Metal single atoms have been demonstrated to induce surface-enhanced Raman scattering (SERS) due to their effectiveness in the modification of electronic structure. However, precisely modulating the relative positions of metal single atoms on sub-nanolattices remains a formidable challenge, which makes SERS studies of metal single atoms dependent on localized environments still lacking. Herein, we rely on polyethylene glycol (PEG) as a soft template to achieve the modulation of the relative positions of W atoms on titanate nanotubes (W-TNTs) and probe the local-environment-dependent SERS induced by metal single atoms based on this technique. We find that the relative position of the W single atoms greatly affects their SERS performance. This phenomenon has been attributed to the difference in charge transfer ability between single W atoms of different configurations, with isolated W atoms inducing a significantly higher density of electronic states near the Fermi energy than associated W atoms, leading to an enhanced polarization of the probe molecule and subsequently a stronger Raman signal. Our findings demonstrate a technique to effectively control the relative positions of single atoms and provide insights into single-atom-induced SERS associated with localized environments, which will facilitate the rational design of SERS substrates based on metal single atoms. Atomically dispersed metal atoms on semiconductor surfaces alter the local surface carrier distribution. Here, the authors demonstrate the improvement of the SERS activity of titanate nanotubes by controllable loading with monoatomic W species.
Zhou et al. (Thu,) studied this question.