In this thesis, various electrocatalysts, including of Ni nanoparticles and its alloys or mixed compounds with non-precious transition metals were prepared on the graphene support or graphene hybrids. After characterization, the products were employed as the hydrogen evolution reaction electrocatalysts in alkaline media. In order to characterize the obtained samples, several techniques were employed such as FTIR, XRD, FE-SEM, TEM, Raman and XPS analysis. Also, for the providing of graphene, chemical reduction of graphene oxide was done. In the first section, polyvinylpyrrolidone -modified graphene was synthesized as a hybrid with additional functional groups for Ni nanoparticles support. The results showed a long term durability for this sample in comparison to the Ni nanoparticles supported on the graphene and without the application of polyvinylpyrrolidone. In the next section, a facile chemical reduction procedure for the synthesis of nickel nanoparticles on a ceria–reduced graphene oxide hybrid was reported. To optimize the amount of ceria in the products, various physical and electrochemical techniques were applied. The results showed the influence of ceria incorporation in the matrix on the size of the prepared nickel nanoparticles. The prepared composites were used as electrocatalysts for the hydrogen evolution reaction in alkaline media. The results showed an excellent catalytic activity of Ni/ceria–rGO (1,1) with lowest onset overpotential and Tafel slope. Also, the effect of ceria incorporation into the Ni/ceria–rGO on the electrochemical activity and impedance spectroscopy response of the samples were discussed comprehensively. The next section was devoted to the preparation of Ni alloys with available 3d row transition metals (Co, Fe, Mn, Cr, Cu and Zn) on the graphene support. The results showed the higher hydrogen evolution activity of Ni- Co alloy (Ni: Co mol ratio= 3:1) compared to other investigated samples. Also, TEM and FE- SEM images showed a cauliflower-like structures for the prepared sample. In the last section, Ni and a number of 3d row transition metals oxides were grown on the graphene support. In this work, Ni and Cr 2 O 3 mixed nanoparticles/rGO, showed a higher electrochemical activity than other Ni and M x O y /rGO samples. In order to investigate the morphology and structure of Ni- Cr 2 O 3 /rGO, the obtained sample was further characterized via TEM and XPS analysis. The obtained results of this thesis introduce the investigated samples as the promising electrocatalysts which could be employed in the cathode side of water electrolyzer in alkaline media.
