In this study that consists of three parts, three different heterogeneous catalysts were synthesized and after characterization by FTIR, XRD, XPS, TEM, FESEM, TG-DTA and ICP, their catalytic activity were investigated for reduction reaction of paranitrophenol, reduction of oxygen , adsorption and reduction of Cr (?). In the first part of this research, the graphene oxide was synthesized based of Hamers method, magnetic graphene oxide GO-MnFe2O4 was synthesized by immobilization of magnetic nanoparticle MnFe2O4 on the surface of graphene oxide. Magnetic graphene oxide was covalently modified with 3-aminopropyltrimethoxysilane. The imine functional group created by additio 3-methoxybenzaldehyde on the surface . Finally by adding Pd(AOc)2 nanohybrid of palladium was abbtianed. The catalytic characteristic of Pd(?)@GO-MnFe2O4 nanohybride in the reduction of para nitorphenol was investigated which the results shown in the Uv-Vis spectroscopy confirms the catalytic activity of this complex in reduction of para nitrophenol. In the second part of this research, the graphene oxide was synthesized based of Hamers method, magnetic graphene oxide GO-Fe3O4 was synthesized by immobilization of magnetic nanoparticle Fe3O4 on the surface of graphen oxide. Magnetic graphene oxide was covalently modified with benzoic hydrazide. Finally by adding Pd(AOc)2 nanohybrid of palladium was abbtianed. The synthesized materials were characterized with different methods and were studied with different electrochemical methods. The mechanistic aspects of the oxygen reduction reaction as well as the electrocatalytic effect of presence and absence of Pd(?)@GO-Fe3O4 in alkaline solution were studied by cyclic voltammetry, linear sweep voltammetry and chronoamperometry. The number of electrons transferred per O2 molecule (n) was obtained in the presence of Pd(?)@GO-Fe3O4 is close to 4 . The modified electrodes exhibit a high selectivity for ORR with a remarkable tolerance to crossover effects. More importantly, they have good durabilities. In the third part of this research, the graphene oxide was synthesized based of Hamers method. Then, the surface of the graphene oxide was doped with nitrogen by used of ammonium hydroxide. magnetic graphene oxide GO-MnFe2O4 was synthesized by immobilization of magnetic nanoparticle MnFe2O4 on the surface of graphen oxide. Finally by adding Pd(AOc)2, Pd@GO-NH2-MnFe2O4 nanocomposite nanohybrid was abbtianed In addition, surface of the nitrogen doped graphene oxide (NGO) is decorated MnFe2O4 nanoparticle. Finally, Pd@GO-NH2-MnFe2O4 nanocomposite was used for removal of Cr(VI) from aquase soloution. Then parameters including pH, contact time and concentration of salt were optimaized. Also, the sorption kinetics and isotherm of these sorbents were investigated.