Graphene oxide was functionalized with chitosan for palladium immobilization (GO–Chit–Pd), which was used as an efficient catalyst for the reduction of aromatic nitro compounds using sodium borohydride in water. To achieve the best catalytic efficacy, various parameters such as temperature, solvent, mole ratio of hydrogen sources, and the amount of catalyst were optimized. The method has been applied to the reduction of a broad range of nitroarenes with different properties. The easy purification, convenient operation, environmental friendliness, and high product yields render this method viable for use. The nanocatalyst can be easily separated and efficiently recovered and reused for multiple cycles without appreciable loss in its catalytic activity.
In the present study, nickel nanoparticles (Ni-NPs) immobilized on graphene oxide-chitosan (GO-Chit-Ni) have been synthesized and characterized as a catalyst for reduction of nitroarenes in water. For this purpose, GO has been functionalized with chitosan (GO-Chit). Then, Ni-NPs were immobilized on the surface of GO-Chit using a simple method. The GO-Chi-Ni nanocomposites were characterized using Fourier Transforms Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-Ray Diffraction Measurements (XRD), and Atomic Adsorption Spectrometry (AAS). The GO-Chi-Ni nanoparticles demonstrated appropriate catalytic activity in reducing nitroarenes to aryl amines in the existence of sodium borohydride (NaBH4) aqueous solution as a hydrogen source at 80oC. This catalytic system applies environmentally benign water as a solvent that is cheap, easily accessible, non-toxic, non-volatile, non-flammable and thermally stable. This type of catalyst can be applied several times with no considerable change in its performance.