Preparation of porous chitosan/reduced graphene oxide microspheres supported Pd nanoparticles catalysts for Heck coupling reactions

Abstract Novel porous chitosan/reduced graphene oxide microspheres supported Pd nanoparticles catalysts (Pd@CS/RGO) were prepared by a combination of silica nanoparticles etching and freeze-drying treatments of CS/RGO/silica/PdCl2 composite microspheres. The microstructure of the Pd@CS/RGO microspheres catalysts have been investigated by X-ray photo electron spectroscopy (XPS), Raman spectroscopy, high resolution transmission electron microscopy (HR-TEM), thermo-gravimetric analysis (TGA), and X-ray diffraction (XRD), etc. The results revealed that: the novel catalysts showed open porous structure; CS had good miscibility with RGO nanosheets; Pd nanoparticles were well incorporated within CS/RGO matrix; the thermal stabilities of the catalysts were improved significantly over CS. Meanwhile, the Pd@CS/RGO catalysts have been demonstrated as highly active and easily recyclable catalysts for Heck reactions. The preparation process is simple, and the structure and performance of the catalytic material can be governed by changing the mass ratios of CS/RGO/silica/PdCl2 and the pore-forming process conditions.