Direct synthesis of higher oxygenates via syngas over zinc oxide modified CoMn-based catalysts

Qi, Xingzhen; Lin, Tiejun; Gong, Kuanping; Wang, Xinxing; Yu, Fei; An, Yunlei; Tang, Zhiyong; Zhong, Liangshu

doi:10.1016/j.apcata.2022.118925

Cited by 8 publications

(7 citation statements)

References 49 publications

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“…The phase structure of various supports and catalysts at different stages (calcined, reduced and spent) was characterized by XRD. As shown in Figure a–e, the XRD patterns of calcined catalysts (blue lines) showed similar characteristic peaks of Co 2 ZnO 4 (PDF#23–1390) and Co 2 MnO 4 (PDF#01–1130) phases, which indicated that cobalt species existed in the form of composite oxides . After reduction, the diffraction peaks ascribed to the CoO phase (PDF#43–1004) at 2θ of 36.5, 42.4, and 61.5° were observed (pink lines).…”

Section: Resultsmentioning

confidence: 69%

“…The effluent gas was analyzed online and the nongas products were analyzed offline. The detailed analysis process was referred to in our previous work …”

Section: Methodsmentioning

confidence: 99%

“…Higher oxygenates composed of terminal linear α-aldehyde and alcohol with two and more carbon atoms (C 2+ OH) have widespread applications. − The traditional route to obtain higher oxygenates via petroleum is a complex catalytic process with multiple steps, mainly including petroleum cracking to light olefins, polymerization to long-chain olefins, hydroformylation to aldehydes, and further hydrogenation to alcohols. Compared with the traditional production route, one-step synthesis of higher oxygenates from syngas conversion (also defined as higher alcohols synthesis, HAS) provides a more effective, relatively facile, and ecofriendly process. , Generally, for a heterogeneous HAS catalytic reaction, the ideal catalyst should provide dual active sites for both CO dissociative and associative adsorptions, in which the dissociative adsorption facilitates the splitting of the CO bond to generate alkyl species, and the associative adsorption enhances the oxygenate formation by inserting a CO bond into alkyl fragments. − Furthermore, there are many consecutive and parallel reactions in the HAS reaction, and the energy barrier of CH x hydrogenation is usually lower than that of CO insertion, leading to lower oxygenate selectivity . Therefore, regulating the reaction network by catalyst design to achieve a great synergistic effect of different active sites for the preferential formation of higher oxygenates via direct syngas conversion remains challenging.…”

Section: Introductionmentioning

confidence: 99%

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Regulating Oxygen Vacancies for Enhanced Higher Oxygenate Synthesis via Syngas

Qi,

Lin,

et al. 2023

ACS Catal.

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Constructing highly efficient dual active sites for preferential formation of higher oxygenates via direct syngas conversion remains a grand challenge. Herein, we reported that the regulation of oxygen vacancy density of metal–oxide support could effectively promote the production of oxygenates. Compared with an inert SiO2-supported Co-based catalyst, the rutile TiO2-supported catalyst with abundant oxygen vacancies exhibited up to 44.7% CO conversion with the selectivity and space–time yield (STY) of the oxygenate increased to 43.4 wt % and 50 mg gcat. –1 h–1, respectively. Further studies established a nearly linear relationship between the density of the oxygen vacancy and the atomic ratio of Co2+/Co0 or the STY of oxygenated products. Characterization confirmed that the oxygen vacancies not only promote CO adsorption, dissociation, and subsequently the carburization of cobalt species to form Co2C but also create a C-rich and H-poor local microchemical environment that benefits CO associative adsorption and CO bond insertion to form oxygenates. The synergistic effect of oxygen vacancies and the Co0/Co2C interface site contributed to the observed enhanced performance for direct syngas conversion to higher oxygenates.

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Section: Resultsmentioning

confidence: 69%

“…The effluent gas was analyzed online and the nongas products were analyzed offline. The detailed analysis process was referred to in our previous work …”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Regulating Oxygen Vacancies for Enhanced Higher Oxygenate Synthesis via Syngas

Qi,

Lin,

et al. 2023

ACS Catal.

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“…Zhao et al designed a Co@Co 2 C nanostructure on Mn-promoted Co/AC model catalyst for direct synthesis of higher alcohols, and the maximum selectivity to alcohols and olefins reached ∼60% . The Co–Co 2 C interface catalysts derived from CoMn-based oxides were also investigated for HAS reaction in our previous works. ,,, However, it is still difficult to obtain high oxygenate selectivity as well as high CO conversion over the monometallic catalysts.…”

Section: Resultsmentioning

confidence: 99%

“…43 The Co−Co 2 C interface catalysts derived from CoMn-based oxides were also investigated for HAS reaction in our previous works. 7,23,44,45 However, it is still difficult to obtain high oxygenate selectivity as well as high CO conversion over the monometallic catalysts.…”

Section: ■ Introductionmentioning

confidence: 99%

Maximizing the Interface of Dual Active Sites to Enhance Higher Oxygenate Synthesis from Syngas with High Activity

et al. 2023

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Selective synthesis of higher oxygenates from syngas provides a promising route for the conversion of nonpetroleum carbon resources into valuable chemicals. However, it remains a grand challenge to design highly efficient and stable dual-sites structures to promote the production of higher oxygenates. Herein, we reported an effective method to maximize the interface of dual active sites via designing the structure of alloy carbide derived from the FeCo layered double hydroxide precursor. Cobalt atoms were well-distributed and doped into Fe 2 C to form (Fe x Co y ) 2 C alloy carbide. The atomic-scale contact Fe−Co interfacial sites could achieve a >35% oxygenate selectivity at a CO conversion of >80% during 200 h of running, and a high space−time yield of 183.9 mg/g cat. /h for oxygenates with 95.6% being the C 2+ OH fraction was obtained. The kinetic study confirmed that the apparent activation energy of (Fe x Co y ) 2 C alloy carbide was lower than that of separated Fe 2 C-Co 2 C dual sites. This work provides a strategy for the design of an effective catalyst for selective synthesis of higher oxygenates from syngas by tuning the interface of dual active sites at an atomic level.

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