Ethylene diamine as a nitrogen source was applied to regulate carbon support.
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Nitrogen incorporation contributes to good dispersion of active phase.
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Nitrogen incorporation also leads to the formation of small-size carbides.
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Modified by N-atom and K boosts the selectivity of higher olefin-rich hydrocarbon.
Abstract
Preparation of highly efficient Fe-based catalysts is a reliable and achievable goal for catalyzing CO2 hydrogenation. Herein, ethylene diamine as a benign modifier well regulates the surface properties of carbon support, achieving a good dispersion of active small-size iron carbide sites. With the further incorporation of alkaline K promoter, heavy hydrocarbon selectivity (C5+) is increased from 14.8% to 39.8%. Combining several catalyst characterization (XRD, CO2-TPD, H2-TPR, TEM, and XPS) and reaction data, discloses that good dispersion, enhanced reduction/carburization behavior, and small-size carbides formation are essential for improving CO2 performance. Simultaneous doping of nitrogen atoms and alkali metal provides a promising means for CO2 fixation and rational design of functionalized metal-supported carbon catalysts.