The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Xiaojun Bao - One of the best experts on this subject based on the ideXlab platform.
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controlled synthesis of zsm 5 zeolite with an unusual al distribution in framework from natural Aluminosilicate Mineral
Microporous and Mesoporous Materials, 2020Co-Authors: Yanni Zhou, Haiyan Liu, Xiaojun Bao, Yuanyuan Yue, Xiaorong Rao, Haibo ZhuAbstract:Abstract Precisely tuning the location of Al atoms in zeolite framework that plays a critical role in determining the catalytic performance of zeolite based catalysts has attracted considerable attention. In this article, we present an organotemplate-free approach for the controllable synthesis of ZSM-5 zeolite with a high content of Al pairs selectively located at the channel intersections, which is achieved by using a submolten salt (SMS) depolymerized rectorite as both the Al source and heteropical crystalline seeds. The quasi in-situ characterizations tracking the zeolite crystallization process reveal that the depolymerized rectorite with abundant oligomeric Aluminosilicate species and Al–O-(Si–O)1,2-Al sequences plays dual roles in the synthesis of ZSM-5 zeolite. These oligomeric Aluminosilicate species like 5- and 6-membered ring structures serve as the crystalline seeds to promote the zeolite nucleation; simultaneously, the Al–O-(Si–O)1,2-Al sequences are in-situ transformed into the final zeolite framework leading to the generation of numerous Al pairs selectively located at the channel intersections. Such an unusual Al distribution endows the synthesized ZSM-5 zeolite with excellent catalytic performance in methanol to aromatics (MTA) reaction. Our strategy provides a sustainable and efficient way to design and synthesize high-performance zeolites with special framework Al distributions for catalytic applications.
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Mesoporogen-free synthesis of hierarchical sodalite as a solid base catalyst from sub-molten salt-activated Aluminosilicate
Particuology, 2020Co-Authors: Jinbiao Yang, Xiaojun Bao, Yuanyuan Yue, Haiyan LiuAbstract:Abstract A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural Aluminosilicate Mineral without the involvement of any mesoporogen or post-synthesis treatment was developed. This strategy involves three important steps: the first is the depolymerization of an Aluminosilicate Mineral into highly reactive silicon and aluminum species with ideal meso-scale structures through activation of a sub-molten salt. The second step is the hydrolysis and condensation of the activated Aluminosilicate Mineral into zeolitic precursors that also have a meso-scale structure. The third is the rapid zeolitization of the zeolitic precursors through the reversed crystal growth route at room temperature and ambient pressure to form hierarchical sodalite. The physicochemical properties of the as-synthesized sodalite were systematically characterized, and the formation mechanism of the hierarchical pore structure was discussed. When used as a solid base catalyst for Knoevenagel condensation, the as-synthesized sodalite and its potassium ion-exchanged product with hierarchical micro–meso–macroporous structure both exhibited high catalytic activity and product selectivity.
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Template-Free Synthesis and Catalytic Applications of Microporous and Hierarchical ZSM-5 Zeolites from Natural Aluminosilicate Minerals
Industrial & Engineering Chemistry Research, 2017Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Yanni Zhou, Zhu Haibo, Zhengshuai Bai, Xiaojun BaoAbstract:Organic templates play a crucial role in zeolite synthesis, but their use causes serious pollutant emissions and increases product costs. Herein, we report a template-free approach to synthesize both microporous and hierarchical ZSM-5 zeolites from natural Aluminosilicate Mineral, which is achieved by (1) utilizing the mother liquid to construct mesopores without using any mesoscale template and (2) reusing the Si-rich alkali liquor and ion-exchanging solution to improve the atom economy without any alkali/acid liquor discharges. The results show that the resultant zeolites own more open pore channels and less strong acid sites compared with a conventional ZSM-5 zeolite and demonstrate superior catalytic activity in n-octene hydroisomerization. Significantly, compared with the traditional synthesis process, our approach can greatly reduce the material and energy consumptions and pollutant discharges while significantly increase the raw material utilization efficiency, endowing itself as an economic, eco-s...
