A solid base, ZrO2-supported magnesia with high surface area (SA) has been prepared by impregnating hydrous zirconia with Mg(NO3)(2) solution and then calcining at 400 degrees C. MgO disperses on the surface of ZrO2 as a monolayer, which keeps ZrO2 in amorphous or tetragonal phase. TG-DTA results show that the decomposition temperature of Mg(NO3)(2) in monolayer phase is lower than that in crystalline phase and only monolayer-dispersed Mg(NO3)(2) turns into monolayer-dispersed MgO. The dispersion threshold of MgO on ZrO2 determined by XRD is 0.25 g MgO/g ZrO2, corresponding to a surface coverage near 1. The sample of MgQ/ZrO2 with the MgO content near the threshold possesses the highest SA (274 m(2)/g ZrO2), the largest number of basic sites and a larger share of sites with strong basicity. After supporting sulfonated cobalt phthalocyanine (CoPcS), the catalyst displays a very good initial activity of mercaptan oxidation for jet fuel (99% conversion of mercaptan to disulfide).