Temperature-tunable catalytic property of Pd–M (Ag, Cu) bimetallic nanoparticles stabilized by thermal-sensitive PDEAm-g-PAN/PSt polymeric microspheres

Thermal-sensitive poly( N , N -diethylacrylamide) grafted poly(acrylonitrile/styrene) (PDEAm- g -PAN/PSt) polymeric microspheres were prepared from PDEAm macromonomer, St and AN by dispersion copolymerization . The polymeric microspheres had raspberry-like morphology with large surface area. Palladium–metal (Pd–M) (M: copper, Cu, silver , Ag) bimetallic nanoparticles were stabilized on the surface of the PDEAm- g -PAN/PSt microspheres via the coordinate interaction between amide groups in PDEAm and metal ions with the reduction of the corresponding ions. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetry analysis (TGA) results confirmed the size and composition of the immobilized Pd–M nanoparticles. The Pd–M bimetallic nanoparticles showed superior catalytic efficiencies for the reduction of 4-nitrophenol (4-NP) than the monometallic nanoparticles. The catalytic activity of the Pd–M bimetallic catalysts could be controlled by the molar ratio of Pd and M ions and composition of Pd–M nanoparticles. Moreover, the catalytic property of the Pd–M nanoparticles could be regulated by temperature and increased with increasing the temperature above lower critical solution temperature (LCST). Furthermore, the Pd–M nanoparticles could be easily recycled and reused to catalyze 4-NP for five times without loss of activity. These bimetallic nanoparticles possess great potential in future practical application in catalytic technology.