Toward Understanding and Simplifying the Reaction Network of Ketene Production on ZnCr<sub>2</sub>O<sub>4</sub> Spinel Catalysts

Fu, Xianliang; Xiao, Jianping

doi:10.1021/acs.jpcc.1c07375

Cited by 9 publications

(10 citation statements)

References 32 publications

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“…Density functional theory (DFT) calculations were carried out to further understand the effect of the crystallographic structure of MnGaO x on CO hydrogenation mechanism. Following the same methodology as our previous work, [21,24] we first screened the adsorption energy of the two key adsorbates, i.e., CO* and O* as descriptors on different crystal facets of MnGa 2 O 4 , including (111), ( 110), (100), and (311) (Figure S16). The results indicate that the MnGaO x -Spinel (111) (Figure 5A) and MnGaO x -SS (Mn-doped Ga 2 O 3 (110)) (Figure 5B) with both Mn and Ga sites exposed are the most likely surfaces for CO activation (Figure S17 and Table S7), consistent with the HRTEM observation (Figure 1E and Figure S4C).…”

Section: Resultsmentioning

confidence: 99%

Tuning the Crystal Phase to Form MnGaO_x‐Spinel for Highly Efficient Syngas to Light Olefins

et al. 2023

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The oxide-zeolite (OXZEO) catalyst design concept has been demonstrated in an increasing number of studies as an alternative avenue for direct syngas conversion to light olefins. We report that face-centered cubic (FCC) MnGaO x -Spinel gives 40 % CO conversion, 81 % light olefins selectivity, and a 0.17 g g cat À 1 h À 1 spacetime yield of light olefins in combination with SAPO-18. In comparison, solid solution MnGaO x (characterized by Mn-doped hexagonal close-packed (HCP) Ga 2 O 3 ) with a similar chemical composition gives a much inferior activity, i.e., the specific surface activity is one order of magnitude lower than the spinel oxide. Photoluminescence (PL), in situ Fourier-transform infrared (FT-IR), and density functional theory (DFT) calculations indicate that the superior activity of MnGaO x -Spinel can be attributed to its higher reducibility (higher concentration of oxygen vacancies) and the presence of coordinatively unsaturated Ga 3 + sites, which facilitates the dissociation of the CÀ O bond via a more efficient ketene-acetate pathway to light olefins.

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Section: Resultsmentioning

confidence: 99%

Tuning the Crystal Phase to Form MnGaO_x‐Spinel for Highly Efficient Syngas to Light Olefins

et al. 2023

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“…This finding is supported by a parallel microkinetic modeling study on the ZnCr 2 O 4 (111) surface, which is calculated to be the most stable surface under reaction conditions. 294 Accordingly, the surface coverage by CH 3 CO (ketene precursor) is 11 times higher than that by CH 3 O (methanol precursor).…”

Section: Integration Of Methanol and Dme Carbonylation With Co X Hydr...mentioning

confidence: 99%

“…With the intention to determine if the key intermediate is indeed ketene or methanol, theoretical understanding of the ZnCrO x systems is needed. 293,294 DFT calculations and microkinetic simulations on the highly reduced ZnCr 2 O 4 (110) surface revealed the propensity of CO to absorb on the O vacancy sites, followed by reaction with H to form a CHO surface species. 293 The distinction between ketene and methanol is dependent on what happens next to the CHO surface species.…”

Section: Integration Of Methanol and Dme Carbonylation With Co X Hydr...mentioning

confidence: 99%

The Oxygenate-Mediated Conversion of CO_xto Hydrocarbons─On the Role of Zeolites in Tandem Catalysis

Xie,

Olsbye

2023

Chem. Rev.

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Decentralized chemical plants close to circular carbon sources will play an important role in shaping the postfossil society. This scenario calls for carbon technologies which valorize CO 2 and CO with renewable H 2 and utilize process intensification approaches. The single-reactor tandem reaction approach to convert CO x to hydrocarbons via oxygenate intermediates offers clear benefits in terms of improved thermodynamics and energy efficiency. Simultaneously, challenges and complexity in terms of catalyst material and mechanism, reactor, and process gaps have to be addressed. While the separate processes, namely methanol synthesis and methanol to hydrocarbons, are commercialized and extensively discussed, this review focuses on the zeolite/zeotype function in the oxygenate-mediated conversion of CO x to hydrocarbons. Use of shape-selective zeolite/ zeotype catalysts enables the selective production of fuel components as well as key intermediates for the chemical industry, such as BTX, gasoline, light olefins, and C 3+ alkanes. In contrast to the separate processes which use methanol as a platform, this review examines the potential of methanol, dimethyl ether, and ketene as possible oxygenate intermediates in separate chapters. We explore the connection between literature on the individual reactions for converting oxygenates and the tandem reaction, so as to identify transferable knowledge from the individual processes which could drive progress in the intensification of the tandem process. This encompasses a multiscale approach, from molecule (mechanism, oxygenate molecule), to catalyst, to reactor configuration, and finally to process level. Finally, we present our perspectives on related emerging technologies, outstanding challenges, and potential directions for future research. CONTENTS 1. Introduction 11775 2. Methanol-Mediated CO x Conversion to Hydrocarbons 11783 2.1. A Short Introduction to the MTH Process 11783 2.2. Integration of the MTH Reactions with CO x Hydrogenation 11787 3. Dimethyl-Ether-Mediated CO x Conversion to Hydrocarbons 11791 3.1. Dimethyl Ether to Hydrocarbons (DTH) 11791 3.2. Methanol to Dimethyl Ether (MTD) 11793 3.3. Integration of the MTD and DTH Reactions with CO x Hydrogenation 11794 4. Ketene-Mediated CO x Conversion to Hydrocarbons 11798 4.1. Methanol Carbonylation 11798 4.2. DME Carbonylation 11799 4.3. Integration of Methanol and DME Carbonylation with CO x Hydrogenation 11803 5.

