CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jun Mou,Xingqi Fan,Fei Liu,Xiaodan Wang,Tianxiang Zhao,Peng Chen,Ziwei Li,Chunliang Yang,Jianxin Cao
The direct conversion of CO 2 hydrogenation to lower olefins via methanol as an intermediate is of great significance, but challenges still remain. Herein, we present a binary Mn 2 O 3 -ZnO oxide, which is responsible for catalytic hydrogenation of CO 2 to methanol. After combination of Mn 2 O 3 -ZnO and SAPO-34 molecular sieve, the catalytic reaction displays a markable increase. CO 2 adsorption by alkaline nature, followed by oxygen vacancy activation and synergistic hydrogenation over the binary Mn 2 O 3 -ZnO oxide are the prerequisites for the tandem reaction. However, the tandem spacing between oxide and molecular sieve plays a crucial role, because the suitable intimacy can induce enhanced methanol formation as intermediate via tandem dynamics effect, causing an apparent limitation for reverse water gas shift reaction at high temperature. The optimum mass ratio of 3:1 for two phases demonstrates that more components of binary oxide are needed to improve the rate of CO 2 hydrogenation to methanol, aiming to balance the two-step tandem reaction. Finally, under conditions of 380 ℃, 3 MPa and 3600 mL/g cat /h, 20%Mn 2 O 3 -ZnO/SAPO-34 tandem catalyst is obtained by physical ball milling after 15 min, with excellent stability, sulfur tolerance and catalytic performance with CO 2 conversion at almost 30%, lower olefins selectivity of 80.2% (propylene/ethylene = 5.6:1), and single-pass yield of 10.7%.
研究领域:
催化化学
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能源化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2020
·
IF 4.982
Yakun Liu,Chi Ma,Chengxiang Shi,Lun Pan,Junjian Xie,Si Gong,Yong-Chao Zhang,Genkuo Nie,Xiangwen Zhang,Ji-Jun Zou
With the rapid development of spacecraft such as rocket, it is increasingly important to develop high-energy and sustainable fuels. Biofuels synthesized from biomass derivatives provide great convenience for sustainable development. In this work, we reported a route for synthesis of high-energy cyclopropane bio-kerosene by cyclopropanation of myrcene with zinc carbenoid. The reaction conditions including reaction time, reaction temperature, solvent and molar ratio were optimized. Finally, a tricyclic cyclopropane bio-kerosene was synthesized with 69.8% yield under optimum conditions (i.e. zinc carbenoid synthesis temperature of −15 °C, cyclopropanation temperature of 25 °C and solvent of dichloromethane). Importantly, this bio-kerosene possesses a high specific impulse of 328.25 s, much better than the commercial rocket kerosene RP-1, as well as a high net-heat-value of 43.4 MJ/kg and good low-temperature properties.
研究领域:
能源生物学
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有机化学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Chemical Science and Engineering
·
2024
·Vol. 18
·期 10
·1-10
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IF 4.3
Zhao Qiao,Wang Hongyu,Liang Haoting,Han Xiaoxue,Wei Chongyang,Wang Shiwei,Wang Yue,Huang Shouying,Ma Xinbin
Lower olefins, produced from syngas through Fischer-Tropsch synthesis, has been gaining worldwide attention as a non-petroleum route. However, the process demonstrates limited selectivity for target products. Herein, a hybrid catalyst system utilizing Fe-based catalyst and SAPO-34 was shown to enhance the selectivity toward lower olefins. A comprehensive study was conducted to examine the impact of various operating conditions on catalytic performance, such as space velocity, pressure, and temperature, as well as catalyst combinations, including loading pattern, and mass ratio of metal and zeolite. The findings indicated that the addition of SAPO-34 was beneficial for enhancing catalytic activity. Furthermore, compared with AlPO-34 zeolite, the strong-acid site on SAPO-34 was identified to crack the long-chain hydrocarbons, thus contributing to the lower olefin formation. Nevertheless, an excess of strong-acid sites was found to detrimentally impact the selectivity of lower olefins, attributed to the increased aromatization and polymerization of lower olefins. The detailed analysis of a hybrid catalyst in Fischer-Tropsch synthesis provides a practical strategy for improving lower olefins selectivity, and has broader implications for the application of hybrid catalyst in diverse catalytic systems.
