Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and ...Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and gasoline.Herein we demonstrate that the product can be steered toward liquefied petroleum gas(LPG) with a selectivity up to 89% in hydrocarbons especially propane selectivity reaching 80% at CO conversion of 63% using ZnCrOx-H-SSZ-39 catalyst.Interestingly, the quantity of the acid sites of SSZ-39 does not influence obviously the hydrocarbon distribution but the strength is crucial for selective formation of propane.This finding provides an alternative route of LPG synthesis from a variety of carbon resources via syngas.展开更多
The oxide-zeolite process provides a promising way for one-step production of aromatics from syngas,whereas the reasons for the dramatic effect of intimacy between oxide and zeolite in the composite catalyst on the pr...The oxide-zeolite process provides a promising way for one-step production of aromatics from syngas,whereas the reasons for the dramatic effect of intimacy between oxide and zeolite in the composite catalyst on the product selectivity are still unclear. In order to explore the optimal intimacy and the essential influence factors, ZnCrOxcombined with ZSM-5 are employed to prepare the composite catalysts with different distances between the two components by changing the mixing methods. An aromatic selectivity of 74%(with CO conversion to be 16%) is achieved by the composite catalyst when the intimacy is in the range of nanometer. A so-called ‘iterative reactions’ mechanism of intermediates over oxides is then proposed and studied: the intermediate chemical can undergo a hydrogenation reaction on oxide.So the shorter the intermediates stay on oxide, the more of chance for C-C coupling takes place on zeolite to form aromatics. Moreover, the aero-environments of reaction is found to impact on the extent of iterative reaction as well. Therefore, when the intimacy between the two components changes, the extent of iterative reactions vary, resulting in alteration of product distribution. This work provides new insight in understanding the mechanisms during the complex process of OX-ZEO composite catalysis and sheds light to the design of a high-yield catalyst for synthetization of aromatics from syngas.展开更多
ZEO-1,the first stable aluminosilicate zeolite with extra-large pores,marks a great breakthrough in the zeolite community after decades of exploration and endeavors,opening possibilities for processing bulky substrate...ZEO-1,the first stable aluminosilicate zeolite with extra-large pores,marks a great breakthrough in the zeolite community after decades of exploration and endeavors,opening possibilities for processing bulky substrates.However,the long synthesis cycle and relatively low reproducibility hinder the wide application of this intriguing material.This work developed a‘deficient fluoride approach’for ZEO-1 zeolite synthesis by adding a small amount of fluoride to induce a charge imbalance between the OSDA and fluoride.This approach significantly accelerates crystallization(15 times faster than the reported method)and achieves higher reproducibility than the originally reported protocol.Crystallization kinetics studies demonstrate the accelerating effect of stoichiometrically deficient fluoride anions on the nucleation and crystallization process.The ZEO-1 zeolites synthesized via the‘deficient fluoride approach’show catalytic activity for phenol alkylation with tert-butyl alcohol comparable to that of ZEO-1LCS,but the products are evenly distributed,suggesting that more Brønsted acid sites might have been successfully introduced in the 16 MR channels.This work provides an incentive for feasible academic study and application of ZEO-1.展开更多
Aromatics are important basic chemicals. However, direct conversion of syngas via the conventional Fischer-Tropsch synthesis produces little aromatics. We presented herein that a bifunctional composite of ZSM-5 in com...Aromatics are important basic chemicals. However, direct conversion of syngas via the conventional Fischer-Tropsch synthesis produces little aromatics. We presented herein that a bifunctional composite of ZSM-5 in combination with Zn Cr Oxcatalyzes syngas conversion to aromatics. Particularly, ZSM-5 crystals with a sheet-like morphology can enhance significantly the aromatization activity. The lower length ratio of the b/a axes of the crystals, the more aromatics form but without influencing the selectivity of small molecules such as CH4 and C2–C4. Since the acid properties and the Al chemical environment were not altered while the morphology changed, the enhanced aromatic selectivity is likely attributed to the favored diffusion of aromatics in these sheet-like crystals.展开更多
The sugar components and their dynamic variation in the developing grains of sweet corn(Zea mays L. seccharata Sturt)and normal corn (Zea mays L. indentata Sturt) were compared. There are WSP (water-soluble polysaccha...The sugar components and their dynamic variation in the developing grains of sweet corn(Zea mays L. seccharata Sturt)and normal corn (Zea mays L. indentata Sturt) were compared. There are WSP (water-soluble polysaccharides), sucrose, fructose, glucose, mannitol and sorbitol in both sweet corn and normal corn, but no maltose. Two components with different degrees of polymerization (D. P. N) were detected in the sweet corn; only one of them was detected in the normal corn 20 days after pollination. With the development of grains, the total soluble sugar content(TSS)in sweet corn increased, but in normal corn it decreased. The dynamic variation of WSP, sucrose, glucose, fructose, mannitol and sorbitol in sweet and normal corn grains are different. The contents of sugar components in the sweet corn grains are higher than that in the normal corn. Sweet corn accumulates less starch than normal corn.展开更多
基金supported by the Ministry of Science and Technology of China (No.2017YFB0602201)the Chinese Academy of Sciences (XDA21020400)+2 种基金the National Natural Science Foundation of China (Grant nos.91645204, 21425312 and 21621063)the Youth Innovation Promotion Association of Chinese Academy of Sciences (2019184)the INCOE (International Network of Centers of Excellence) project coordinated by BASF SE
文摘Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and gasoline.Herein we demonstrate that the product can be steered toward liquefied petroleum gas(LPG) with a selectivity up to 89% in hydrocarbons especially propane selectivity reaching 80% at CO conversion of 63% using ZnCrOx-H-SSZ-39 catalyst.Interestingly, the quantity of the acid sites of SSZ-39 does not influence obviously the hydrocarbon distribution but the strength is crucial for selective formation of propane.This finding provides an alternative route of LPG synthesis from a variety of carbon resources via syngas.