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green synthesis of zeolites from a natural Aluminosilicate Mineral rectorite effects of thermal treatment temperature
Applied Clay Science, 2014Co-Authors: Haiyan Liu, Pei Yuan, Xiaojun Bao, Gang Shi, Tong ShenAbstract:Abstract This article reports the effects of thermal treatment temperature on the physicochemical properties of a rectorite Mineral and the chemical reactivity and crystallization behavior of the activated rectorite products for zeolite synthesis purposes. The raw rectorite Mineral and its thermal activation products were systematically characterized by XRF, XRD, FTIR and 29Si and 27Al MAS NMR techniques and the resultant zeolites were characterized by XRD technique. The results showed that after being thermally treated in the temperature range of 25–1300 °C, the rectorite experienced the following four stages: dehydration at 150–300 °C, dehydroxylation at 600–700 °C, structure collapse at 1000 °C, and new phase formation at above 1100 °C. Moreover, it was found that after being thermally treated at ca. 1000 °C, the SiO4 tetrahedral units in the rectorite Mineral are distorted, while the AlO6 octahedral units are decomposed and thus the maximum contents of active SiO2 and Al2O3 can be simultaneously achieved, and as a result, zeolite P is obtained when using the rectorite calcined at 1000 °C as the starting material for fabricating zeolites. Our results further revealed that like kaolin rectorite after thermal activation at a suitable temperature can be used for zeolite synthesis and thus demonstrates itself a promising feedstock for the green synthesis of zeolites directly from natural Aluminosilicates without experiencing intermediate chemicals.
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From natural Aluminosilicate Minerals to hierarchical ZSM-5 zeolites: A nanoscale depolymerization–reorganization approach
Journal of Catalysis, 2014Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Li Tiesen, Xiaojun BaoAbstract:In this article, we describe a novel strategy for synthesizing hierarchical ZSM-5 zeolites via the nanoscale depolymerization–reorganization of natural Aluminosilicate Minerals. This strategy involves two important steps: the first is the top-down depolymerization of one aluminum-rich Aluminosilicate Mineral via a novel submolten salt system and one silicon-rich Aluminosilicate Mineral via conventional thermal treatment into nanoscale building blocks, and the second is the bottom-up rearrangement and reorganization of nanoscale building blocks in the synthesis system into hierarchical ZSM-5 zeolites. When used as a fluid catalytic cracking catalyst additive, the resulting ZSM-5 zeolite with hierarchical micro–mesoporous structure exhibited high activity and selectivity for valuable products in preliminary oil refining tests. The salient features of the strategy lie in that it neither involves any inorganic aluminum and silicon salts as precursors nor uses any secondary mesoscale template and post-treatment to create mesopores, thus demonstrating itself to be a green route to synthesizing hierarchical zeolites.
Haiyan Liu - One of the best experts on this subject based on the ideXlab platform.
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controlled synthesis of zsm 5 zeolite with an unusual al distribution in framework from natural Aluminosilicate Mineral
Microporous and Mesoporous Materials, 2020Co-Authors: Yanni Zhou, Haiyan Liu, Xiaojun Bao, Yuanyuan Yue, Xiaorong Rao, Haibo ZhuAbstract:Abstract Precisely tuning the location of Al atoms in zeolite framework that plays a critical role in determining the catalytic performance of zeolite based catalysts has attracted considerable attention. In this article, we present an organotemplate-free approach for the controllable synthesis of ZSM-5 zeolite with a high content of Al pairs selectively located at the channel intersections, which is achieved by using a submolten salt (SMS) depolymerized rectorite as both the Al source and heteropical crystalline seeds. The quasi in-situ characterizations tracking the zeolite crystallization process reveal that the depolymerized rectorite with abundant oligomeric Aluminosilicate species and Al–O-(Si–O)1,2-Al sequences plays dual roles in the synthesis of ZSM-5 zeolite. These oligomeric Aluminosilicate species like 5- and 6-membered ring structures serve as the crystalline seeds to promote the zeolite nucleation; simultaneously, the Al–O-(Si–O)1,2-Al sequences are in-situ transformed into the final zeolite framework leading to the generation of numerous Al pairs selectively located at the channel intersections. Such an unusual Al distribution endows the synthesized ZSM-5 zeolite with excellent catalytic performance in methanol to aromatics (MTA) reaction. Our strategy provides a sustainable and efficient way to design and synthesize high-performance zeolites with special framework Al distributions for catalytic applications.
