In this presentation, we will report our recent first-principle calculations on cobalt-based catalysts for syngas conversion. (1) Pt-modulated cobalt catalysts for low-T FTS. Coupling with atomic-resolution scanning transmission electron microscopy, we proved that the formation of Co overlayer structures on Pt could enhance substantially the FTS activity, due to the improved energetics and kinetics imposed by the lattice mismatch between Co and Pt. (2) Crystallographic dependence of CO activation on cobalt catalysts: Hexagonal closed pack versus face center-cubic. We find that CO activation on HCP Co not only has much higher intrinsic activity than that of FCC Co but also prefers a different reaction route, i.e., direct dissociation with HCP Co but H-assisted dissociation on the FCC Co. The origin is identified from the formation of various denser yet favorable active sites on HCP Co not available for FCC Co, due to their distinct crystallographic structure and morphology. The great dependence of the activity on the crystallographic structure and morphology of the catalysts revealed here may open a new avenue for better, stable catalysts with maximum mass-specific reactivity. (3) Co@Co2C Catalysts. We find that cobalt carbide is noble-metal-like, and can provide the active sites for CO non-dissociative adsorption. The dual sites at the Co@Co2C interfaces could be used for synthesizing various oxygenates in syngas applications and hydroformylation without using precious transition metal catalysts.

First-principles study of Co-based catalysts for syngas conversion

249th National Meeting (2015)

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