A simple and efficient method for in situ preparation of highly stable polyimide (PI)-supported silver nanoparticles (AgNPs) was proposed. This process achieves excellent dispersion and high stability of AgNPs in the PI matrix. The formation of AgNPs in PI and the morphology evolution of PI/Ag nanocomposites were characterized by x-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and x-ray photoelectron spectra studies. The catalytic properties of these PI-supported AgNPs were investigated by monitoring the reduction of 4-nitrophenol by excess NaBH4 in water. The catalytic reaction was observed to have a pseudo first-order rate constant of 0.567 min−1 (9.45 × 10−3 s−1), which is comparable to other heterogeneous silver catalysts reported in the literature. Notably, the PI-supported AgNPs retained their relatively high catalytic activity over seven recycles with almost no leaching of catalytic species in the reaction solution. Moreover, the catalytic activity of the catalyst is still quite appreciable even after a six-month shelf-storage under room temperature.