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Mesoporogen-free synthesis of hierarchical sodalite as a solid base catalyst from sub-molten salt-activated Aluminosilicate
Particuology, 2020Co-Authors: Jinbiao Yang, Xiaojun Bao, Yuanyuan Yue, Haiyan LiuAbstract:Abstract A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural Aluminosilicate Mineral without the involvement of any mesoporogen or post-synthesis treatment was developed. This strategy involves three important steps: the first is the depolymerization of an Aluminosilicate Mineral into highly reactive silicon and aluminum species with ideal meso-scale structures through activation of a sub-molten salt. The second step is the hydrolysis and condensation of the activated Aluminosilicate Mineral into zeolitic precursors that also have a meso-scale structure. The third is the rapid zeolitization of the zeolitic precursors through the reversed crystal growth route at room temperature and ambient pressure to form hierarchical sodalite. The physicochemical properties of the as-synthesized sodalite were systematically characterized, and the formation mechanism of the hierarchical pore structure was discussed. When used as a solid base catalyst for Knoevenagel condensation, the as-synthesized sodalite and its potassium ion-exchanged product with hierarchical micro–meso–macroporous structure both exhibited high catalytic activity and product selectivity.
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Template-Free Synthesis and Catalytic Applications of Microporous and Hierarchical ZSM-5 Zeolites from Natural Aluminosilicate Minerals
Industrial & Engineering Chemistry Research, 2017Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Yanni Zhou, Zhu Haibo, Zhengshuai Bai, Xiaojun BaoAbstract:Organic templates play a crucial role in zeolite synthesis, but their use causes serious pollutant emissions and increases product costs. Herein, we report a template-free approach to synthesize both microporous and hierarchical ZSM-5 zeolites from natural Aluminosilicate Mineral, which is achieved by (1) utilizing the mother liquid to construct mesopores without using any mesoscale template and (2) reusing the Si-rich alkali liquor and ion-exchanging solution to improve the atom economy without any alkali/acid liquor discharges. The results show that the resultant zeolites own more open pore channels and less strong acid sites compared with a conventional ZSM-5 zeolite and demonstrate superior catalytic activity in n-octene hydroisomerization. Significantly, compared with the traditional synthesis process, our approach can greatly reduce the material and energy consumptions and pollutant discharges while significantly increase the raw material utilization efficiency, endowing itself as an economic, eco-s...
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green synthesis of zeolites from a natural Aluminosilicate Mineral rectorite effects of thermal treatment temperature
Applied Clay Science, 2014Co-Authors: Haiyan Liu, Pei Yuan, Xiaojun Bao, Gang Shi, Tong ShenAbstract:Abstract This article reports the effects of thermal treatment temperature on the physicochemical properties of a rectorite Mineral and the chemical reactivity and crystallization behavior of the activated rectorite products for zeolite synthesis purposes. The raw rectorite Mineral and its thermal activation products were systematically characterized by XRF, XRD, FTIR and 29Si and 27Al MAS NMR techniques and the resultant zeolites were characterized by XRD technique. The results showed that after being thermally treated in the temperature range of 25–1300 °C, the rectorite experienced the following four stages: dehydration at 150–300 °C, dehydroxylation at 600–700 °C, structure collapse at 1000 °C, and new phase formation at above 1100 °C. Moreover, it was found that after being thermally treated at ca. 1000 °C, the SiO4 tetrahedral units in the rectorite Mineral are distorted, while the AlO6 octahedral units are decomposed and thus the maximum contents of active SiO2 and Al2O3 can be simultaneously achieved, and as a result, zeolite P is obtained when using the rectorite calcined at 1000 °C as the starting material for fabricating zeolites. Our results further revealed that like kaolin rectorite after thermal activation at a suitable temperature can be used for zeolite synthesis and thus demonstrates itself a promising feedstock for the green synthesis of zeolites directly from natural Aluminosilicates without experiencing intermediate chemicals.
