A hybrid Ag/TiO2 nanoarray-based in situ charge transfer toward multi-functional active-platform

Abstract

Designing an efficient heteronanostructure array for surface-enhanced Raman scattering (SERS) to enable ultrasensitive and reproducible detection of analytes and degrading organic contaminants provides new perspectives for chemical and biological detection at trace levels and environmental remediation. Here, we design and fabricate a heterostructure consisting of Ag nanoparticles (NPs) in-situ grown on high-density arrays of vertical TiO2 nanorods (NRs) (denoted Ag/TiO2 NRs). As a result, compared with pristine TiO2 NRs, the as-obtained Ag/TiO2 NR substrate possesses a SERS activity for detecting rhodamine 6G (R6G) with a detection limit as low as 10−12 M and an enhancement factor up to 1.2 × 1010. In addition, the substrate exhibits the highest degradation rates of R6G of 82% under illumination with visible light and an excellent self-cleaning effect under UV-assisted light. Such remarkable enhanced efficacy of the binary Ag/TiO2 NRs nanocomposites may be attributed to the i) appropriate band alignment based on the synergistic effect of Ag decorated on TiO2 NRs; ii) a large adhesion area and the localized surface plasmon resonance (LSPR) of Ag; and iii) high-density and engineering hotspots in the active platform. These properties make the heterostructure Ag/TiO2 NR platform promising candidate for detecting analytes and photocatalytic applications.