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Cobalt oxide in spinel structure (Co 3 O 4) is an efficient catalyst for ethanol oxidation due to its potential as an oxygen source. To enhance the catalytic performance, Co 3 O 4 is dispersed on silica (SiO 2). The degree of dispersion and form of oxides on the support depend on the preparation method. The objective of this work is to compare physicochemical properties and catalytic performance in ethanol oxidation of silica-supported cobalt catalysts from different preparation methods. The catalysts were prepared by incipient wetness impregnation (IP), precipitation with reverse micelle (RM), and precipitation with NH 4 OH (PN) methods. The forms and dispersion of cobalt species were investigated by X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and X-ray photoelectron spectroscopy (XPS). The cobalt species from RM and IP methods were mainly Co 3 O 4 , but that from PN method was the mixed phases of Co 3 O 4 , CoO and Co 2 SiO 4. The RM method provided the best dispersion of Co 3 O 4 , surface Co3+ and lattice O2− on SiO 2. Consequently, the catalyst from RM method provided the highest ethanol conversion and CO 2 yield from all temperature ranges. Image 1 • Cobalt oxides supported on silica as catalysts were prepared by three methods. • Forms of cobalt were studied by X-ray absorption and photoelectron spectroscopies. • Reverse micelle and impregnation gave mainly Co 3 O 4 but not for precipitation by NH 4 OH. • The reverse micelle method provided the best dispersion of Co 3 O 4 on SiO 2. • The reverse micelle method had the highest ethanol conversion and CO 2 yield. [ABSTRACT FROM AUTHOR]