalytic activity of silver/silica core–shell nanoparticles for reversible azo-dimerization

The Beijing Key Laboratory for Nano-Photonics and Nano-Structure, Department of Physics, Capital Normal University, 100080, Beijing, China

^a lszhang@cnu.edu.cn

Received: 21 April 2021
Accepted: 10 November 2021
Published online: 23 November 2021

Abstract

Surface-enhanced Raman scattering (SERS) is a promising technique for the study of plasma-driven photocatalytic reactions. It can not only detect the chemical information of probe molecules but also provide a suitable catalytic substrate for surface catalytic reactions. In this paper, SiO₂-coated silver nanoparticles (Ag@SiO₂) were designed and synthesized, as the photocatalyst for the surface plasmon-enhanced chemical reactions. Driven by the localized surface plasmon resonance (LSPR) over the surface of Ag@SiO₂, 4,4′-dimercaptoazobenzene (DMAB) was successfully synthesized by the photocatalytic dimerization of 4-aminothiophenol (PATP) under the excitation of 532 nm laser. The reaction was found reversible under the same experimental conditions. In addition, we designed and synthesized a novel SERS substrate based on Ag@SiO₂. Meanwhile, the SERS substrate based on Ag nanofilms (AgNF) also was prepared for comparison. With the same condition excitation laser, Raman signal enhancement effects are different when applying AgNF and Ag@SiO₂, which could be attributed to the fact that the inert SiO₂ shell eliminates the CE mechanism of the Raman signal. These results provide a simple strategy to figure out the mechanism of the catalytic reaction based on SERS.