Cs-Ba-Ru/La₂O₃-MgO Catalysts from Microdrop-Confined Pyrolysis for Superior NH₃ Synthesis under Mild Conditions

Area of Science:

• Heterogeneous catalysis
• Materials science
• Chemical engineering

Background:

• Ammonia synthesis is crucial for global food production.
• Ruthenium-based catalysts supported on magnesium oxide (MgO) are promising for ammonia synthesis.
• Support modification is key to enhancing catalyst performance.

Purpose of the Study:

• To investigate the effect of composite MgO-based supports (MOx-MgO) on the activity of Cs-Ba-Ru catalysts for ammonia synthesis.
• To identify optimal support compositions and catalyst parameters for improved ammonia synthesis performance.

Main Methods:

• Synthesis of 24 MOx-MgO composite supports using the microdrop-confined pyrolysis (MDCPy) method.
• Preparation of Cs-Ba-Ru/MOx-MgO catalysts via impregnation.
• Evaluation of catalyst activity under standardized ammonia synthesis conditions (400 °C, 3 MPa, H2/N2 ratio of 3:1).

Main Results:

• Lanthanum oxide-magnesium oxide (La2O3-MgO) composite supports significantly improved ammonia synthesis activity compared to pure MgO.
• Optimal Cs-Ba-Ru/La2O3-MgO catalysts achieved approximately 7 mol(NH3)/g(Ru)/h with 0.25-0.5 wt% Ru loading.
• The optimized catalyst demonstrated good stability during ammonia synthesis.

Conclusions:

• La2O3-MgO composite supports are highly effective for enhancing Ru-based ammonia synthesis catalysts.
• Optimized Ru loading and support composition are critical for achieving high activity and stability.
• The developed catalyst offers a promising route for efficient ammonia production under mild conditions.