An in situ SERS study of plasmonic nanochemistry based on bifunctional “hedgehog-like” arrays

An in situ SERS (surface-enhanced Raman scattering) study of plasmonic nanochemistry is realized on hierarchical Ag nanocone arrays (“hedgehog-like” arrays, denoted as HLAs) without any conventional catalyst. Ag nanocones are designed on 3D polystyrene (PS) microsphere arrays to provide a high density of hot spots within the laser-illumination area. Both experiments and numerical simulations demonstrate that the remarkable SERS and plasmonic catalytic performance of HLAs arise from the improved utilization rate of irradiation light in the third dimension and the tip enhancement effect of the nanocone arrays. On further combining their inherent SERS and catalytic properties, the in situ SERS study of plasmon-induced photocatalytic degradation reactions is realized. In this paper, not only the decomposition of methylene blue (MB) molecules is observed, but also the detailed molecular mechanisms of the reactions are revealed. Based on the bifunctional properties of the membrane–material interface, the HLAs are believed to be promising candidates in SERS and in situ SERS studies.