Nickel-based catalysts were prepared through the impregnation of various nickel ion concentrations on activated carbons (ACs). Then, their textural and surface chemistry properties were characterized using various analytical techniques. The performance of the different catalysts was evaluated during the degradation of 2-nitrophenol by ozone in aqueous solution. In particular, a kinetic study was performed to investigate the effect of ozone/supported catalyst coupling process on nitrophenol degradation. The main results indicate that the optimum catalytic activity was observed when 4% (wt/wt) of Ni was supported on AC reaching a catalytic ozonation efficiency of 95%. The results of the total organic carbon (TOC) indicate that the presence of either AC or Ni/AC catalyst considerably improves the degradation of the phenolic compound when compared with the single ozonation process. A combine use of O-3/AC-Ni reduces TOC up to 59% in 30 min. Therefore, the 4% Ni/AC is a promising catalyst for ozonizing organic pollutants in aqueous solution.