High energy facet-dominated TiO2_X facet heterojunction with excellent carrier utilization for ultrasensitive SERS sensing and efficient degradation of antibiotic residues

Realizing efficient utilization of photogenerated carriers is crucial to boosting the photophysical and photo-chemical performances of semiconductors. Herein, (101) and (001) facets co-exposed anatase TiO2_X facet heterojunction with abundant oxygen vacancies was developed as a new surface-enhanced Raman scattering (SERS) substrate and also as an excellent photocatalyst for synchronous detection and degradation of antibiotic residues in actual water system. Due to the efficient carrier separation induced by facet heterojunction and the efficient charge migration derived from exposure of more high energy (001) facets, the TiO2_X facet hetero-junction exhibits an ultrahigh SERS enhancement factor of 1.07 x 107 for non-resonant Raman probe, with excellent spectral reproducibility and stability. More meaningfully, the developed substrate can realize an ultrasensitive detection for different kinds of antibiotic residues in real river water, even a comprehensive identification for multicomponent residues. Moreover, TiO2_X facet heterojunction can also execute an efficient photocatalytic degradation for residue pollutants in actual water system. And, the developed multi-function substrate possesses an excellent recyclability not only in SERS detection but also in photocatalysis.