3D Ag/ZnO microsphere SERS substrate with ultra-sensitive, recyclable and self-cleaning performances: application for rapid in site monitoring catalytic dye degradation and insight into the mechanism

A highly sensitive, recyclable and self-cleaning surface-enhanced Raman scattering (SERS) substrate for rapid in situ monitoring photocatalytic degradation of dyes has been fabricated by growing Ag nanoparticles (NPs) on three-dimensional (3D) nanosheet-built ZnO microspheres (MSs). Used as a SERS substrate for the detection of Rhodamine 6 G (R6 G) molecules, the fabricated 3D Ag/ZnO MSs display high sensitivity and reproducibility as well as outstanding self-cleaning ability. The 3D Ag/ZnO MSs can detect the SERS signals of R6 G molecules even at very low concentration of 10(-9) M. In the light of these outstanding performances, the 3D Ag/ZnO MSs were employed as a SERS-active substrate for rapid in situ monitoring photocatalytic degradation of R6 G molecules. The experimental results distinctively demonstrate that the enhanced photocatalytic degradation of R6 G molecules is attributed to the efficient plasmon-induced charge transfer at the interface of the Ag NPs, ZnO MSs and R6 G molecules. The as-prepared 3D Ag/ZnO MSs display potential applications for as a multifunctional platform to rapid in situ monitoring photocatalytic degradation of organic pollutants in polluted water.