A heat treatment method-induced product selectivity switch for CO₂ reduction over Ni/MoO₂

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Nickel (Ni) catalysts are widely used for CO2 conversion.
• Controlling the reaction pathway of CO2 utilization is crucial for efficient catalysis.
• Molybdenum dioxide (MoO2) has shown potential in catalytic applications.

Purpose of the Study:

• To investigate the effect of MoO2 encapsulation on Ni catalysts for CO2 reactions.
• To understand the mechanism of CO2 conversion over encapsulated and unencapsulated Ni catalysts.
• To explore the role of MoO2 and Ni in CO2 activation and hydrogen transfer.

Main Methods:

• Preparation of MoO2-encapsulated Ni and unencapsulated Ni catalysts using different heat-treatment methods.
• Characterization of the catalysts to confirm structure and composition.
• Evaluation of catalytic performance in CO2 conversion reactions.

Main Results:

• Successfully synthesized MoO2-encapsulated Ni and unencapsulated Ni catalysts.
• Unencapsulated Ni predominantly catalyzed CO2 methanation.
• MoO2-encapsulated Ni shifted the dominant reaction to the reverse water-gas shift (RWGS).
• MoO2 facilitated CO2 activation, while Ni supplied hydrogen via spillover effects.

Conclusions:

• MoO2 encapsulation effectively modifies the catalytic behavior of Ni.
• The MoO2/Ni interface plays a key role in directing the reaction pathway.
• Spillover effects are critical for the RWGS reaction over MoO2-encapsulated Ni catalysts.