The exploration of highly efficient catalysts based on nano-sized Ti-rich titanosilicate zeolites with controllable active titanium species is of great importance in zeolite catalytic reactions.Herein,we reported an e...The exploration of highly efficient catalysts based on nano-sized Ti-rich titanosilicate zeolites with controllable active titanium species is of great importance in zeolite catalytic reactions.Herein,we reported an efficient and facile synthesis of nano-sized Ti-rich TS-1(MFI)zeolites by replacing tetrabutyl orthotitanate(TBOT)with tetrabutyl orthotitanate tetramer(TBOT-tetramer)as the titanium source.The introduced TBOT-tetramer slowed down the zeolite crystallization process,and accordingly balanced the rate of incorporating Ti and the crystal growth and inhibited the massive formation of anatase species.Notably,the prepared Ti-rich TS-1 zeolite sample had a Si/Ti as low as 27.6 in contrast to conventional one with a molar ratio of 40.The TBOT-tetramer endowed the titanosilicate zeolites with enriched active titanium species and enlarged external surface area.It also impeded the formation of anatase species,resulting in superior catalytic behavior toward the oxidative desulfurization of dibenzothiophene compared with the conventional TS-1 zeolite counterpart prepared with TBOT.展开更多
With the increasingly stringent standards for limiting sulfide content in liquid fuels,oxidative desulfurization(ODS)has become a promising ultra-deep desulfurization process in fuel desulfurization.TS-1 zeolites show...With the increasingly stringent standards for limiting sulfide content in liquid fuels,oxidative desulfurization(ODS)has become a promising ultra-deep desulfurization process in fuel desulfurization.TS-1 zeolites show great potential as catalysts for ODS reactions,due to its remarkable oxidation activity at low temperatures and pressure.However,the inherent microporous structure of conventional TS-1 zeolites restricts the mass transportation and renders the active sites in the microporous space of TS-1 zeolites inaccessible for bulky aromatic organosulfur compounds.Fabrication of hierarchical TS-1 zeolites by incorporating meso-/macropores into microporous TS-1 zeolites is an effective strategy to improve mass transportability.In recent years,abundant efforts have been dedicated to developing synthetic strategies of hierarchical TS-1 zeolite,thereby improving its catalytic performance in the ODS process.This mini-review addresses the synthetic methods of hierarchical TS-1 catalysts and their catalytic performance in the ODS reactions.In addition,some current problems and prospects of synthesis routes for constructing hierarchical TS-1 catalysts have also been revised.We expect this mini-review to shed light on the more efficient preparation strategies of hierarchical TS-1 zeolites for the ODS process.展开更多
Simultaneous achievement of constructing mesopores and eliminating anatase is a long-term pursuit for enhancing the catalytic performance of TS-1.Here,we developed an aromatic compounds-mediated synthesis method to pr...Simultaneous achievement of constructing mesopores and eliminating anatase is a long-term pursuit for enhancing the catalytic performance of TS-1.Here,we developed an aromatic compounds-mediated synthesis method to prepare anatase-free and hierarchical TS-1 for olefin epoxidation.A series of hierarchical TS-1 zeolites were prepared by introducing aromatic compounds containing different functional groups via the crystallization process.The formation of intercrystalline mesopores and insertion of titanium into framework were facilitated at different extent.The synergistic coordination of carboxyl and hydroxyl in aromatic compounds with Ti(OH)4 realizes the uniform distribution of titanium species and eliminates the generation of anatase.Noteworthily,eight machine learning models were trained to reveal the mechanism of additive functional groups and preparation conditions on anatase formation and microstructure optimization.The prediction accuracy of most models can reach more than 80%.Benefiting from the larger mesopore volumes(0.37 cm3⋅g−1)and higher content of framework Ti species,TS-DHBDC-48h samples exhibit a higher catalytic performance than other zeolites,giving 1-hexene conversion of 49.3%and 1,2-epoxyhenane selectivity of 99.9%.The paper provides a facile aromatic compounds-mediated synthesis strategy and promotes the application of machine learning toward the design and optimization of new zeolites.展开更多
The exploration of high-efficient catalysts based on hierarchical Ti-containing zeolites with optimized active titanium species distribution is of great value in enhancing the epoxidation of bulky olefins. Herein, hie...The exploration of high-efficient catalysts based on hierarchical Ti-containing zeolites with optimized active titanium species distribution is of great value in enhancing the epoxidation of bulky olefins. Herein, hierarchical TS-1(MFI) zeolite with an extra-large external surface area(210 m2/g) and highly active octahedral- coordinated Ti species was prepared via organic base-assisted sequential post-treatment. Such a catalyst afforded a high turnover number value(TON, 114) in 1-octene epoxidation reaction, which was over twice than that(53) of the untreated conventional microporous TS-1 parent. According to the detailed characterization results, we revealed the hierarchical porosity construction effect of tetrapropylamonium hydroxide(TPAOH) treatment(first step) and the octahedral-coordinated Ti species fabrication effect of ethylamine(EA) treatment(second step) under hydrothermal condition. Such a facile post-treatment strategy reported in this work may provide guidance for the rational synthesis of TS-1 zeolite with enhanced catalytic activity.展开更多
