Effect of barium and potassium promoter on Co/CeO2 catalysts in ammonia synthesis

The presence of Ba or K promoter changes the properties of Co/CeO2 catalysts including the surface area, the crystallite size and the morphology of CeO2, the reduction degree of cobalt species and the adsorption performance of hydrogen and nitrogen. The samples promoted with an appropriate amount of Ba show higher ammonia synthesis rates, while the catalysts with high Ba loading or K promoter all exhibit low catalytic activities.154