Direct Conversion of Methane to Value-Added Hydrocarbons over Alumina-Supported Cobalt Modified by Alkaline Earth Catalysts

Methane can be directly converted to valuable hydrocarbons (C2+) via oxidative coupling of methane (OCM). The current work intensively investigated 20 weight percentage (20 wt%) of cobalt supported on alumina (20Co/Al2O3) modified with alkaline earth metals (Mg, Ca, Sr, and Ba), prepared using the wet impregnation method. The catalysts were tested in a fixed-bed reactor at atmospheric pressure. Notably, the 20Co/Al2O3 catalysts modified with Ca and Sr were highly active at low reactor temperatures (460-610 ?). The most active catalyst was 20Co/Al2O3 loaded with 2.5 wt% Sr, achieving the highest C2+ yield of 3.0%, with 10.6% C2+ selectivity and 27.8% methane conversion at 580 ?. In addition, the effects of various operating conditions were investigated: total feed flow rate, total catalyst weight, reactor temperature, and feed gas ratio. A time-on-stream test of the most outstanding catalyst revealed that its catalyst durability was excellent for 24 h of testing at 580 ?.{GRAPHIACAL ABSTRACT}

Automated summary

This study investigated the performance of 20 wt% cobalt supported on alumina catalysts modified with alkaline earth metals (Mg, Ca, Sr, and Ba) in the oxidative coupling of methane. The catalysts showed high activity at low reactor temperatures, with the 20Co/Al2O3 loaded with 2.5 wt% Sr achieving the highest C2+ yield of 3.0% at 580 ?. The effects of various operating conditions were also studied, and the most outstanding catalyst exhibited excellent durability for 24 hours of testing at 580 ?.