Photocatalytic oxidation of phenol was studied using nickel oxide (NiO) nanoparticles synthesized by sol-gel method. The morphology of synthesized catalyst was studied by using field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The average particle size was 6.5 nm as estimated by Scherrer formula and was confirmed by HRTEM and FESEM analysis. The photocatalytic activity of NiO was evaluated by degradation of phenol under irradiation of unique source like UV laser. The influence of various key parameters such as amount of photocatalyst, initial solution pH and the initial concentration of phenol was investigated. The operational parameters show the expected influence regarding the efficiency of the photocatalytic degradation process. The photocatalytic degradation efficiency of NiO was found to decrease with the increase in the initial solution pH. The degradation of the phenol followed a pseudo first-order rate kinetics with k = 5.7 x 10(-2) min(-1). (C) 2010 Elsevier B.V. All rights reserved.