Cabon dioxide hydrogenation over mesoporous titania supported-cobalt catalyst

Abstract

CO₂ hydrogenation of Co-catalysts on mesoporous titania (mixed and pure rutile phases), which was synthesized by oxidation and peptization process between TiC-precursor and aqueous nitric acid (5 M, 70 °C, 8 and 48 h), and effect of ruthenium (Ru) metal promoted on catalyst support were investigated. It was found that Co/Mixed phase and Co/R had higher specific surface area, pore volume, active site, %Co dispersion and active metal surface area than those of Co/P25 (commercial one), which showed lower conversion and reaction rate value. Due to high carbon residue (about 4.5 times higher than commercial one) on the supports from synthesis process and the formation of cobalt titanate, it resulted in a decrease in the degree of reduction without any significant change in the reduction behaviors. When the catalyst supports were promoted with ruthenium metal, it enhances dispersion and reduction efficiency of cobalt species. Moreover, with Ru-promoted catalyst, the calcined temperature is higher than that of the unpromoted one. Carbon residue was removed to the same level of commercial support, but specific surface area was decreased to this level, too. Conversion and rate of CO₂ hydrogenation took up to high value, but not significant compared to the Co-catalyst using the commercial support.