Liquid Bismuth Catalyst Enables High-CO-Selectivity in CO₂ Hydrogenation.

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• The reverse water-gas shift (RWGS) reaction is crucial for converting CO2 into valuable syngas.
• Achieving high CO selectivity in RWGS at moderate temperatures remains a significant challenge.
• Existing catalysts often suffer from low efficiency or poor selectivity.

Purpose of the Study:

• To develop a dynamic liquid-bismuth catalyst for improved CO selectivity in the RWGS reaction.
• To investigate the catalytic mechanism of liquid-bismuth on a vanadium oxide support.
• To enable efficient and selective CO2-to-syngas conversion at moderate temperatures.

Main Methods:

• In situ synthesis of molten bismuth nanodroplets confined on a defective vanadium oxide support.
• Utilizing a reversible Bi3+/Bi0 redox cycle for catalysis.
• Employing combined mechanistic studies and Density Functional Theory (DFT) calculations.
• Operating the RWGS reaction at 400°C.

Main Results:

• A dynamic liquid-bismuth catalyst was successfully synthesized and stabilized on a VOx support.
• The catalyst demonstrated high CO selectivity in the RWGS reaction at 400°C.
• Mechanistic studies revealed an H2-assisted redox pathway involving Ni-Bi dual sites.
• DFT calculations elucidated the roles of Bi and Ni sites in CO2 dissociation and CO desorption.

Conclusions:

• Dynamic liquid-bismuth catalysts offer a promising approach for selective CO2-to-syngas conversion.
• The Bi3+/Bi0 redox cycle and dual Ni-Bi sites are key to the catalyst's performance.
• This study highlights the potential of liquid-metal catalysis for sustainable chemical production.