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

Abstract

The high concentration of CO₂ bound in seawater represents a significant opportunity to extract and use this CO₂ as a C₁ feedstock for synthetic fuels. Using an existing process, CO₂ and H₂ can be concurrently extracted from seawater and then catalytically reacted to produce synthetic fuel. Hydrogenating CO₂ directly into liquid hydrocarbons is exceptionally difficult, but by first identifying a catalyst for selective CO production through the reverse water-gas shift (RWGS) reaction, CO can then be hydrogenated to fuel through Fischer-Tropsch (FT) synthesis. Results of this study demonstrate that potassium-promoted molybdenum carbide supported on γ-Al₂ O₃ (K-Mo₂ C/γ-Al₂ O₃ ) is a low-cost, stable, and highly selective catalyst for RWGS over a wide range of conversions. These findings are supported by X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculations.

Keywords: CO2 conversion; heterogeneous catalysis; molybdenum carbide; potassium; reverse water-gas shift.