A highly donor-doped (110) layered perovskite, La2Ti2O7, was found to be an efficient photocatalyst comparable to TiO2 P25 and better than K2La2Ti3O10, the latter being an undoped (100) layered perovskite, in oxidative degradation of CH3Cl in the gas phase under UV irradiation. The activity depended on the crystallinity and the surface area of perovskite oxide. The grinding methods of the mixed oxide precursors before sintering as well as the sintering temperature affected the crystallinity and the surface area of the formed perovskite. Loading of Ni to perovskite materials increased the photocatalytic activity in degradation of CH3Cl markedly by constructing a p-n junction between nickel oxide and perovskite material. The optimum nickel loading was dependent strongly on the sintering temperature and the surface area of the perovskite material, and a slight deviation from the optimal nickel loading caused a drastic decrease in the photocatalytic activity.