The acid-base titration,atomic force microscopy(AFM),contact angle technique,energy dispersive X-ray(EDX)and electron probe microanalysis(EPMA)were performed to check the existence of the gel-layer on the chitosan sur...The acid-base titration,atomic force microscopy(AFM),contact angle technique,energy dispersive X-ray(EDX)and electron probe microanalysis(EPMA)were performed to check the existence of the gel-layer on the chitosan surface after it was dipped in aqueous TPAOH solution as well as in TS-1 synthesis solution.The evolution of TS-1 monolayer and multi-layered film on the chitosan surface was studied using SEM imaging at different stages during hydrothermal reactions.Experimental evidence for the formation mechanism of supported zeolite films and membranes revealed that a gel-layer enriched with TPA cations and TS-1 precursors was first formed on the chitosan surface,followed by the nucleation within the gel-layer especially on the chitosan surface.The nuclei formed on the chitosan surface were further transformed into crystalline particles and TS-1 crystal grains.The nuclei beyond the chitosan surface subsequently grew up,leading to the formation of multi-layered TS-1 film with preferential b-orientation.The result is significant for engineering the microstructure of supported zeolite films and membranes in hydrothermal reactions.展开更多
A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnOx in the propane dehydr genati...A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnOx in the propane dehydr genation(PDH) reaction. Catalysts were characterized by means ofN2 adsorption-desorption, XRD, SEM, TEM, XPS, UV-Vis, and Raman spectroscopy. The effect of different contents of TS-1 on PDH was investigated, and the optimal amount of TS-1 was determined to be 10%. The catalyst with TS-1 content of 10% showed the highest PDH activity and the initial conversion of propane over it can achieve 54.5%, higher than those over TS-1 or SB A-16-supported ones. The superior catalytic performance of Pt-SnOx/TS-1 @SBA-16 is related to the synergistic effect of the excellent mass transfer performance through the hierarchical porous structure, suitable acid acidity and electronic effect of Ti species.展开更多
Generating hollow structure inside titanium silicalite-1(TS-1)is a widely used method to improve its liquid-phase oxidation catalytic performance in industry.However,traditional dissolution-recrystallization method us...Generating hollow structure inside titanium silicalite-1(TS-1)is a widely used method to improve its liquid-phase oxidation catalytic performance in industry.However,traditional dissolution-recrystallization method usually required a large amount of aqueous solution of organic template,leading to unfavorable polluted waste,low production efficiency,and high manufacture cost.Here,a facile and environmental friendly strategy was proposed for the post-synthesis of hollow TS-1 zeolite with a solventfree method utilizing NH4HCO3 and tetrapropylammounium bromide as selective etching agents,which reduced the usage of organic template and avoided the liquid waste.The high crystallinity,the microporous structure,and the active Ti sites were preserved at a high product yield(>93%).The formation mechanism of hollow structure was also investigated by exploring effects of different reactants and experimental parameters.Meanwhile,the obtained hollow TS-1 showed an outstanding performance in the epoxidation of 1-hexene in comparison to the parent zeolite.展开更多
基金the National Natural Science Foundation of China, China (Grant 21920102005, 22288101, and 21835002)the 111 Project, China (B17020)+2 种基金the European Union through the European Research Council, European Union (grant ERC-AdG-2014-671093, SynCatMatch)the Spanish Government through “Severo Ochoa”, Spain (SEV2016-0683, MINECO) for supporting this workthe financial support from China Scholarship Council, China
文摘The exploration of highly efficient catalysts based on nano-sized Ti-rich titanosilicate zeolites with controllable active titanium species is of great importance in zeolite catalytic reactions.Herein,we reported an efficient and facile synthesis of nano-sized Ti-rich TS-1(MFI)zeolites by replacing tetrabutyl orthotitanate(TBOT)with tetrabutyl orthotitanate tetramer(TBOT-tetramer)as the titanium source.The introduced TBOT-tetramer slowed down the zeolite crystallization process,and accordingly balanced the rate of incorporating Ti and the crystal growth and inhibited the massive formation of anatase species.Notably,the prepared Ti-rich TS-1 zeolite sample had a Si/Ti as low as 27.6 in contrast to conventional one with a molar ratio of 40.The TBOT-tetramer endowed the titanosilicate zeolites with enriched active titanium species and enlarged external surface area.It also impeded the formation of anatase species,resulting in superior catalytic behavior toward the oxidative desulfurization of dibenzothiophene compared with the conventional TS-1 zeolite counterpart prepared with TBOT.
