A DFT Insight into the Tuning Effect of Potassium Promoter on the Formation of Carbon Atoms via Carburization Gases Dissociation on Iron-Based Catalysts

Gong, Juhui; Cao, Cheng; Sun, Ruiqin; Cui, Linxia; Gao, Rui; Hao, Haigang

doi:10.3390/catal10050527

Cited by 6 publications

(4 citation statements)

References 47 publications

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“…The electron-donating nature of potassium species causes local electron enrichment around the surface iron oxide sites, making them more difficult to be reduced . It is worthwhile to mention that alkali metal oxides such as K 2 O and Na 2 O are usually adopted in previous studies as the model compounds for theoretical calculations. , Although these alkali metal oxides are not present under the practical CO 2 hydrogenation reaction conditions, the alkali metal ions should still exhibit strong electron-donating capability. We also investigated a K 2 CO 3 cluster on the Fe 3 O 4 (111) surface and found a similar electron-donating effect.…”

Section: Resultsmentioning

confidence: 99%

Tunable Carbon Dioxide Activation Pathway over Iron Oxide Catalysts: Effects of Potassium

Tian

Qiu

et al. 2021

Ind. Eng. Chem. Res.

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The activation of CO 2 to form CO, known as the reverse water−gas shift (RWGS) reaction, is an initial and essential step of numerous CO 2 hydrogenation reactions. However, the reaction is challenging, and the underlying CO 2 activation mechanism is usually overlooked when designing new heterogeneous catalysts. In this work, we investigate the effect of potassium, a common alkali metal promoter, on the iron oxide catalysts using a series of (quasi) in situ characterization techniques, kinetic analysis, and first-principles calculations. It is revealed that introducing potassium increases the surface basicity and steers the preferred CO 2 activation reaction route from a "redox" pathway to an "associative" pathway. Understanding the controlling factors and competitiveness of the two CO 2 activation mechanisms can potentially benefit the rational design of CO 2 hydrogenation catalysts.

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Section: Resultsmentioning

confidence: 99%

Tunable Carbon Dioxide Activation Pathway over Iron Oxide Catalysts: Effects of Potassium

Tian

Qiu

et al. 2021

Ind. Eng. Chem. Res.

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“…After recovering the K enrichment on the catalyst surface, all of the characteristic values in the FTS performance were fully restored to normal. These variation trends exactly demonstrated that the K promoter was a key factor in influencing the trends of FTS product selectivity, which restricted the secondary hydrogenation of alkenes and led to more formation of light olefins and long-chain hydrocarbons [52,53]. denoted as Fe@C-1.0-W, with a K residual of 0.1 wt% (Table 4).…”

Section: Catalytic Performance Of Fischer-tropsch Synthesismentioning

confidence: 76%

“…After recovering the K enrichment on the catalyst surface, all of the characteristic values in the FTS performance were fully restored to normal. These variation trends exactly demonstrated that the K promoter was a key factor in influencing the trends of FTS product selectivity, which restricted the secondary hydrogenation of alkenes and led to more formation of light olefins and long-chain hydrocarbons [52,53]. Overall, one extremely facile, green, low-cost synthetic strategy of high-performance FTS catalysts was successfully explored to in situ construct K-Fe3C@C nanohybrids by using only ferric nitrate and pomelo peel without chemical pretreatment.…”

Section: Catalytic Performance Of Fischer-tropsch Synthesismentioning

confidence: 84%

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

et al. 2022

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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.

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“…To obtain full carburization, H 2 is needed to remove oxygen coming from CO dissociation as H 2 O. Such reactions can be favored by opportune doping: in particular, potassium doping favors CO dissociation on iron and its carburization [246]. Also, cobalt can be carburized to CoC 2 using pure CO at 490-500 K, while only partial carburization occurs using syngas [142,247].…”

Section: The Adsorption and Activation Of Comentioning

confidence: 99%

Mechanistic and Compositional Aspects of Industrial Catalysts for Selective CO2 Hydrogenation Processes

Busca,

Spennati,

Riani

et al. 2024

Catalysts

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The characteristics of industrial catalysts for conventional water-gas shifts, methanol syntheses, methanation, and Fischer-Tropsch syntheses starting from syngases are reviewed and discussed. The information about catalysts under industrial development for the hydrogenation of captured CO2 is also reported and considered. In particular, the development of catalysts for reverse water-gas shifts, CO2 to methanol, CO2-methanation, and CO2-Fischer-Tropsch is analyzed. The difference between conventional catalysts and those needed for pure CO2 conversion is discussed. The surface chemistry of metals, oxides, and carbides involved in this field, in relation to the adsorption of hydrogen, CO, and CO2, is also briefly reviewed and critically discussed. The mechanistic aspects of the involved reactions and details on catalysts’ composition and structure are critically considered and analyzed.

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A DFT Insight into the Tuning Effect of Potassium Promoter on the Formation of Carbon Atoms via Carburization Gases Dissociation on Iron-Based Catalysts

Cited by 6 publications

References 47 publications

Tunable Carbon Dioxide Activation Pathway over Iron Oxide Catalysts: Effects of Potassium

Tunable Carbon Dioxide Activation Pathway over Iron Oxide Catalysts: Effects of Potassium

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

Mechanistic and Compositional Aspects of Industrial Catalysts for Selective CO2 Hydrogenation Processes

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