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From natural Aluminosilicate Minerals to hierarchical ZSM-5 zeolites: A nanoscale depolymerization–reorganization approach
Journal of Catalysis, 2014Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Li Tiesen, Xiaojun BaoAbstract:In this article, we describe a novel strategy for synthesizing hierarchical ZSM-5 zeolites via the nanoscale depolymerization–reorganization of natural Aluminosilicate Minerals. This strategy involves two important steps: the first is the top-down depolymerization of one aluminum-rich Aluminosilicate Mineral via a novel submolten salt system and one silicon-rich Aluminosilicate Mineral via conventional thermal treatment into nanoscale building blocks, and the second is the bottom-up rearrangement and reorganization of nanoscale building blocks in the synthesis system into hierarchical ZSM-5 zeolites. When used as a fluid catalytic cracking catalyst additive, the resulting ZSM-5 zeolite with hierarchical micro–mesoporous structure exhibited high activity and selectivity for valuable products in preliminary oil refining tests. The salient features of the strategy lie in that it neither involves any inorganic aluminum and silicon salts as precursors nor uses any secondary mesoscale template and post-treatment to create mesopores, thus demonstrating itself to be a green route to synthesizing hierarchical zeolites.
Ian Mcnulty - One of the best experts on this subject based on the ideXlab platform.
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Microheterogeneity of element distribution and sulfur speciation in an organic surface horizon of a forested Histosol as revealed by synchrotron-based X-ray spectromicroscopy
Organic Geochemistry, 2011Co-Authors: Jörg Prietzel, Jürgen Thieme, David L. Paterson, Ingrid Kögel-knabner, Ian McnultyAbstract:Abstract In recent years, the relevance of physico-chemical heterogeneity patterns in soils at the micron and submicron scale for the regulation of biogeochemical processes has become increasingly evident. For an organic surface soil horizon from a forested Histosol in Germany, microspatial patterns of element distribution (sulfur, phosphorus, aluminium, silicon) and S speciation were investigated by synchrotron-based X-ray spectromicroscopy. Microspatial patterns of S, P, Al and Si contents in the organic topsoil were assessed for a sample region of 50 μm × 30 μm by spatially resolving μ-XRF. Sulfur speciation at four microsites was investigated by focused X-ray absorption near edge structure (μ-XANES) spectroscopy at the S K -edge. The results show a heterogeneous distribution of the investigated elements on the (sub)micron scale, allowing the identification of diatoms, Aluminosilicate Mineral particles and sulfide Minerals in the organic soil matrix. Evaluation of the S K -edge μ-XANES spectra acquired at four different microsites by linear combination fitting revealed a substantial microspatial heterogeneity of S speciation, characterized by the presence of distinct enrichment zones of inorganic sulfide and zones with dominant organic disulfide S within a few micrometers distance, and coexistence of different S species (e.g. reduced inorganic and organic S compounds) at a spatial scale below the resolution of the instrument (60 nm × 60 nm; X-ray penetration depth: 30 μm).
