Hollow AuAgPt@Ag nanoframes with independent modular functional regions for in situ SERS monitoring of 4-NTP catalytic reactions.

Abstract

In situ and real-time monitoring based on surface-enhanced Raman scattering (SERS) can reveal the specific pathways and intermediate processes of catalytic reactions at the molecular level. The key to achieving effective in situ SERS monitoring lies in the preparation of bifunctional nanomaterials that possess both high SERS response and catalytic activity. However, most bifunctional nanomaterials currently used for in situ SERS monitoring are solid nanostructures, suffering from drawbacks such as ill-defined functional domains and low utilization of active sites. To address these issues, in this paper, symmetric AuAgPt@Ag nanoframes (s-AuAgPt@Ag) with hollow structure were prepared, successfully achieving spatial separation and functional synergy between the catalytic functional region (Pt-rich alloy framework) and the SERS-active region (pure Ag domains). Within this structure, the narrow gap formed between the two Ag ends constitutes a highly efficient SERS "hot spot", while the exposed central framework portion is situated precisely within this hot spot region. The as-constructed s-AuAgPt@Ag nanoframes were assembled into a uniform and stable SERS substrate, which not only enabled efficient catalytic degradation of the harmful nitroaromatic compound 4-NTP, but also allowed in situ and real-time monitoring of the catalytic conversion pathway of 4-NTP at the molecular level. This work not only demonstrates the great potential of s-AuAgPt@Ag nanoframes as a SERS-catalysis platform for in situ and real-time monitoring of chemical reaction pathways, but also offers promising application prospects in the fields of catalytic monitoring and degradation of 4-NTP as well as the synthesis of aromatic amines and aromatic azo compounds.

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