In this dissertation, the main purpose is efficient electrochemical CO 2 reduction to produce value added compounds using metal and graphene based electrocatalysts. Also it covers the synthesis of a graphene-based polymeric nanocomposite using in supercapacitor applications. In the first part, an electrochemical system, based on copper nanofoam accompanied by 1-butyl-3-methyl-imidazolium bromide (BMIMB) as the homogeneous co-catalyst for the electrochemical conversion of CO 2 at ambient pressure and temperature was developed. Although, there have been some efforts for utilization of copper nanofoam or imidazolium-based catalysts toward the electro-reduction of CO 2 , evaluation of both catalysts to take advantage of the potential synergic effect of their combination would be an interesting aspect. The electroreduction of CO 2 in a CO 2 saturated electrolyte was optimized based on the highest CO 2 conversion efficiency in various conditions. The results show that the copper nanoporous foam, with the contribution of BMIMB would effectively reduce CO 2 and demonstrate a high CO 2 faradaic efficiency i.e. more than 46% improvement, compared to similar previously reported experiment. The results confirm the applicability of this experiment as a developed method for efficient CO 2 reduction. In the second part, an electrocatalyst consisting of platinum nanoparticles on histamine-reduced graphene oxide plates (Pt@His-rGO) supported by a glassy carbon substrate for the conversion of CO 2 to methanol has been developed. The nanocomposite was optimized in applied pH, potential, CO 2 purging time and platinum loading, for the highest current densities and faradaic efficiencies toward methanol production. The faradaic efficiency of 37% was obtained for methanol production. The remarkable activity toward alcohol production due to the application of a low potential to limit gaseous products and high CO 2 intermediates stabilization of presented electrocatalyst may make this nanocomposite a promising mean for fuel production to address environment and climate change challenges. In the third part, a modified carbonaceous nanocomposite was prepared using Nile blue functionalized reduced graphene oxide (rGO) decorated by copper nanoparticles (Cu@NB-rGO). This unique graphene oxide (GO)-based electrocatalyst was cast on a copper plate electrode and employed for efficient conversion of CO 2 to valuable products via electrochemical reduction in term of energy saving. The application of the represented electro-catalyst increased the electroactivity of the substrate toward the production of multi-carbon species with higher selectivity. The Cu@NB-rGO nanocomposite was optimized for rGO, Nile blue, and Cu nanoparticle- compositions as well as the applied potential for the highest CO 2 electro-reduction faradaic efficiency. The modified electrocatalyst was able to reduce CO 2 to value-added products (ethanol, acetic acid, formic acid, CO, and methane) with a total faradaic efficiency of about 86%. The evaluation of gas and liquid products was carried out by gas analyzer- gas chromatography, chemical oxygen demand (COD), and gas chromatography-mass spectrometry (GC-MS) techniques. The best results were observed at the potential of -1.0 V versus Ag/AgCl, rGO amount of 0.5 mg mL -1 , Nile blue and a copper concentration of 15 and 10 mM, respectively. In the last part, a quite simple method has been represented for the fabrication of polymeric crosslinked graphene nanocomposite and examined for supercapacitance properties. Since most of the azo dyes display the conjugated structures, their contribution to enhance the conductivity and capacitance of carbon containing compounds such as graphene could be an interesting area. Therefore, in the present work, chrysoidine (CHRYS) was polymerized in the presence of graphene oxide (GO) in which the produced polychrysoidine (PCHRYS) acted as a cross linker for GO nanosheets. The optimized components ratio of GO:PCHRYS forms the efficient porous graphene oxide-polychrysoidine (GO-PCHRYS) nanocomposite which easily stores charge and represents a rather high specific capacitance of 1129.73 F g -1 at the current density of 0.5 A g -1 . The electrode stability was determined after 10000 cycles via comparing initial and final capacitance and the results indicated that 89.8% of the initial capacitance had been maintained