Silica powder containing organized pores was prepared by a spray drying method. Silica and polystyrene latex (PSL) nanoparticles colloids were mixed and atomized to form micrometer-sized droplets. Nitrogen carrier gas was used to carry the resulting droplets into a vertical reactor that contained two heating zones: 200 °C and 450 °C, which were used, respectively, to evaporate the dispersing medium (water) and to decompose the PSL particles to give a porous silica powder. The pores on the surface of the powders were found to be arranged into a hexagonal packing, indicating that a self-organization process occurred spontaneously during evaporation of the solvent. The pore size was controlled by changing the size of the PSL particles. By adding an additional zone (third zone) maintained at high temperatures, the produced powders could be in-situ annealed. A comparison of the average volume of the powder before and after annealing (at 1500 °C) indicated that the porosity of the powder was about 70%. Togethe...