基金supported by the National Natural Science Foundation of China(21971082)the Jilin Province Science and Technology Development Plan(20200201096JC and 20190201229JC)+1 种基金the China Postdoctoral Science Foundation(2019T120235 and 2018M640280)for supporting this workthe 111 Project(B17020)。
文摘With the increasingly stringent standards for limiting sulfide content in liquid fuels,oxidative desulfurization(ODS)has become a promising ultra-deep desulfurization process in fuel desulfurization.TS-1 zeolites show great potential as catalysts for ODS reactions,due to its remarkable oxidation activity at low temperatures and pressure.However,the inherent microporous structure of conventional TS-1 zeolites restricts the mass transportation and renders the active sites in the microporous space of TS-1 zeolites inaccessible for bulky aromatic organosulfur compounds.Fabrication of hierarchical TS-1 zeolites by incorporating meso-/macropores into microporous TS-1 zeolites is an effective strategy to improve mass transportability.In recent years,abundant efforts have been dedicated to developing synthetic strategies of hierarchical TS-1 zeolite,thereby improving its catalytic performance in the ODS process.This mini-review addresses the synthetic methods of hierarchical TS-1 catalysts and their catalytic performance in the ODS reactions.In addition,some current problems and prospects of synthesis routes for constructing hierarchical TS-1 catalysts have also been revised.We expect this mini-review to shed light on the more efficient preparation strategies of hierarchical TS-1 zeolites for the ODS process.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFB3500700SINOPEC Research Institute of Petroleum Processing+3 种基金Natural Science Foundation of Guangdong Province of China,Grant/Award Number:2022A1515011918Scientific and Technological Innovation Foundation of Shunde Graduate SchoolUniversity of Science and Technology Beijing,Grant/Award Number:BK20AE003Fundamental Research Funds for the Central Universities,Grant/Award Number:FRF-IDRY-20-004。
文摘Simultaneous achievement of constructing mesopores and eliminating anatase is a long-term pursuit for enhancing the catalytic performance of TS-1.Here,we developed an aromatic compounds-mediated synthesis method to prepare anatase-free and hierarchical TS-1 for olefin epoxidation.A series of hierarchical TS-1 zeolites were prepared by introducing aromatic compounds containing different functional groups via the crystallization process.The formation of intercrystalline mesopores and insertion of titanium into framework were facilitated at different extent.The synergistic coordination of carboxyl and hydroxyl in aromatic compounds with Ti(OH)4 realizes the uniform distribution of titanium species and eliminates the generation of anatase.Noteworthily,eight machine learning models were trained to reveal the mechanism of additive functional groups and preparation conditions on anatase formation and microstructure optimization.The prediction accuracy of most models can reach more than 80%.Benefiting from the larger mesopore volumes(0.37 cm3⋅g−1)and higher content of framework Ti species,TS-DHBDC-48h samples exhibit a higher catalytic performance than other zeolites,giving 1-hexene conversion of 49.3%and 1,2-epoxyhenane selectivity of 99.9%.The paper provides a facile aromatic compounds-mediated synthesis strategy and promotes the application of machine learning toward the design and optimization of new zeolites.
基金This work was supported by the National Natural Science Foundation of China (Nos.21835002,21621001,22001090)the "111" Project of China(No.B17020)the China Postdoctoral Science Foundation(No.2021T140259).
