Co supported on Mg–La mixed oxides as an efficient catalyst for ammonia synthesis.

Ammonia presents a promising hydrogen source and energy carrier for mobile and stationary applications. The development of new and cheaper catalysts for ammonia synthesis is thus of great importance in improving the efficiency of the Haber-Bosch process. Here we report the investigation of ammonia synthesis on cobalt catalysts supported on magnesium–lanthanum mixed oxides with varying Mg/La molar ratios. Our studies revealed that the catalyst's activity is tuneable by varying the support composition, allowing an adjustment of the surface adsorption properties. Owing to the increased basicity of the support and weaker interactions between cobalt and hydrogen atoms, the catalyst supported on mixed MgO–La 2 O 3 oxide with Mg/La molar ratio of 7 demonstrated the highest activity and stability for ammonia synthesis as compared to other reported cobalt catalysts. [Display omitted] • Cobalt catalysts supported on MgO–La 2 O 3 mixed oxides for ammonia synthesis. • Dependence of the surface basicity on the performance of the cobalt catalysts. • Tuning the surface adsorption properties by varying the support composition. [ABSTRACT FROM AUTHOR]