Selective catalytic and kinetic studies on oxydehydrogenation of ethane with CO2 over lanthanide metal catalysts

Abstract

Single metal catalysts with different active components (La, Sm, Ce) and La loadings (5%, 10%, 15%) were prepared. Oxydehydrogenation of C2H6 with CO2 over the above catalysts was studied by catalyst activity experiments and characterization tests. The results indicate that the homogeneous reaction of CO2/C2H6 is the coupling of ethane pyrolysis and hydrogenolysis. Dehydrogenation has better selectivity than reforming on La/Sm/Ce-based catalysts; Sm exhibits the best catalytic activity due to carbon deposition resistance and many oxygen vacancies. C2H6 conversion on 10% Sm/SiO2 is 42.75% at 700 °C, but C2H4 selectivity is lowest. Because of the existence of $\mathrm{Ce}^{4+}$, Ce has the best C2H4 selectivity; it has potential to modify the catalyst, but its catalytic activity is lowest. La shows the best catalytic performance. The activation energy on 10% La/SiO2 is 83.99 kJ/mol, C2H4 selectivity is 96.84% at 700 °C, and its optimum loading is between 10% and 15%.

Keywords

• Ethylene
• Oxidative dehydrogenation
• Catalytic selectivity
• Lanthanide metal
• Apparent activation energy