Integration of plasmonic effect into spindle-shaped MIL-88A(Fe): Steering charge flow for enhanced visible-light photocatalytic degradation of ibuprofen

High electron-hole separation efficiency and wide spectrum absorption are desired for improving the photocatalytic activity. In this research, we integrate plasmonic Ag/AgCl with a typical semiconductor-like metalorganic framework MIL-88A(Fe) to form Ag/AgCl@MIL-88A(Fe) (ACMA) nanocomposites by a facile one-pot solvothermal method. The results demonstrate that ACMA nanocomposites not only broaden the visible-light absorption of MOFs, but also greatly accelerate photo-induced charge transfer rate. EDS mapping and HRTEM results suggest that Ag/AgCl is uniformly and densely dispersed on the surface of MOF, which is beneficial for charge flow and expedites the charge migration. By virtue of the structural and compositional features, these unique ACMA nanocomposites perform excellent photocatalytic activity on ibuprofen (IBP) in terms of high degradation efficiency, high mineralization and excellent cycling stability. ACMA-2 (Fe:Ag = 2:1) displays highly efficient photocatalytic activity on IBP under visible light irradiation, and the corresponding photo-degradation rate is 10.8 and 40.4 folds higher than that of MIL-88A(Fe) and Ag/AgCl, respectively. Total organic carbon (TOC) removal of IBP photodegradation reaches 91% by the catalysis of ACMA-2. Combined with the electrochemical tests, quencher experiments and analysis of related degradation products identified by ion chromatography (IC) and LC-MS-MS, oxidation by superoxide radicals (center dot O2-) as well as holes (h(+)) and electrons (e(-)) is the dominant degradation process in the photocatalytic degradation of IBP. This work provides a new perspective for the preparation of environment-stable and efficient MOF-based photocatalysts by steering charge flow.