Multifunctional hollow porous Au/Pt nanoshells for simultaneous surface-enhanced Raman scattering and catalysis

Highlights: • Multifunctional hollow porous metal nanoshells (HP metal NSs) were synthesized by an electrostatic interaction and plasma treatment. • The HPAuNSs, HPPtNSs, and HPAu/PtNSs were compared for their SERS and catalytic functionalities. • The HPAu/PtNSs showed excellent multifunctionality: both high SERS and catalytic activity. Multifunctional nanostructures based on noble metal nanoparticles (NPs) have attracted great interest owing to their unique properties and potential for various applications. However, sophisticated control of the structural design through synthesis still remains challenging. Here we report a simple approach to synthesizing hollow porous metal nanoshells (HP metal NSs) comprising different metal NPs sintered together, with a structure and composition that can be readily controlled. The hybrid HP metal NSs can have multifunctionality in its single entity depending on their constituent metal NPs. As a demonstration, we prepared HP metal NSs comprising Au, Pt, and their hybrids, and measured their catalytic and surface-enhanced Raman scattering (SERS) activities in a model catalytic reduction of 4-nitrothiophenol to 4-aminothiophenol by sodium borohydride. The HP metal NSs comprising homogeneous Au or Pt NPs had high SERS activity and catalytic activity, respectively. In contrast, the HP Au/Pt hybrid NSs showed excellent multifunctional features with sensitive SERS performance and high catalytic activity owing to synergistic effects of the exposed Au and Pt NPs sites. Our simple strategy for fabricating HP metal NSs with a unique structure enables easy control of the NPs composition, and the resulting materials hold great promise for practical applications in various fields.