The high concentration of CO bound in seawater represents a significant opportunity to extract and use this CO as a C feedstock for synthetic fuels. Using an existing process, CO and H can be concurrently extracted from seawater and then catalytically reacted to produce synthetic fuel. Hydrogenating CO 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-Al O (K-Mo C/γ-Al O ) 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.