文摘The exploration of high-efficient catalysts based on hierarchical Ti-containing zeolites with optimized active titanium species distribution is of great value in enhancing the epoxidation of bulky olefins. Herein, hierarchical TS-1(MFI) zeolite with an extra-large external surface area(210 m2/g) and highly active octahedral- coordinated Ti species was prepared via organic base-assisted sequential post-treatment. Such a catalyst afforded a high turnover number value(TON, 114) in 1-octene epoxidation reaction, which was over twice than that(53) of the untreated conventional microporous TS-1 parent. According to the detailed characterization results, we revealed the hierarchical porosity construction effect of tetrapropylamonium hydroxide(TPAOH) treatment(first step) and the octahedral-coordinated Ti species fabrication effect of ethylamine(EA) treatment(second step) under hydrothermal condition. Such a facile post-treatment strategy reported in this work may provide guidance for the rational synthesis of TS-1 zeolite with enhanced catalytic activity.
基金supported by the National Natural Science Foundation of China(20636030,20776100 and 20776108)
文摘The acid-base titration,atomic force microscopy(AFM),contact angle technique,energy dispersive X-ray(EDX)and electron probe microanalysis(EPMA)were performed to check the existence of the gel-layer on the chitosan surface after it was dipped in aqueous TPAOH solution as well as in TS-1 synthesis solution.The evolution of TS-1 monolayer and multi-layered film on the chitosan surface was studied using SEM imaging at different stages during hydrothermal reactions.Experimental evidence for the formation mechanism of supported zeolite films and membranes revealed that a gel-layer enriched with TPA cations and TS-1 precursors was first formed on the chitosan surface,followed by the nucleation within the gel-layer especially on the chitosan surface.The nuclei formed on the chitosan surface were further transformed into crystalline particles and TS-1 crystal grains.The nuclei beyond the chitosan surface subsequently grew up,leading to the formation of multi-layered TS-1 film with preferential b-orientation.The result is significant for engineering the microstructure of supported zeolite films and membranes in hydrothermal reactions.
基金Supported by the National Natural Science Foundation of China(Nos.21845201,21761162016,21603148).
文摘A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnOx in the propane dehydr genation(PDH) reaction. Catalysts were characterized by means ofN2 adsorption-desorption, XRD, SEM, TEM, XPS, UV-Vis, and Raman spectroscopy. The effect of different contents of TS-1 on PDH was investigated, and the optimal amount of TS-1 was determined to be 10%. The catalyst with TS-1 content of 10% showed the highest PDH activity and the initial conversion of propane over it can achieve 54.5%, higher than those over TS-1 or SB A-16-supported ones. The superior catalytic performance of Pt-SnOx/TS-1 @SBA-16 is related to the synergistic effect of the excellent mass transfer performance through the hierarchical porous structure, suitable acid acidity and electronic effect of Ti species.
基金This work was supported by the National Natural Science Foundation of China(Nos.21875140,21835002,21522105,and 51861145313)the Shanghai Science and Technology Plan(No.21DZ2260400)+4 种基金the China Ministry of Science and Technology(No.2021YFA1501401)The authors thank the support from Analytical Instrumentation Center(No.SPSTAIC10112914)SPST,ShanghaiTech UniversityThe authors also thank Prof.Osamu Terasaki and CħEM SPST,ShanghaiTech University(No.EM02161943)for scientific and characterization support.Y.F.thanks Junyan Li(Jilin University)for his assistance in 3D tomographic data collection.
文摘Generating hollow structure inside titanium silicalite-1(TS-1)is a widely used method to improve its liquid-phase oxidation catalytic performance in industry.However,traditional dissolution-recrystallization method usually required a large amount of aqueous solution of organic template,leading to unfavorable polluted waste,low production efficiency,and high manufacture cost.Here,a facile and environmental friendly strategy was proposed for the post-synthesis of hollow TS-1 zeolite with a solventfree method utilizing NH4HCO3 and tetrapropylammounium bromide as selective etching agents,which reduced the usage of organic template and avoided the liquid waste.The high crystallinity,the microporous structure,and the active Ti sites were preserved at a high product yield(>93%).The formation mechanism of hollow structure was also investigated by exploring effects of different reactants and experimental parameters.Meanwhile,the obtained hollow TS-1 showed an outstanding performance in the epoxidation of 1-hexene in comparison to the parent zeolite.
