Gold-Coated Flower-Like TiO2 Microparticles Wrapped with Reduced Graphene Oxide for SERS Monitoring and Photocatalytic Degradation of Organic Pollutants

The development of powerful technologies to simultaneously monitor and eliminate toxic organic pollutants is a vital focus of environmental research. For this purpose, a recyclable surface-enhanced Raman scattering (SERS) substrate was successfully prepared by successively depositing gold nano particles (AuNPs) and a reduced graphene oxide (rGO) film on TiO2 microflower particles by two-step in situ reduction processes. The prepared TiO2@Au-rGO ternary composites exhibit not only good SERS performance via molecule enrichment of rGO and surface plasmon resonance (SPR) capability, but also enhanced photocatalytic degradation activity because of the increased broadband UV-visible-light-harvesting efficiency and SPR-enhanced charge transfer. The detection limit of rhodamine 6G (R6G) as low as 10-11 M and excellent reproducibility were achieved. Additionally, the TiO2@Au-rGO ternary composites yield complete removal of R6G within 15 min under broadband UV-visible light illumination, wherein their apparent reaction-rate constant is 2.8 and 5.5 times larger than those of binary TiO2@Au and pure TiO2, respectively. Meanwhile, no distinct SERS and photocatalytic activity loss were observed even after five reusability tests, achieving the recycling SERS application by photocatalytic degradation. Most importantly, the as-fabricated ternary samples can be explored for the efficient capture, sensitive detection, and self-cleaning degradation of 2,2 & PRIME;,4,4 & PRIME;-tetrabromodiphenyl ether (BDE-47), revealing great potential applications in the SERS-based simultaneous monitoring and removal of trace aromatic persistent organic pollutants.