Promotional effect of Au on γ-Al2O3 supported cobalt based catalyst for total oxidation of methane

Abstract

Effect of gold loading (within the range of 4 mass % - 16 mass %) on the behavior of the catalyst (Co/γ-Al2O3) for CH4 oxidation is studied. Gold promoted CoOx/γ-Al2O3 catalysts were prepared via deposition precipitation method and calcined at 550oC. A significant improvement in activity was observed (T100%=380 oC) toward CH4 oxidation with increase in gold loading, though a plateau was reached at ca. 13.45 wt. % Au content. The catalytic activity is studied on a fixed catalyst weight (500 mg) in an air flow containing 1 % of CH4 introduced to the reactor at a total feed rate of 150 mL/min. The catalyst characterization is done using XRD, TGA/DSC and SEM. The best catalysts according to the catalytic activity obtained are as follows: Au (13.45>10.44>16.27>07.21>04.06>0 wt. %)-CoOx/γ-Al2O3. It is found that the catalyst containing 13.45 wt. % of Au loaded on 18 wt. % Co/γ-Al2O3 is the most active catalyst as it decreases the temperature (T100%=380 oC) by 110oC required for methane oxidation in comparison to the catalyst that does not contain gold, i.e., 18wt.%Co/γ-Al2O3 (T100%=490 oC). © 2018 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.