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Microheterogeneity of element distribution and sulfur speciation in an organic surface horizon of a forested Histosol as revealed by synchrotron-based X-ray spectromicroscopy
Organic Geochemistry, 2011Co-Authors: Jörg Prietzel, Jürgen Thieme, David L. Paterson, Ingrid Kögel-knabner, Ian McnultyAbstract:Abstract In recent years, the relevance of physico-chemical heterogeneity patterns in soils at the micron and submicron scale for the regulation of biogeochemical processes has become increasingly evident. For an organic surface soil horizon from a forested Histosol in Germany, microspatial patterns of element distribution (sulfur, phosphorus, aluminium, silicon) and S speciation were investigated by synchrotron-based X-ray spectromicroscopy. Microspatial patterns of S, P, Al and Si contents in the organic topsoil were assessed for a sample region of 50 μm × 30 μm by spatially resolving μ-XRF. Sulfur speciation at four microsites was investigated by focused X-ray absorption near edge structure (μ-XANES) spectroscopy at the S K -edge. The results show a heterogeneous distribution of the investigated elements on the (sub)micron scale, allowing the identification of diatoms, Aluminosilicate Mineral particles and sulfide Minerals in the organic soil matrix. Evaluation of the S K -edge μ-XANES spectra acquired at four different microsites by linear combination fitting revealed a substantial microspatial heterogeneity of S speciation, characterized by the presence of distinct enrichment zones of inorganic sulfide and zones with dominant organic disulfide S within a few micrometers distance, and coexistence of different S species (e.g. reduced inorganic and organic S compounds) at a spatial scale below the resolution of the instrument (60 nm × 60 nm; X-ray penetration depth: 30 μm).
Pei Yuan - One of the best experts on this subject based on the ideXlab platform.
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Template-Free Synthesis and Catalytic Applications of Microporous and Hierarchical ZSM-5 Zeolites from Natural Aluminosilicate Minerals
Industrial & Engineering Chemistry Research, 2017Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Yanni Zhou, Zhu Haibo, Zhengshuai Bai, Xiaojun BaoAbstract:Organic templates play a crucial role in zeolite synthesis, but their use causes serious pollutant emissions and increases product costs. Herein, we report a template-free approach to synthesize both microporous and hierarchical ZSM-5 zeolites from natural Aluminosilicate Mineral, which is achieved by (1) utilizing the mother liquid to construct mesopores without using any mesoscale template and (2) reusing the Si-rich alkali liquor and ion-exchanging solution to improve the atom economy without any alkali/acid liquor discharges. The results show that the resultant zeolites own more open pore channels and less strong acid sites compared with a conventional ZSM-5 zeolite and demonstrate superior catalytic activity in n-octene hydroisomerization. Significantly, compared with the traditional synthesis process, our approach can greatly reduce the material and energy consumptions and pollutant discharges while significantly increase the raw material utilization efficiency, endowing itself as an economic, eco-s...
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from natural Aluminosilicate Minerals to hierarchical zsm 5 zeolites a nanoscale depolymerization reorganization approach
Journal of Catalysis, 2014Co-Authors: Pei Yuan, Tiesen Li, Chengzhong Yu, Hsiaotao BiAbstract:In this article, we describe a novel strategy for synthesizing hierarchical ZSM-5 zeolites via the nanoscale depolymerization–reorganization of natural Aluminosilicate Minerals. This strategy involves two important steps: the first is the top-down depolymerization of one aluminum-rich Aluminosilicate Mineral via a novel submolten salt system and one silicon-rich Aluminosilicate Mineral via conventional thermal treatment into nanoscale building blocks, and the second is the bottom-up rearrangement and reorganization of nanoscale building blocks in the synthesis system into hierarchical ZSM-5 zeolites. When used as a fluid catalytic cracking catalyst additive, the resulting ZSM-5 zeolite with hierarchical micro–mesoporous structure exhibited high activity and selectivity for valuable products in preliminary oil refining tests. The salient features of the strategy lie in that it neither involves any inorganic aluminum and silicon salts as precursors nor uses any secondary mesoscale template and post-treatment to create mesopores, thus demonstrating itself to be a green route to synthesizing hierarchical zeolites.
