Facet junction of CeO2 with high SERS activity for sensitive detection of ATP

Crystal facet engineering is proven to improve charge transfer of semiconductors. However, the facet-dependent properties and potential mechanisms of CeO2 for surface-enhanced Raman scattering (SERS) performance have not been explored. SERS effect is a surface sensitive technology, so it is very important to study the relationship between semiconductor surface topography and SERS activity. Here, we synthesized CeO2 (J2) with co-exposed {100} and {111} facet junction to effectively promote charge transfer (CT) between CeO2 (J2) substrate and methylene blue (MB), so that the SERS activity is significantly enhanced compared to CeO2 with only one exposed facets, which had a higher SERS activity with an enhancement factor (EF) of 3.77 × 106. The phenomenon is due to that the facet junction of CeO2 (J2) can promote electron-hole (e--h+) separation under light irradiation for more efficient CT. In addition, the oxygen vacancies enriched in CeO2 (J2) can provide an extra charge transfer path, which also facilitates the enhancement of SERS activity. Furthermore, the CeO2 (J2) with excellent SERS activity was used to detect ATP with a detection limit of 6.90 nM. This work provides a new SERS platform and opens up a perspective for preparation of SERS semiconductor substrates.