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Title: Effects of Potassium Doping on CO Hydrogenation Over MoS2 Catalysts: A First-Principles Investigation

Periodic density functional theory calculations were performed to explore the effects of doping potassium (K) on the reactivity of CO hydrogenation to mixed higher alcohols over MoS2 catalysts. We found that the doped K species over the model MoS2(100) catalyst surface acts as a unique site for CO adsorption where either the K-C or the K-O bonding is allowed. The charge transfer from the K 4s electron to the conduction band of the MoS2(100) surface slightly enhances CO adsorption at the edge Mo sites. Due to the large electropositive nature, the presence of the surface K species, however, will hinder the dissociative adsorption of hydrogen. As a result, the doping K species drive CO hydrogenation selectivity toward the C2+ alcohols instead of hydrocarbons by increasing CO and decreasing hydrogen coverages on the MoS2 catalysts. To further elucidate the effect of doping K on the shifting of the selectivity toward CO hydrogenation, we calculated several key reaction steps leading to the H2CCO precursor formation, i.e., CO hydrogenation, the C-O bond scission and the C-C coupling (CH2+CO). The C-C coupling step is favorable for both the Mo and S edges. However, the undoped S edge has an overall more thermodynamically favorable reactionmore » profile up to C-O scission compared with the Mo edge. This work was funded by a CRADA project (No. PNNL/297) with Range Fuels. The research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The work involving the results analysis and mansucript writing was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.« less
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Publication Date:
OSTI Identifier:
Report Number(s):
42295; KC0301020
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Catalysis Communications, 52:92-97
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
Environmental Molecular Sciences Laboratory