Harnessing the full potential of graphene for optoelectronic and electrochemical devices requires turn ling and goal-directed control of its electronic properties. We report a computational study of the electron density of states and catalytic activity of graphene in the perpendicular magnetic field. We focus on the influence of uniaxial strain, covalently bonded moieties, charged ions at graphene surface, and positively charged impurities located between graphene layer and substrate, on the Landau levels (LL) observed on density of states and the resulting catalytic activity. For this study, the reduction of ferricyanide to ferrocyanide serves as a benchmark electrochemical reaction. Results show that LLs strongly affect the shape of the cathodic reaction rate curve. Armchair strain and covalently bonded moieties do not affect the intensity of LLs. On the other hand, zigzag strain, charged ions represented by Gaussian-like potential, and positively charged impurities represented by Coulomb-like potential, give rise to a gradual disappearance of the LLs. Positively charged Coulomb-like impurities cause a shift of the density of states towards higher energy which results in an extraordinary increase of the standard rate constant by one order of magnitude at the impurities concentration of 0.1%.