Catalytic Impedance Spectroscopy: Concept and Application on CO₂ Methanation

Area of Science:

• Surface chemistry and catalysis
• Spectroscopic techniques
• Chemical reaction engineering

Background:

• Understanding catalytic reaction mechanisms is crucial for optimizing industrial processes.
• Existing methods for studying reaction dynamics can be limited in scope or resolution.
• Complex catalytic systems require advanced analytical approaches to elucidate their behavior.

Purpose of the Study:

• To introduce and validate Catalytic Impedance Spectroscopy (CIS) as a novel method for studying catalytic systems.
• To demonstrate the experimental feasibility and application of CIS.
• To investigate the reaction mechanism of CO2 methanation over Ni catalysts.

Main Methods:

• Development of a complex modeling approach combining periodic excitation with time-resolved product detection.
• Implementation of a general experimental setup for CIS.
• Application of CIS to the catalytic CO2 methanation reaction on Ni catalysts.

Main Results:

• Successful demonstration of CIS feasibility in a real catalytic reaction.
• Experimental confirmation of the theoretically predicted rate-determining step (HCO* → CH*) in CO2 methanation on Ni.
• Characterization of the complex response function of the catalytic system.

Conclusions:

• CIS is a powerful technique for unraveling complex catalytic reaction mechanisms.
• The study provides valuable insights into the CO2 methanation pathway on Ni.
• Further development of CIS holds significant promise for catalysis research.