Development of MoP catalysts for higher alcohol synthesis from syngas by exploiting support and promoter effects

Authors: 
Iris C. ten Have, Eduardo Valle, Alessandro Gallo, Jonathan L. Snider, Melis S. Duyar, Thomas F. Jaramillo
Year of publication: 
2019
Journal: 
Energy Technology

Molybdenum phosphide (MoP) catalysts have recently attracted attention due to their robust methanol synthesis activity from CO/CO2. In this study, synthesis strategies are employed to steer MoP selectivity towards higher alcohols, by investigating promotion effects of alkali (K), CO‐dissociating (Co, Ni) and non CO‐dissociating (Pd) metals. A systematic study with transmission electron microscopy (TEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and X‐ray Absorption Spectroscopy (XAS) revealed that critical parameters governing activity of MoP catalysts are P/Mo ratio and K loading, both facilitating MoP formation. Kinetic studies of mesoporous silica‐supported MoP catalysts show a two‐fold role of K, which also acts as electronic promoter by increasing the total alcohol selectivity and chain length. Palladium (Pd) increases CO conversion, but decreases alcohol chain length. The use of mesoporous carbon (MC) support had the most significant effect on catalyst performance and yielded a KMoP/MC catalyst that ranks among the state‐of‐the‐art in terms of selectivity to higher alcohols.

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