Dual application of a cyano-containing covalent organic framework: Photocatalytic degradation of dyes with fluorescence detection studies

In this work, a donor-acceptor type COF material named HDU-105 was synthesized and applied as a metal-free catalyst for the photocatalytic degradation of organic dyes. The photocatalytic experiments demonstrated that the degradation rate of RhB and MB reached 99.9% under various concentrations (5–20 ppm) and over a wide pH range (3–10), but consuming only 4 mg of HDU-105. Furthermore, the degradation rate for both organic dyes still maintained approximately 98% after four cycles. ESR spectra experiments revealed that ⋅O2- and ‧OH in HDU-105 may dominated the photocatalytic degradation as the main reactive substances. HDU-105 also exhibited an extremely low limit for MB detection with merely 5.7 ng L−1. All of this proves the high stability, remarkable reusability and fluorescence stability of HDU-105. To conclude, the cyano-containing COF material has potential for dyes removal application with an ultra-low MB detection limit.