Enhancing the light olefin selectivity and extending the catalytic durability remain critical challenges for ZSM-5 zeolites in the methanol to olefins(MTO)conversion,while the inherent diffusion restriction along the ...Enhancing the light olefin selectivity and extending the catalytic durability remain critical challenges for ZSM-5 zeolites in the methanol to olefins(MTO)conversion,while the inherent diffusion restriction along the MFI b-axis direction and poor coke accommodation are the main limiting factors.In this work,we developed a hierarchically singlecrystalline ZSM-5 sheet architecture that features an interconnected multiscale porosity and a remarkably reduced baxis thickness(<50 nm),as quantitatively verified by threedimensional(3D)electron tomography.Real-time confocal laser scanning microscopy(CLSM)tracking demonstrated a significant enhancement in molecular diffusivity compared to conventional micron-sized ZSM-5 counterparts(Micro-ZSM5).This engineered structure allows abundant aluminum sites to be distributed on the highly accessible diffusion pathways,and displays an enlarged coke accommodation of 16.31 wt%with a coke deposition rate of 0.59 mg g^(-1) h^(-1),which was only one third of that in the Micro-ZSM-5.In a continuous MTO process,this novel hierarchical ZSM-5 sheet(Hier-ZSM-5-S)kept an average selectivity to ethylene and propene of 63.5%on stream for 22.2 h(WHSV=3.6 h−1,T=480℃),which was 19%higher and 6.5 times longer than those of Micro-ZSM-5,respectively.This hierarchically shortened b-axis structure establishes a generalizable paradigm for enhanced diffusion and coke accommodation in a precisely designed pore system,which is expected to be adjusted and applied for varying reactions.展开更多
IN XRD patterns of clay minerals, a phenomenon that strong peaks often have (00l) and(hkl) (k=3n) indices and show symmetric figures can be seen commonly, while a minorityof reflection peaks (hkl) (k≠3n) are comparat...IN XRD patterns of clay minerals, a phenomenon that strong peaks often have (00l) and(hkl) (k=3n) indices and show symmetric figures can be seen commonly, while a minorityof reflection peaks (hkl) (k≠3n) are comparatively weak and wide, and show展开更多
基金financially supported by the National Key R&D Program of China (2022YFB3504000)National Natural Science Foundation of China (22293022, 22402155, U22B6011)+4 种基金Program of Introducing Talents of Discipline to Universities-Plan 111 (B20002) from the Ministry of Science and Technology and the Ministry of Education of China,Natural Science Foundation of Hubei Province (2023AFB605, 2025AFB033)Dawning Program of Wuhan (2023020201020306)supported by the European Commission Interreg V France-Wallonie-Vlaanderen project“Depollut Air”,the Program Win2Wal (TCHARBONACTIF:2110120)Wallonia Region of Belgium,and the National Key R&D Program Intergovernmental Technological Innovation Special Cooperation Project Wallonia-Brussels/China (MOST)(SUB/2021/IND493971/524448)Hubei Provincial Department of Education for the “Chutian Scholar” program。
文摘Enhancing the light olefin selectivity and extending the catalytic durability remain critical challenges for ZSM-5 zeolites in the methanol to olefins(MTO)conversion,while the inherent diffusion restriction along the MFI b-axis direction and poor coke accommodation are the main limiting factors.In this work,we developed a hierarchically singlecrystalline ZSM-5 sheet architecture that features an interconnected multiscale porosity and a remarkably reduced baxis thickness(<50 nm),as quantitatively verified by threedimensional(3D)electron tomography.Real-time confocal laser scanning microscopy(CLSM)tracking demonstrated a significant enhancement in molecular diffusivity compared to conventional micron-sized ZSM-5 counterparts(Micro-ZSM5).This engineered structure allows abundant aluminum sites to be distributed on the highly accessible diffusion pathways,and displays an enlarged coke accommodation of 16.31 wt%with a coke deposition rate of 0.59 mg g^(-1) h^(-1),which was only one third of that in the Micro-ZSM-5.In a continuous MTO process,this novel hierarchical ZSM-5 sheet(Hier-ZSM-5-S)kept an average selectivity to ethylene and propene of 63.5%on stream for 22.2 h(WHSV=3.6 h−1,T=480℃),which was 19%higher and 6.5 times longer than those of Micro-ZSM-5,respectively.This hierarchically shortened b-axis structure establishes a generalizable paradigm for enhanced diffusion and coke accommodation in a precisely designed pore system,which is expected to be adjusted and applied for varying reactions.
文摘IN XRD patterns of clay minerals, a phenomenon that strong peaks often have (00l) and(hkl) (k=3n) indices and show symmetric figures can be seen commonly, while a minorityof reflection peaks (hkl) (k≠3n) are comparatively weak and wide, and show
