Metal organic framework assisted Co-Ce mixed oxide catalyst for carbon monoxide and ethylene oxidation

A series of CeO₂/Co₃O₄ mixed nanocomposites with various Ce loading were fabricated by the pyrolysis of MOFs (metal organic frameworks), and their catalytic performance were evaluated by CO and C₂H₄ oxidation reaction. The prepared catalysts inherited polyhedral morphology of ZIF-67 (Zeolitic Imidazolate Framework-67) nanoparticles. By means of the synergistic effect of two different transition metal oxides, the catalysts exhibited superior performance for CO and C₂H₄ oxidation. The results show that for 2% - 8% doping ratio of CeO₂, the T₅₀ (50% conversion temperature) of CO and C₂H₄ decreased by 32 and 33 °C, respectively, as compared with the MOF-assisted pure Co₃O₄ catalyst. Stability of the catalyst was greatly enhanced with optimal Ce doping to Co₃O₄. A number of characterization techniques were used to study the morphology and physicochemical properties of the prepared catalysts. With the incorporation of Ce, polyhedral Co-Ce catalysts promoted specific surface area and lower reduction temperature. Likewise, Co³⁺/Co²⁺ and O_ads/O_latt improved with the addition of Ce, which played a significant role in CO and C₂H₄ oxidation at low temperatures.