Interfacial self-assembled dual-functional nanocomposite films for SERS monitoring of visible-light photocatalytic degradation of organic dye pollutants

Photocatalytic degradation by visible-light responsive photocatalysts is an efficient strategy to treat organic dye pollutants and monitoring of the photocatalytic reaction mechanisms and kinetics is important to the design of high-performance photocatalysts. Herein, a dual-functional graphitic carbon nitride/gold nanoparticles (g-C3N4/AuNPs) nanocomposite film is introduced to monitor the photocatalytic reactions by surface-enhanced Raman scattering (SERS) while degrading organic dyes photocatalytically. The nanocomposite film fabricated by two-step interfacial self-assembly consists of orderly arranged g-C3N4 film anchored on a closely packed AuNPs monolayer film. The nanoplatform has excellent SERS characteristics such as a rhodamine 6G (R6G) detection limit of 8.8 × 10−10 M, and good SERS detection uniformity with a relative standard deviation (RSD) of 9.62%, which is crucial to quantitative determination and accurate monitoring of the photocatalytic reactions. The nanoplatform is employed in visible-light photocatalytic degradation of organic dyes including R6G, methylene blue, acid orange II, and acid orange 74. The reactions follow the pseudo-first-order kinetics as revealed by SERS and the photocatalytic degradation mechanism is postulated to be the promoted charge separation. The results reveal a high-performance dual-functional nanoplatform suitable for visible-light photocatalytic degradation of organic dye pollutants and SERS monitoring of the reactions.