Highly Dispersed Molybdenum Carbide Clusters Enable Efficient CO₂ Hydrogenation.

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• The reverse water-gas shift (RWGS) reaction converts CO2 to CO, a key synthesis feedstock.
• High temperatures are needed for RWGS, posing challenges for catalyst activity and stability.
• Noble metal catalysts are active but expensive and prone to deactivation.

Purpose of the Study:

• To develop a highly efficient and stable noble-metal-free catalyst for the RWGS reaction.
• To investigate the catalytic performance of sub-nanometer molybdenum carbide (MoC) clusters supported on carbon.
• To understand the structure-activity relationship governing the RWGS catalysis on MoC.

Main Methods:

• Synthesis of sub-nanometer MoC clusters supported on carbon.
• Characterization using advanced techniques (e.g., spectroscopy, microscopy).
• Performance evaluation in RWGS reaction, including activity, selectivity, and stability tests.
• Density Functional Theory (DFT) calculations to elucidate reaction mechanisms.

Main Results:

• MoC spontaneously forms sub-nanometer clusters on the support, maximizing active sites.
• Achieved high CO formation rates (1.26 molCO molMo-1 s-1) and mass-specific activity (1028 µmolCO gcat-1 s-1).
• Demonstrated near 100% CO selectivity, exceptional stability, and efficient CO2 activation.

Conclusions:

• Sub-nanometer MoC clusters represent a highly active, selective, and stable noble-metal-free catalyst for RWGS.
• Optimized dispersion and unique electronic properties of MoC sites enhance catalytic performance.
• This offers a sustainable and atom-efficient strategy for CO2 valorization.