Preparation of Alumina-Supported Co-Mo Bimetallic Nitride Catalysts by Coprecipitation

The alumina-supported Co-Mo bimetallic oxide precursor was prepared by coprecipitation of ethanolic solution of Al(NO3)(3) and Co(NO3)(2), and aqueous solution of (NH4)(2)CO3 and (NH4)(6)Mo7O24. The Co-Mo bimetallic nitride catalyst Co-Mo-N/Al2O3 was synthesized by the NH3 temperature-programmed reaction based on the prepared oxide precursor. X-ray diffraction and N-2 physical adsorption were used to investigate the effect of calcination temperature on the phase and structural parameters of the catalyst. Temperature-programmed desorption, temperature-programmed surface reaction, and scanning electron microscopy were used to study the crystal stability, properties of active sites, and the surface morphology of the catalysts prepared by the coprecipitation method and impregnation method. The results indicated that the BET surface area of the samples was highly dependent upon the calcination temperature. The Co-Mo active components were dispersed more uniformly in the samples calcined at low temperature. The highest catalytic activity for ammonia decomposition was obtained from the sample calcined at 673 K. Compared with the sample prepared by impregnation, the Co-Mo-N/Al2O3 catalyst prepared by coprecipitation has higher activity, higher crystal stability, and more uniform dispersion of the active components.