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green synthesis of zeolites from a natural Aluminosilicate Mineral rectorite effects of thermal treatment temperature
Applied Clay Science, 2014Co-Authors: Haiyan Liu, Pei Yuan, Xiaojun Bao, Gang Shi, Tong ShenAbstract:Abstract This article reports the effects of thermal treatment temperature on the physicochemical properties of a rectorite Mineral and the chemical reactivity and crystallization behavior of the activated rectorite products for zeolite synthesis purposes. The raw rectorite Mineral and its thermal activation products were systematically characterized by XRF, XRD, FTIR and 29Si and 27Al MAS NMR techniques and the resultant zeolites were characterized by XRD technique. The results showed that after being thermally treated in the temperature range of 25–1300 °C, the rectorite experienced the following four stages: dehydration at 150–300 °C, dehydroxylation at 600–700 °C, structure collapse at 1000 °C, and new phase formation at above 1100 °C. Moreover, it was found that after being thermally treated at ca. 1000 °C, the SiO4 tetrahedral units in the rectorite Mineral are distorted, while the AlO6 octahedral units are decomposed and thus the maximum contents of active SiO2 and Al2O3 can be simultaneously achieved, and as a result, zeolite P is obtained when using the rectorite calcined at 1000 °C as the starting material for fabricating zeolites. Our results further revealed that like kaolin rectorite after thermal activation at a suitable temperature can be used for zeolite synthesis and thus demonstrates itself a promising feedstock for the green synthesis of zeolites directly from natural Aluminosilicates without experiencing intermediate chemicals.
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From natural Aluminosilicate Minerals to hierarchical ZSM-5 zeolites: A nanoscale depolymerization–reorganization approach
Journal of Catalysis, 2014Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Li Tiesen, Xiaojun BaoAbstract:In this article, we describe a novel strategy for synthesizing hierarchical ZSM-5 zeolites via the nanoscale depolymerization–reorganization of natural Aluminosilicate Minerals. This strategy involves two important steps: the first is the top-down depolymerization of one aluminum-rich Aluminosilicate Mineral via a novel submolten salt system and one silicon-rich Aluminosilicate Mineral via conventional thermal treatment into nanoscale building blocks, and the second is the bottom-up rearrangement and reorganization of nanoscale building blocks in the synthesis system into hierarchical ZSM-5 zeolites. When used as a fluid catalytic cracking catalyst additive, the resulting ZSM-5 zeolite with hierarchical micro–mesoporous structure exhibited high activity and selectivity for valuable products in preliminary oil refining tests. The salient features of the strategy lie in that it neither involves any inorganic aluminum and silicon salts as precursors nor uses any secondary mesoscale template and post-treatment to create mesopores, thus demonstrating itself to be a green route to synthesizing hierarchical zeolites.
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catalytic properties of a hierarchical zeolite synthesized from a natural Aluminosilicate Mineral without the use of a secondary mesoscale template
Chemcatchem, 2013Co-Authors: Jiajia Ding, Haiyan Liu, Pei Yuan, Gang Shi, Xiaojun BaoAbstract:A hierarchical ZSM-5 zeolite with a bimodal meso-microporous system, high crystallinity, and a large surface area and meso-micropore volume was successfully synthesized from a natural layered Aluminosilicate Mineral rectorite without using a secondary mesoscale template. The physicochemical and catalytic properties of the hierarchical ZSM-5 zeolite were extensively characterized. The results showed that the mesopores of the synthesized hierarchical ZSM-5, which are almost slitlike intercrystal pores, originate from the construction of primary nanorods of the ZSM-5 zeolite. Analysis of the crystallization process revealed that the undissolved rectorite debris acted as seed crystals and played a structure-directing role, which is the key factor that influences the formation of the hierarchical structure. Such a hierarchical ZSM-5 zeolite, as a result of its unique structural characteristics and increased accessibility of acid sites, possessed a remarkably enhanced activity for the cracking of 1,3,5-triisopropylbenzene, a dramatically higher anti-deactivation ability for cumene conversion, and a significantly improved propylene-boosting performance for heavy oil cracking than the other catalysts tested.
