Continuous CO₂ capture and methanation over Ni-Ca/Al₂O₃ dual functional materials

Area of Science:

• Materials Science
• Chemical Engineering
• Catalysis

Background:

• Ni-Ca dual functional materials (DFMs) are studied for CO2 capture and reduction (CCR) to synthesize methane (CH4).
• Previous studies often used single reactors in oxygen-free environments, limiting real-world applicability.
• Continuous CCR operations, especially with oxygen, remain underexplored.

Purpose of the Study:

• To investigate continuous CCR for CH4 production using a double reactor system over Al2O3-supported Ni-Ca DFMs.
• To evaluate the performance of these DFMs in the presence of oxygen.
• To determine optimal material composition and reaction conditions for efficient CH4 synthesis.

Main Methods:

• Utilized a double reactor system for continuous CCR.
• Employed Al2O3-supported Ni-Ca DFMs with varying compositions.
• Characterized materials using X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectrometry (EDS), temperature-programmed desorption (TPD), and temperature-programmed surface reaction (TPSR).

Main Results:

• High calcium loading (Ni(10)-Ca(30)/Al2O3) was crucial for efficient CCR under isothermal conditions at 450 °C.
• The optimized DFM achieved 46% CO2 conversion, 45% CH4 yield, and 97% CH4 selectivity.
• Demonstrated good operational stability over 24 hours.

Conclusions:

• Continuous CCR for CH4 synthesis is feasible using Ni-Ca DFMs in a double reactor system, even with oxygen present.
• Optimized Ni-Ca DFMs exhibit excellent performance and stability for sustainable CH4 production.
• Material composition, particularly high Ca loading, significantly impacts CCR efficiency.