Design of Carbon-Encapsulated Fe3O4Nanocatalyst with Enhanced Performance for Fischer-Tropsch Synthesis

Direct Construction of K-Fe3C@C Nanohybrids Utilizing Waste Biomass of Pomelo Peel as High-Performance Fischer–Tropsch Catalysts

As the only renewable organic carbon source, abundant biomass has long been established and developed to mass-produce functionalized carbon materials. Herein, an extremely facile and green strategy was executed for the first time to in situ construct K-Fe3C@C nanohybrids directly by one-pot carbonizing the pomelo peel impregnated with Fe(NO3)3 solutions. The pyrolytically self-assembled nanohybrids were successfully applied in Fischer–Tropsch synthesis (FTS) and demonstrated high catalytic performance. Accordingly, the optimized K-Fe3C@C catalysts revealed excellent FTS activity (92.6% CO conversion) with highlighted C5+ hydrocarbon selectivity of 61.3% and light olefin (C2-4=) selectivity of 26.0% (olefin/paraffin (O/P) ratio of 6.2). Characterization results further manifest that the high performance was correlated with the in situ formation of the core-shell nanostructure consisting of Fe3C nanoparticles enwrapped by graphitized carbon shells and the intrinsic potassium promoter originated in pomelo peel during high-temperature carbonization. This work provided a facile approach for the low-cost mass-fabrication of high-performance FTS catalysts directly utilizing waste biomass without any chemical pre-treatment or purification.

Selective synthesis of core-shell structured catalyst χ-Fe5C2 surrounded by nanosized Fe3O4 for conversion of syngas to liquid fuels

Enhancing liquid hydrocarbons selectivity and simultaneously suppressing CO2 formation are highly desirable yet challenges in iron-based Fischer-Tropsch synthesis. Herein, we report an in-situ oxidation method for the fabrication of a...

Conversion of furfuryl alcohol to ethyl levulinate in the presence of mesoporous aluminosilicate catalyst

The one-pot acid-catalyzed the conversion of furfuryl alcohol (FA) to ethyl levulinate (EL) was investigated in the presence of mesoporous aluminosilicate (TUD-1) with a high surface area (up to 579 m2 g−1) and well-interconnected mesospheres synthesized via a solvothermal process and characterized using scanning electron microscope, transmission electron microscope, X-ray diffraction, 27Al-NMR, and N2 sorption isotherm. The resulting solid acid catalyst was tested for the alcoholysis of FA with ethanol, affording 87.8% EL yield under the optimal reaction conditions of 120°C and 4 h. Moreover, the catalyst showed a good reusability with less loss of activity after a simple solvent washing and calcination procedure.

An Na-modified Fe@C core-shell catalyst for the enhanced production of gasoline-range hydrocarbons via Fischer-Tropsch synthesis

Although numerous studies have been conducted in the field of converting syngas to value-added fuels, selectively converting syngas to gasoline-range hydrocarbons (C_5–12 hydrocarbons) remains a big challenge. Alkali metal (namely, K, Na and Li)-modified Fe@C core–shell catalysts were synthesized by a one-step hydrothermal method for Fischer–Tropsch synthesis. An optimized selectivity of 56% for the C_5–12 hydrocarbons with a higher CO conversion of about 95% was obtained for the FeNa_2.0@C catalyst compared to that for other alkali metal-modified Fe@C catalysts. According to the characterization results, the incorporation of alkali metals into Fe@C enhanced the conversion of FeCO₃ to Fe₃O₄, which promoted the formation of the FTS active phase iron carbides. In particular, the strongest interaction of Fe–alkali metal and the highest amount of surface carbon layers were observed after adding an Na promoter into Fe@C in contrast to that observed for K and Li promoters, which strengthened the synergistic effect of Fe–Na metals and the spatial confinement of the core–shell structure, further improving the C_5–12 hydrocarbon selectivity.

A one-pot synthesized Fe@C core–shell catalyst with a sodium promoter exhibited high gasoline-range product selectivity with high FTS activity.

Substrate-induced hydrothermal synthesis of hematite superstructures and their Fischer–Tropsch synthesis performance

Fe foam substrates with different pore densities are used to fabricate versatile α-Fe₂O₃ nanostructures with different Fischer–Tropsch synthesis performance.

Carbon-encapsulated highly dispersed FeMn nanoparticles for Fischer–Tropsch synthesis to light olefins

The peculiar structure of FeMn@C not only facilitates the formation of χ-Fe₅C₂, but it also promotes the product selectivity of light olefins.

Effects of the Functionalization of the Ordered Mesoporous Carbon Support Surface on Iron Catalysts for the Fischer-Tropsch Synthesis of Lower Olefins

Ordered mesoporous carbon (CMK‐3) with different surface modifications is applied as a support for Fe‐based catalysts in the Fischer–Tropsch to olefins synthesis (FTO) with and without sodium and sulfur promoters. Different concentrations of functional groups do not affect the size (3–5 nm) of Fe particles in the fresh catalysts but iron (carbide) supported on N‐enriched CMK‐3 and a support with a lower concentration of functional groups show higher catalytic activity under industrially relevant FTO conditions (340 °C, 10 bar, H₂/CO=2) compared to a support with an O‐enriched surface. The addition of promoters leads to more noticeable enhancements of the catalytic activity (3–5 times higher) and the selectivity to C₂–C₄ olefins (≈2 times higher) than surface functionalization of the support. Nitrogen surface functionalization and removal of surface groups before impregnation and calcination, however, further increase the activity of the catalysts in the presence of promoters. The confinement of the Fe nanoparticles in the mesopores of CMK‐3 restricts but does not fully prevent particle growth and, consequently, the decrease of activity under FTO conditions.

New insights into the effect of sodium on Fe3O4- based nanocatalysts for CO2 hydrogenation to light olefins

Na-containing Fe₃O₄ nanocatalysts show improved performance in CO₂ hydrogenation due to enhanced surface basicity and carburization induced by residual Na.

Effects of calcination and activation conditions on ordered mesoporous carbon supported iron catalysts for production of lower olefins from synthesis gas

Calcination and activation of CMK-3 supported iron catalysts for C₂–C₄ olefins production from syngas is investigated.