In order to compare X-ray spectra of Hyd–Co–Si, two additional samples were prepared. Silica powders were mixed with Co3O4 with weight ratio 3%. Cobalt oxide was prepared by calcination cobalt nitrate in air as xerogels. The other one was prepared as the novel sol but with higher weight ratio, 10%, and calcined in air at a heating and cooling rate of 1 °C/min, and held for 3 h at 400 and 500 °C.