Effect of Supports on the Properties of Co-Mo Nitride Catalysts for Ammonia Decomposition

Supported Co-Mo nitride catalysts have been synthesized by incipient-wetness impregnation method and temperature-programmed reaction in N-2-H-2 mixed gases. The effect of support types, namely carbon nanotubes(CNTs), active carbon(AC), 5A zeolite and Al2O3 on the properties of the prepared catalysts for ammonia decomposition has been investigated by XRD, H-2-TPR and SEM techniques. The results showed that CNTs was the optimum support for Co-Mo nitride catalyst. At 550 degrees C, NH3 conversions over CoMoNx/AC, CoMoNx/Al2O3 and CoMoNx/5A Zeolite catalysts were only 14.7%, 65.4% and 68.7%, respectively, while NH3 conversion over CoMoNx/CNTs catalyst was up to 84.4%. XRD and H-2-TPR results indicated that the active species consist of CoMoO4, MoO3, gamma-Mo2N and Co3Mo3N crystallites, which can be reduced at elevated temperatures at H-2 atmosphere. The SEM characterization demonstrated that Co-Mo nitrides particles disperse uniformly on the CNTs.