Kinetic studies for elucidation of the promoter effect of alkali in Fischer-Tropsch iron catalysts

Herzog, K.

doi:10.1016/0021-9517(89)90038-9

Cited by 30 publications

(17 citation statements)

References 6 publications

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“…2,3 In the Fischer-Tropsch reactions, potassium increases the selectivity of iron-based catalysts. 4 Similar promotion effects of alkali metals have also been reported for oxidation reactions over oxide catalysts. 5 In general, the alkali promotion effect is attributed to the changes in the electronic features of active components and adsorbed reactant molecules, 6-9 so enhancing their catalytic performance.…”

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confidence: 69%

The promotion effect of isolated potassium atoms with hybridized orbitals in catalytic oxidation

Huang

et al. 2015

Chem. Commun.

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confidence: 69%

The promotion effect of isolated potassium atoms with hybridized orbitals in catalytic oxidation

Huang

et al. 2015

Chem. Commun.

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“…The apparent chain growth probability factor (i.e., α), as defined by the ASF model, depends on several factors, including vapor-liquid equilibrium (VLE), type of reactor, diffusional limitations, olefin re-adsorption, etc. [21,[58][59][60][61][62][63][64][65][66][67][68][69][70][71][72]. Oxygenated compounds vaporize at higher temperatures (when compared at similar carbon chain length) and therefore will be more severely affected than hydrocarbons [73].…”

Section: Anderson Schulz and Florymentioning

confidence: 99%

Fischer–Tropsch: Product Selectivity–The Fingerprint of Synthetic Fuels

et al. 2019

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The bulk of the products that were synthesized from Fischer–Tropsch synthesis (FTS) is a wide range (C1–C70+) of hydrocarbons, primarily straight-chained paraffins. Additional hydrocarbon products, which can also be a majority, are linear olefins, specifically: 1-olefin, trans-2-olefin, and cis-2-olefin. Minor hydrocarbon products can include isomerized hydrocarbons, predominantly methyl-branched paraffin, cyclic hydrocarbons mainly derived from high-temperature FTS and internal olefins. Combined, these products provide 80–95% of the total products (excluding CO2) generated from syngas. A vast number of different oxygenated species, such as aldehydes, ketones, acids, and alcohols, are also embedded in this product range. These materials can be used to probe the FTS mechanism or to produce alternative chemicals. The purpose of this article is to compare the product selectivity over several FTS catalysts. Discussions center on typical product selectivity of commonly used catalysts, as well as some uncommon formulations that display selectivity anomalies. Reaction tests were conducted while using an isothermal continuously stirred tank reactor. Carbon mole percentages of CO that are converted to specific materials for Co, Fe, and Ru catalysts vary, but they depend on support type (especially with cobalt and ruthenium) and promoters (especially with iron). All three active metals produced linear alcohols as the major oxygenated product. In addition, only iron produced significant selectivities to acids, aldehydes, and ketones. Iron catalysts consistently produced the most isomerized products of the catalysts that were tested. Not only does product selectivity provide a fingerprint of the catalyst formulation, but it also points to a viable proposed mechanistic route.

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“…12,13 Occasionally, alkali ions can give a similar promotion effect in oxidation reactions over oxide catalysts. 14,15 Actually, depending on the electronic states and the dispersion states, alkali ions can also function as active components in catalytic reactions for controlling soot PMs and VOCs emissions.…”

Section: ■ Introductionmentioning

confidence: 98%

“…Although alkali-rich PMs have important contributions to both primary PMs emissions and formation of secondary inorganic aerosol, alkali metals often serve as promoters in heterogeneous catalysis, which can give rise to the positive effects on many important catalytic reactions. , Occasionally, alkali ions can give a similar promotion effect in oxidation reactions over oxide catalysts. , Actually, depending on the electronic states and the dispersion states, alkali ions can also function as active components in catalytic reactions for controlling soot PMs and VOCs emissions. − For instance, the K + ions have been identified as catalytically active sites in the soot combustion, which can activate gaseous oxygen and enhance the oxidation activity of the catalysts . Upon arriving at the high or even atomic dispersion state on surfaces, alkalis become so active that they facilitate dissociation of molecular oxygen (O 2 ) by transferring electrons to the π* bonding orbitals of O 2 molecule, ,, and dissociated atomic oxygen is often extremely active in oxidation reactions of the soot PMs and the VOCs.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Control of Typical Particulate Matters and Volatile Organic Compounds Emissions from Simulated Biomass Burning

Chen

Tian

Zhou

et al. 2016

Environ. Sci. Technol.

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Emissions of particulate matters (PMs) and volatile organic compounds (VOCs) from open burning of biomass often cause severe air pollution; a viable approach is to allow biomass to burn in a furnace to collectively control these emissions, but practical control technologies for this purpose are lacking. Here, we report a hollandite manganese oxide (HMO) catalyst that can efficiently control both typical PMs and VOCs emissions from biomass burning. The results reveal that typical alkali-rich PMs such as KCl particles are disintegrated and the K(+) ions are trapped in the HMO "single-walled" tunnels with a great trapping capacity. The K(+)-trapping HMO increases the electron density of the lattice oxygen and the redox ability, thus promoting the combustion of soot PMs and the oxidation of typical VOCs such as aldehydes and acetylates. This could pave a way to control emissions from biomass burning concomitant with its utilization for energy or heat generation.

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Kinetic studies for elucidation of the promoter effect of alkali in Fischer-Tropsch iron catalysts

Cited by 30 publications

References 6 publications

The promotion effect of isolated potassium atoms with hybridized orbitals in catalytic oxidation

The promotion effect of isolated potassium atoms with hybridized orbitals in catalytic oxidation

Fischer–Tropsch: Product Selectivity–The Fingerprint of Synthetic Fuels

Catalytic Control of Typical Particulate Matters and Volatile Organic Compounds Emissions from Simulated Biomass Burning

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