Modeling the adsorbate coverage distribution over a multi-faceted catalytic grain in the presence of an electric field: O/Fe from first principles

Journal Article · Wed Aug 15 00:00:00 EDT 2018 · Catalysis Today

DOI:https://doi.org/10.1016/j.cattod.2018.04.016· OSTI ID:1518597

Bray, Jacob E. ^[1]; Hensley, Alyssa ^[2]; Collinge, Gregory B. ^[1]; Che, Fanglin ^[2]; Wang, Yong ^[1]; Mcewen, Jean Sabin ^[1]

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1. WASHINGTON STATE UNIV
2. Washington State University

The impact of an external electric field on the concerted behavior of oxygen over a multi-faceted catalytic Fe grain is determined via the interpolation of ab initio models of oxygen adsorption on Fe(100), Fe(110), and Fe(111) in the presence of an external electric field. The application of both negative and positive electric fields weaken the adsorption strength for oxygen on all three surface facets, with Fe(110) experiencing the greatest effect. Kinetic models of a multi-faceted catalytic Fe grain show that the average oxygen coverage over the grain surface is reduced under the influence of both a negative and positive electric field, which are consistent with phase diagram results at comparable pressures. Furthermore, we show that there is a weak synergistic effect between a Pd promoter and a positive electric field on the oxygen adsorption energy, i.e. the Pd promoter and electric field combination weaken the oxygen adsorption energy to a greater degree than the simple addition of both components separately. Overall, the work shows that the application of an applied external electric field may be a useful tool in fine-tuning chemical properties of Fe-based catalysts in hydrodeoxygenation applications.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1518597
• Report Number(s): PNNL-SA-138082
• Journal Information: Catalysis Today, Vol. 312
• Country of Publication: United States
• Language: English