Potassium-Promoted Molybdenum Carbide as a Highly Active and Selective Catalyst for CO₂ Conversion to CO

Area of Science:

• Chemical Engineering
• Materials Science
• Catalysis

Background:

• Seawater contains a high concentration of dissolved carbon dioxide (CO2), representing a potential source for C1 feedstock.
• Direct hydrogenation of CO2 to liquid hydrocarbons is challenging, necessitating intermediate steps for efficient synthetic fuel production.
• The reverse water-gas shift (RWGS) reaction is a critical step for producing carbon monoxide (CO) from CO2.

Purpose of the Study:

• To identify a cost-effective, stable, and highly selective catalyst for the RWGS reaction.
• To enable the production of synthetic fuels from CO2 extracted from seawater.
• To facilitate the subsequent hydrogenation of CO to liquid hydrocarbons via Fischer-Tropsch synthesis.

Main Methods:

• Development and testing of a potassium-promoted molybdenum carbide catalyst supported on gamma-alumina (K-Mo2C/γ-Al2O3).
• Evaluation of catalyst performance for the RWGS reaction across a range of CO2 conversions.
• Characterization of the catalyst using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations.

Main Results:

• The K-Mo2C/γ-Al2O3 catalyst demonstrated low cost, high stability, and excellent selectivity for CO production via RWGS.
• The catalyst maintained high selectivity over a wide range of CO2 conversions.
• Characterization techniques confirmed the catalyst's structure, composition, and electronic properties, supporting its performance.

Conclusions:

• Potassium-promoted molybdenum carbide on gamma-alumina is a highly effective catalyst for the RWGS reaction, enabling CO production from CO2.
• This catalyst offers a viable pathway for utilizing seawater-derived CO2 as a feedstock for synthetic fuel production.
• The findings support the development of sustainable fuel technologies by leveraging abundant CO2 resources.