TNAs/g-C3N4/AuNPs heterojunction used as integrated device of photocatalytic degradation and SERS detection

Novel TiO 2 nanotube arrays (TNAs) involved heterojunctions are widely used as photocatalyst for pollutants, while the residues are usually detected by other method. A device which integrates photocatalytic degradation and enhancing detection signals could increase the atom utilization and decrease detection cost. In this work, a novel TNAs/g-C 3 N 4 /AuNPs heterojunction was prepared and used as photocatalyst and SERS substrate simultaneously. Dye of crystal violet was successfully degraded, and the concentration of residue was detected by Raman spectroscopy. There was a good linear correlation between the Raman intensity and the concentration of crystal violet from 10 −10 M to 10 −6 M, and the limit of detection (LoD) was 8.79 × 10 −11 M. Moreover, the prepared heterojunctions were used on wastewater and biological staining detection. In the applications of photocatalytic degradation and detection, the time-dependent SERS intensities demonstrated the photocatalytic degradation achieved more than 95% in 20 min, and almost completed in 25 min, and the heterojunctions showed good recyclability in at least 10 cycles. For SERS property, the original enhancement factor (EF) was calculated to be 7.43 × 10 6 , then the EF descended slightly and remained with less than 90% attenuation after 10 cycles.