Dual-functional TiO2/Ag/NF SERS substrate with 3D channel structures for organic pollutant trace detection and degradation

Abstract

Surface-enhanced Raman scattering (SERS) substrates are essential to realizing the SERS effect. Meanwhile, these substrates often get contaminated after testing and cannot be reused. Herein, the nickel foam (NF) skeleton was modified with TiO2 and Ag to synthesize TiO2/Ag/NF three-dimensional (3D) SERS substrates via dip-assisted spin coating combined with a silver mirror reaction. The substrates exhibited the outstanding SERS activity with a limit of detection (LOD) of 10−8 M for rhodamine 6G (R6G) and crystal violet (CV), as well as the enhancement factor are 1.18 × 106 and 1.39 × 106, respectively. Besides that, the signal attenuation was only about 19 % after 30 days of exposure to the natural environment. Moreover, the adsorbed dyes (10−4 M) were successfully degraded under ultraviolet light irradiation for 180 min, and about 70 % of the signal was still retained after three degradation cycles, which demonstrated excellent self-cleaning performance. Additionally, the substrates also showed good sensitivity and degradation ability for CV in river water, at a LOD of 10−7 M. The degradation time of CV (10−4 M) was 210 min, and the high SERS activity was still retained after three cycles. Thus, the proposed 3D TiO2/Ag/NF dual-functional SERS substrates have great potential for rapid monitoring and degradation of organic pollutants in wastewater.