In new research published in Energy & Environmental Science, chemical engineers from the University of Rochester, the Naval Research Laboratory, the University of Pittsburgh, and OxEon Energy detail the most recent update in the mission to generate fuel from seawater.
The research elaborates on a particular step in the conversion process, during which carbon dioxide is converted into monoxide. The new findings highlight the use of a potassium-promoted molybdenum carbide catalyst to complete this step.
"This is the first demonstration that this type of molybdenum carbide catalyst can be used on an industrial scale," says Marc Porosoff, assistant professor of chemical engineering at Rochester.
The Navy has invested in this process ever since 2014 when it was first suggested by a Naval Research Laboratory team led by Heather Willauer. Converting seawater into fuel would eliminate the need for oil and would allow for continuous operation.
The potassium-modified molybdenum carbide catalyst solves several problems that this project has been facing. First, it uses low-cost components necessary to first convert carbon dioxide into carbon monoxide via the reverse water-gas shift (RWGS) reaction. Second, it does not show any signs of deactivation under reaction conditions, as previous catalysts have.
Porosoff adds that the potassium acts to decrease the energy barrier related to the RWGS reaction, while the gamma-alumina makes sure the molybdenum carbide catalyst particles stay separated, which maximizes the surface area of the chemical reaction.
All in all, write the authors of the study, “experiments across the molecular, laboratory and pilot scales demonstrate that K-Mo2C/γ-Al2O3 is an economically-viable RWGS catalyst with promising future applications in the US Naval Research Laboratory's seawater-to-fuel process, downstream methanol synthesis and FT.”