基金the National Key R&D Program of China(2016YFA0202804)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020400)+2 种基金the National Natural Science Foundation of China(Nos.21506204,21476226)Dalian Science Foundation for Distinguished Young Scholars(2016RJ04)the Youth Innovation Promotion Association CAS for financial support
文摘The oxide-zeolite process provides a promising way for one-step production of aromatics from syngas,whereas the reasons for the dramatic effect of intimacy between oxide and zeolite in the composite catalyst on the product selectivity are still unclear. In order to explore the optimal intimacy and the essential influence factors, ZnCrOxcombined with ZSM-5 are employed to prepare the composite catalysts with different distances between the two components by changing the mixing methods. An aromatic selectivity of 74%(with CO conversion to be 16%) is achieved by the composite catalyst when the intimacy is in the range of nanometer. A so-called ‘iterative reactions’ mechanism of intermediates over oxides is then proposed and studied: the intermediate chemical can undergo a hydrogenation reaction on oxide.So the shorter the intermediates stay on oxide, the more of chance for C-C coupling takes place on zeolite to form aromatics. Moreover, the aero-environments of reaction is found to impact on the extent of iterative reaction as well. Therefore, when the intimacy between the two components changes, the extent of iterative reactions vary, resulting in alteration of product distribution. This work provides new insight in understanding the mechanisms during the complex process of OX-ZEO composite catalysis and sheds light to the design of a high-yield catalyst for synthetization of aromatics from syngas.
基金The ZeoMat Group acknowledges the starting grant provided by the Qingdao Institute of Bioenergy and Bioprocess Technology and the support from the Shandong Energy Institute(SEI S202107)P.L.acknowledges the support from the Qingdao New Energy Shandong Laboratory of International Cooperation Project(QNESL ICP 202305)V.V.and P.L.acknowledge the collaboration within the Sino-French International Research Network‘Zeolites’framework.The authors are indebted to Yida Zhou and Shutao Xu from Dalian Institute of Chemical Physics for collecting the 19F NMR data.
文摘ZEO-1,the first stable aluminosilicate zeolite with extra-large pores,marks a great breakthrough in the zeolite community after decades of exploration and endeavors,opening possibilities for processing bulky substrates.However,the long synthesis cycle and relatively low reproducibility hinder the wide application of this intriguing material.This work developed a‘deficient fluoride approach’for ZEO-1 zeolite synthesis by adding a small amount of fluoride to induce a charge imbalance between the OSDA and fluoride.This approach significantly accelerates crystallization(15 times faster than the reported method)and achieves higher reproducibility than the originally reported protocol.Crystallization kinetics studies demonstrate the accelerating effect of stoichiometrically deficient fluoride anions on the nucleation and crystallization process.The ZEO-1 zeolites synthesized via the‘deficient fluoride approach’show catalytic activity for phenol alkylation with tert-butyl alcohol comparable to that of ZEO-1LCS,but the products are evenly distributed,suggesting that more Brønsted acid sites might have been successfully introduced in the 16 MR channels.This work provides an incentive for feasible academic study and application of ZEO-1.
基金financially supported by the Ministry of Science and Technology of China(no.2017YFB0602201)the National Natural Science Foundation of China(Grant no.21425312,91645204 and 21621063)
文摘Aromatics are important basic chemicals. However, direct conversion of syngas via the conventional Fischer-Tropsch synthesis produces little aromatics. We presented herein that a bifunctional composite of ZSM-5 in combination with Zn Cr Oxcatalyzes syngas conversion to aromatics. Particularly, ZSM-5 crystals with a sheet-like morphology can enhance significantly the aromatization activity. The lower length ratio of the b/a axes of the crystals, the more aromatics form but without influencing the selectivity of small molecules such as CH4 and C2–C4. Since the acid properties and the Al chemical environment were not altered while the morphology changed, the enhanced aromatic selectivity is likely attributed to the favored diffusion of aromatics in these sheet-like crystals.
文摘The sugar components and their dynamic variation in the developing grains of sweet corn(Zea mays L. seccharata Sturt)and normal corn (Zea mays L. indentata Sturt) were compared. There are WSP (water-soluble polysaccharides), sucrose, fructose, glucose, mannitol and sorbitol in both sweet corn and normal corn, but no maltose. Two components with different degrees of polymerization (D. P. N) were detected in the sweet corn; only one of them was detected in the normal corn 20 days after pollination. With the development of grains, the total soluble sugar content(TSS)in sweet corn increased, but in normal corn it decreased. The dynamic variation of WSP, sucrose, glucose, fructose, mannitol and sorbitol in sweet and normal corn grains are different. The contents of sugar components in the sweet corn grains are higher than that in the normal corn. Sweet corn accumulates less starch than normal corn.
