Fabrication of highly uniform Ag nanoparticle-TiO2 nanosheets array hybrid as reusable SERS substrates

Well-ordered TiO2 nanosheets arrays (TiO2 NSAs) are fabricated on the surface of carbon paper (CP) by a hydrothermal method, and Ag nanoparticles (Ag NPs) are in situ deposited at the surface of TiO2 NSAs with an optimized deposition time. The prepared Ag NPs/TiO2 NSAs/CP hybrid are proved to be photocatalysis induced self-cleaning SERS substrates with excellent Raman enhancement activity, uniformity, reusability and renewability. The analytical enhancement factor is 2.52 × 108 for 4-mercaptobenzoic acid. Meanwhile, the substrate has excellent spot-to-spot uniformity and long-term stability. In addition, the Ag NPs/TiO2 NSAs/CP hybrid can renew and be reused for several times due to the photocatalysis induced self-cleaning feature. It can be used in analysis of chlorpyrifos with a low limit of detection. This reusable SERS substrate has great promising in applications of detecting toxic chemicals, environmental pollutants, food additives and so on.