In-situ synthesis of metal-organic framework embedded in ordered mesoporous silica functionalized with carboxyl groups for 4-nitrophenol to 4-aminophenol

Herein, the –COOH functionalized ordered mesoporous silica (OMS-C) was successfully synthesized using 3-phosphonopropionic acid as a functionalized reagent via one-pot co-condensation method. Then Cu 2+ ions were adsorbed by the –COOH groups present on the OMS surface. Finally, the composite material (MOF-199@OMS-C) functionalized by Metal-Organic Framework (MOF-199) was in-situ prepared through the Cu 2+ ions adsorbed by the OMS-C. The experimental results of N 2 adsorption–desorption, low-angle XRD, and TEM showed that MOF-199@OMS-C composites possessed an ordered 2D hexagonal mesoporous structure, high specific surface area and the formation of MOF-199 in the pore of OMS-C. Moreover, FT-IR, Raman, XPS, and TG analysis demonstrated the carboxylation on the surface of OMS, successful synthesis, and immobilization of MOF-199 within the pores of OMS-C through the –COOH of OMS, as well as the interaction between OMS-C and MOF-199. The MOF-199@OMS-C composites exhibited good catalytic activity in the reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The apparent kinetic constant of the reduction reaction of 4-NP was 0.26 min −1 under the optimum reaction condition. The MOF-199@OMS-C composites prevented the loss and structural damage of MOF-199, and its catalytic activity even remained stable after 4 cycles. In addition, the kinetic curves of reduction reaction of 4-NPs were consistent with first-order kinetics.