研究领域:
化学工程
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催化科学
✓ 已验证
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2024
·
IF 3.7
Yi Jing Jia,Jin Quan Tao,Hao Ran Liu,Wen Bin Huang,Rongpeng Yao,Miaomiao Niu,Rongrong Li,Qiang Wei,Ya Song Zhou
To enhance the CO 2 hydrogenation activity and low-carbon olefin selectivity of Fe-based catalysts, a strategy involving the use of metal promoters to modulate the structure of active metal centers in catalyst preparation was proposed. The incipient wetness impregnation method was used to introduce modifying agents K and/or Co into the Fe/Al 2 O 3 catalyst. Characterization techniques such as XRD, BET, SEM, HRTEM, H 2 -TPR, XPS, CO 2 -TPD, NH 3 -TPD, and TG were employed to investigate the effects of the modifying agents on the dispersion, reducibility, electronic properties, and acid–base properties of active metal species. Furthermore, the influence of K and Co modification on the CO 2 hydrogenation activity and low-carbon olefin selectivity of Fe/Al 2 O 3 catalysts was explored. The results revealed that the introduction of K generated more basic sites and electron-rich active metal centers in the catalyst, facilitating the adsorption and activation of CO 2 , while suppressing the hydrogenation of olefins and the formation of methane, thus improving the selectivity towards low-carbon olefins. Co promoter facilitated the dispersion of Fe species, exposing more active sites and enhancing the FTS reaction activity, leading to more CO being converted into C 2+ hydrocarbon products. Under the synergistic effect of K and Co, the CO 2 conversion activity of the Fe-based catalyst significantly increased, achieving a CO 2 conversion rate of 37%, while the selectivity towards C 2 -C 4= increased to 31.9%.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of CO2 Utilization
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2020
·
IF 5.993
Chengyi Dai,Xiao Zhao,Borui Hu,Xinbao Zhang,Qunxing Luo,Xinwen Guo,Xiaoxun Ma
Capturing and utilization of carbon dioxide (CO 2 ) not only leads to effective use of carbon resources, but also alleviates environmental pollution caused by increasing concentration of CO 2 , thus making it a hot research topic in recent years. In this study, a series of highly dispersed iron-cobalt (Fe-Co) catalysts was prepared by ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) modification, which could efficiently convert CO 2 into high value-added chemicals (C 2 -C 4 = and C 5 -C 11 ). X-ray diffraction (XRD) analysis showed that the addition of a small amount of Co and EDTA-2Na contributed to enhance the sintering resistance of Fe species. During the calcination process, EDTA 4− can be decomposed into small organic molecules with reducibility, thus promoting the reduction of iron species. The CO temperature-programmed desorption (CO-TPD) results showed that cobalt enhanced the adsorption and activation of intermediate CO on Na x Fe-Co catalyst, thereby promoting the catalytic conversion of CO 2 . The complexation of EDTA promotes the synergistic effect of Fe-Co bimetals, enhances the chemical adsorption of CO 2 . Sodium in EDTA-2Na promotes the surface basicity of the catalysts, which is favored for improving the product distribution of hydrocarbons. At lower H 2 /CO 2 (1/1) ratio, the EDTA-2Na modified Fe-Co/Al 2 O 3 catalyst exhibited high conversion of CO 2 (32.8 %) and excellent selectivity toward high value-added chemicals. The selectivity of by-product CO was only 8.1 %; and C 2 -C 4 = (32.5 %) and C 5 -C 11 (46.3 %) accounted for ∼79 % selectivity among the hydrocarbons generated.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Xiaodan Zhang,Fei Yu,Jie Zhang,Zhiyong Tang,Yuhan Sun
Wall-coating is an attractive approach for immobilizing catalyst into microchannels due to potential enhancement in heat and mass transfer and a small pressure drop. A novel hybrid method was thus developed for efficiently wall-coating special cobalt carbide catalyst into FeCrAlloy microchannels on the direct production of lower olefins from syngas. The effect of pretreatment was investigated to form a uniform Al2O3 layer on the surface of FeCrAlloy substrate. The small loss of coated catalyst layer in the mechanical adherence test by exposing the FeCrAlloy substrate to a fast nitrogen flow indicated its outstanding stability in the immobilization of cobalt carbide catalyst. The coating catalyst exhibited a stable and good activity after reaching the steady state. Additionally, calculations revealed that the wall-coated and fixed-bed microreactors had comparable mass transfer factor jD, but the former provided a five times larger heat transfer factor jH and 100 times lower pressure drop per unit length, confirming in detail the advantages of wall-coating. The proposed wall-coating strategy can be applied for immobilizing other catalyst within metallic microchannels, providing a practical technical solution for industrial implementation of microreactors.