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“…Fischer–Tropsch synthesis (FTS) is a traditional strategy to convert syngas into hydrocarbons over Fe and Co catalysts; however, the Anderson–Schulz–Flory (ASF) model in FTS limits the selectivity of C 2–4 hydrocarbons (including olefins and paraffins), which is no more than 58%. , Recently, an elegant oxide–zeolite (OX-ZEO) route was proposed to selectively convert syngas into olefins (STO), liquid fuels and aromatics depending on the topologies of the zeolites, , which breaks the ASF distribution in FTS. A number of metal oxides, such as ZnCrO x , , Zn–ZrO 2 , , ZnAlO x ,, and MnGaO x , − and several kinds of zeolites, including SAPO-34, − SAPO-18, , AlPO-18, and SSZ-13, , have been intensively studied. In such an OX-ZEO catalyst system, the metal oxide is responsible for the syngas activation to generate intermediates like methanol and ketene, while the zeolite plays the role in tandem conversion of intermediates to target products .…”

Section: Introductionmentioning

confidence: 99%

Rational Design of SAPO-34 Zeolite in Bifunctional Catalysts for Syngas Conversion into Light Olefins

Meng

Liang

Wang

et al. 2022

Ind. Eng. Chem. Res.

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Zeolites in bifunctional catalysts composed of a metal oxide and a zeolite (OX-ZEO) play a crucial role in conversion of generated intermediates during the reaction. In this work, a series of SAPO-34 zeolites were hydrothermally synthesized using different templates, i.e., morpholine (MOR), diethylamine (DEA), tetraethyl ammonium hydroxide (TEAOH), and their mixture. The effects of templates, SiO 2 /Al 2 O 3 molar ratios on the zeolite structure, and surface properties were investigated, and the catalytic performance over SAPO-34 combined with GaZrO x oxide for the conversion of syngas into light olefins was explored. SAPO-34 synthesized using a MOR or DEA template exhibits large particle sizes, while the TEAOH or TEAOH-contained templates contribute to the small particle size and large specific surface area. SAPO-34 with small particle sizes benefits to enhance the CO conversion and C 2−4 = selectivity, and the increase in Brønsted acid site amounts slightly reduced the C 2−4 = selectivity when the particle size of SAPO-34 is small and varied a little. SAR0.4-TD with a SiO 2 /Al 2 O 3 ratio of 0.4 exhibits the highest space−time yield of light olefins of 261.0 mL•h −1 •g −1 at a CO conversion of 28.0%. Moreover, the carbon deposition and the evolution of carbonaceous species for the spent GaZrO x /SAPO-34 catalyst were studied to analyze the reason for catalyst deactivation.

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Toward Understanding and Simplifying the Reaction Network of Ketene Production on ZnCr₂O₄ Spinel Catalysts

Cited by 9 publications

References 32 publications

Tuning the Crystal Phase to Form MnGaO_x‐Spinel for Highly Efficient Syngas to Light Olefins

Tuning the Crystal Phase to Form MnGaO_x‐Spinel for Highly Efficient Syngas to Light Olefins

The Oxygenate-Mediated Conversion of CO_xto Hydrocarbons─On the Role of Zeolites in Tandem Catalysis

Rational Design of SAPO-34 Zeolite in Bifunctional Catalysts for Syngas Conversion into Light Olefins

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Toward Understanding and Simplifying the Reaction Network of Ketene Production on ZnCr2O4 Spinel Catalysts

Cited by 9 publications

References 32 publications

Tuning the Crystal Phase to Form MnGaOx‐Spinel for Highly Efficient Syngas to Light Olefins

Tuning the Crystal Phase to Form MnGaOx‐Spinel for Highly Efficient Syngas to Light Olefins

The Oxygenate-Mediated Conversion of COxto Hydrocarbons─On the Role of Zeolites in Tandem Catalysis

Rational Design of SAPO-34 Zeolite in Bifunctional Catalysts for Syngas Conversion into Light Olefins

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Toward Understanding and Simplifying the Reaction Network of Ketene Production on ZnCr₂O₄ Spinel Catalysts

Tuning the Crystal Phase to Form MnGaO_x‐Spinel for Highly Efficient Syngas to Light Olefins

Tuning the Crystal Phase to Form MnGaO_x‐Spinel for Highly Efficient Syngas to Light Olefins

The Oxygenate-Mediated Conversion of CO_xto Hydrocarbons─On the Role of Zeolites in Tandem Catalysis