研究领域:
化学工程
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催化材料
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Yiqi Xu,Yishu Jiang,Hao Xu,Qingtao Wang,Weimin Huang,Haihua He,Yuanyuan Zhai,Shuxia Di,Lingling Guo,Xiaoliang Xu,Jia Zhao,Feng Feng,Qunfeng Zhang,Xiaonian Li
Designing the electron-rich palladium active site is of great importance to enhance the selectivity of ethylene in acetylene semi-hydrogenation. In this work, ionic liquids, the effective electronic modifier, were mingled with palladium solution to be immobilized on Al 2 O 3 by incipient impregnation method. X-ray photoelectron spectra characterization was conducted to characterize the structure of catalysts, suggesting that some ionic liquids can form unique carbene structure. The catalytic results showed that those immobilized ionic liquids that can form unique carbene structure exhibited much higher selectivity of ethylene than those cannot. The above results were obtained because carbene can donor the electron to palladium, enriching the electron density of palladium and therefore facilitating the desorption of ethylene. The findings of the unique carbene structure derived from ionic liquids in this work provide an efficient strategy to design the catalyst to improve the selectivity of the intermediate in other partial hydrogenationreactions.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2019
·
IF 7.723
Yulong Zhang,Chenxi Cao,Chao Zhang,Zhengpai Zhang,Xianglin Liu,Zixu Yang,Minghui Zhu,Bo Meng,Jing Xu,Yi-Fan Han
The establishment of structure-performance relationship of catalysts during a full life cycle is highly desirable for catalyst design and understanding of nature of active sites. As a case study, lower olefins synthesis directly from CO 2 hydrogenation (CTO) was performed over iron catalyst and the catalyst structure evolution during its life cycle has been comprehensively studied. Particularly, operando techniques allow direct observation of the continuous phase transition during activation (Fe 2 O 3 → Fe 5 C 2 ), reaction and deactivation (Fe 5 C 2 → Fe 3 O 4 ), and regeneration (Fe 3 O 4 → Fe 5 C 2 ) process, respectively. After a combined CO 2 -CO regeneration, 91.8% of the initial activity and 97.7% of the initial C 2 –C 4 olefins selectivity were recovered. Our results indicate that the Fe 5 C 2 phase is the active phase for C 2 –C 4 olefins production. The iron carbide phases are irreversibly oxidized to Fe 3 O 4 under CTO conditions, which is the major factor responsible for the catalyst deactivation. This study not only reveals the dynamic structure evolution of iron catalyst during the full life cycle in CTO, but also endows deep insight into the underlying deactivation mechanism.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ChemCatChem
·
2017
·Vol. 9
·期 16
·3144-3152
·
IF 4.803
Yong Yuan,Shouying Huang,Hongyu Wang,Yifan Wang,Jian Wang,Jing Lv,Zhenhua Li,Xinbin Ma
Graphical Engineered catalysts : A monodisperse nano-Fe 3 O 4 on α-Al 2 O 3 catalyst synthesized by a novel two-step method of thermal decomposition and impregnation shows enhanced activity and stability for the Fischer–Tropsch synthesis to lower olefins. The effects of promoters (K and S) and size are investigated as well. The Fischer–Tropsch synthesis to lower olefins (FTO) is a desirable nonpetroleum-based route to produce basic chemicals. A novel two-step method was applied to synthesize iron-based supported catalysts, which is to prepare nano-Fe 3 O 4 first by thermal decomposition method and sequentially load them on α-Al 2 O 3 by impregnation. TEM and XRD results manifested that the controllable, uniform Fe 3 O 4 nanoparticles are monodispersed on the surface of α-Al 2 O 3 . H 2 -TPR demonstrated that the reduction of Fe species was facilitated because of the weak interaction between Fe species and the support. These superior properties contribute to an enhanced catalytic activity and stability compared with the catalyst prepared by directly impregnating ammonium iron citrate on α-Al 2 O 3 . Then, the effect of promoters was investigated at the same Fe loading and nanoparticle size. The appropriate addition of K could enhance the catalytic activity and suppress the secondary hydrogenation. On the contrary, S has a negative impact on CO conversion and strongly decreases C 5+ selectivity. Particularly, the combination of K and S could obtain more pronounced CO conversion and higher lower olefins selectivity (≈40 %). Furthermore, size effects were explored by precisely tailoring the iron oxide particle size with the Fe loading kept constant. It was found that 12.0 nm nano-Fe 3 O 4 on α-Al 2 O 3 with or without K plus S promoters showed the best catalytic activity among the catalysts with different particle size.
研究领域:
催化化学
·
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
JACS Au
·
2024
·
IF 8.5
Hanqing Xie,Kaifeng Liu,Zhengqiang Li,Zhi Wang,Chunyu Wang,Fengxi Li,Weiwei Han,Lei Wang
In this study, we developed a machine-learning-aided protein design strategy for engineering Vitreoscilla hemoglobin (VHb) as carbene transferase. A Natural Language Processing (NLP) model was used for the first time to construct an algorithm (EESP, enzyme enantioselectivity score predictor) and predict the enantioselectivity of VHb. We identified critical amino acid residue sites by molecular docking and established a simplified mutation library by site-saturated mutagenesis. Based on the simplified mutant library, the trianed EESP scored 160,000 virtual mutants, and 15 predicted high-score mutants were chosen for experimental validation. Among these mutants, VHb-WK (Y29W/P54K) demonstrated the highest diastereoselectivity and enantioselectivity of carbene transferase for the olefin cyclopropanation in aqueous conditions. Subsequently, molecular dynamics simulations were performed to explore the interaction between protein and substrates, finding that the high enantioselectivity of VHb-WK stems from the interactions of R47, Q53, and K84, which narrows the entrance of the enzyme’s pocket, favoring the restriction of the formation of reaction intermediates. Integrating the NLP model and enzyme modification offers significant advantages by reducing economic costs and workloads associated with the protein engineering process.
研究领域:
生物化学
·
计算生物学
·
酶工程
✓ 已验证
DOI
PubMed
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Fei Yuan,Guanghui Zhang,Jie Zhu,Fanshu Ding,Anfeng Zhang,Chunshan Song,Xinwen Guo
Direct conversion of carbon dioxide (CO 2 ) into lower olefins (C 2 -C 4 = ) is highly attractive as a sustainable production route for its great significance in greenhouse gas emission control and fossil fuel substitution. Fe-based catalysts have been extensively studied in CO 2 hydrogenation, which usually show unsatisfactory selectivity toward lower olefins. Here we present a high-dispersion catalyst precursor CoFe 2 O 4 with Na (Na-CoFe 2 O 4 ) that offers C 2 -C 4 = space time yield as high as 2.88 μmol C2-C4= g cat −1 s -1 and olefin to paraffin ratio about 6 at CO 2 conversion higher than 41 %. High dispersion and the intimate contact between Fe and Co sites help inhibit the formation of methane, and favor a higher selectivity of C 2 + hydrocarbons, especially lower olefins. The presence of Na further promotes chain growth and suppresses the direct hydrogenation of Fe-(CH 2 ) n intermediates. A superior stability over 100 h was observed, demonstrating the promising potential of this catalyst for industrial applications.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Feng Jiang,Shanshan Wang,Jiao Zheng,Bing Liu,Yuebing Xu,Xiaohao Liu
Promoters, such as Na and Mn, play an important role in governing the active phase and catalytic performance of cobalt-based FTS catalyst. In this work, the dependence of the promotional effect of promoters on supports has been investigated by using the carbon and silica supported cobalt-based catalysts in the presence of Na, Mn, and both Na and Mn promoters, respectively. The characterization results of H 2 -TPR, CO-TPD and XRD profiles together with the FTS performances demonstrate the strong dependence of the promotional effect of promoter on the type of support used. The carbon support, which shows weak cobalt-support interaction, facilitates the manifestation of the effect of promoter. In detail, Mn can promote the formation of Co 2 C sites at the conditions of 260 °C, 0.5 MPa and lower H 2 /CO ratio, resulting from the promoted CO adsorption and subsequent dissociation. Thus, the suppressed adsorption of H 2 and the promoted surface dissociative C* concentration enhances the selectivities to lower olefins (C 2 = -C 4 = ) and C 5+ with a decrease in methane selectivity. Interestingly, the further addition of Na promoter shows synergistic effect of Na and Mn promoter on remarkably increasing selectivity to lower olefins due to the obviously suppressed chain growth. This synergistic effect could be observed only at the weak cobalt-carbon interaction with a more obvious effect at lower H 2 /CO ratio in feed gas that favors the increase of Co 2 C sites with mainly exposed facets of (111) and (020). The presence of (020) facet might be more crucial to enhance the formation of lower olefins. However, over silica support with strong cobalt-silica interaction, the promotional effect of Mn is obviously suppressed, which leads to only CoO and metallic Co sites in the FTS reaction and much weaker impact on product selectivity. The further addition of Na into Mn-promoted cobalt catalysts shows similar effect as Na promoter alone in the product selectivity where the chain growth is highly promoted to remarkably suppress methane selectivity and enhance selectivity to C 5+ rather than desired lower olefins. In contrast to carbon support, the strong cobalt-silica interaction leads to less promotional formation of CO 2 via the Boudouard reaction (2CO*→C* + CO 2 ) due to the increased non-dissociative adsorption of CO.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）