Yuanyuan Yue - One of the best experts on this subject based on the ideXlab platform.
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controlled synthesis of zsm 5 zeolite with an unusual al distribution in framework from natural Aluminosilicate Mineral
Microporous and Mesoporous Materials, 2020Co-Authors: Yanni Zhou, Haiyan Liu, Xiaojun Bao, Yuanyuan Yue, Xiaorong Rao, Haibo ZhuAbstract:Abstract Precisely tuning the location of Al atoms in zeolite framework that plays a critical role in determining the catalytic performance of zeolite based catalysts has attracted considerable attention. In this article, we present an organotemplate-free approach for the controllable synthesis of ZSM-5 zeolite with a high content of Al pairs selectively located at the channel intersections, which is achieved by using a submolten salt (SMS) depolymerized rectorite as both the Al source and heteropical crystalline seeds. The quasi in-situ characterizations tracking the zeolite crystallization process reveal that the depolymerized rectorite with abundant oligomeric Aluminosilicate species and Al–O-(Si–O)1,2-Al sequences plays dual roles in the synthesis of ZSM-5 zeolite. These oligomeric Aluminosilicate species like 5- and 6-membered ring structures serve as the crystalline seeds to promote the zeolite nucleation; simultaneously, the Al–O-(Si–O)1,2-Al sequences are in-situ transformed into the final zeolite framework leading to the generation of numerous Al pairs selectively located at the channel intersections. Such an unusual Al distribution endows the synthesized ZSM-5 zeolite with excellent catalytic performance in methanol to aromatics (MTA) reaction. Our strategy provides a sustainable and efficient way to design and synthesize high-performance zeolites with special framework Al distributions for catalytic applications.
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Mesoporogen-free synthesis of hierarchical sodalite as a solid base catalyst from sub-molten salt-activated Aluminosilicate
Particuology, 2020Co-Authors: Jinbiao Yang, Xiaojun Bao, Yuanyuan Yue, Haiyan LiuAbstract:Abstract A rapid and environmentally friendly approach to synthesize hierarchical sodalite from natural Aluminosilicate Mineral without the involvement of any mesoporogen or post-synthesis treatment was developed. This strategy involves three important steps: the first is the depolymerization of an Aluminosilicate Mineral into highly reactive silicon and aluminum species with ideal meso-scale structures through activation of a sub-molten salt. The second step is the hydrolysis and condensation of the activated Aluminosilicate Mineral into zeolitic precursors that also have a meso-scale structure. The third is the rapid zeolitization of the zeolitic precursors through the reversed crystal growth route at room temperature and ambient pressure to form hierarchical sodalite. The physicochemical properties of the as-synthesized sodalite were systematically characterized, and the formation mechanism of the hierarchical pore structure was discussed. When used as a solid base catalyst for Knoevenagel condensation, the as-synthesized sodalite and its potassium ion-exchanged product with hierarchical micro–meso–macroporous structure both exhibited high catalytic activity and product selectivity.
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Template-Free Synthesis and Catalytic Applications of Microporous and Hierarchical ZSM-5 Zeolites from Natural Aluminosilicate Minerals
Industrial & Engineering Chemistry Research, 2017Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Yanni Zhou, Zhu Haibo, Zhengshuai Bai, Xiaojun BaoAbstract:Organic templates play a crucial role in zeolite synthesis, but their use causes serious pollutant emissions and increases product costs. Herein, we report a template-free approach to synthesize both microporous and hierarchical ZSM-5 zeolites from natural Aluminosilicate Mineral, which is achieved by (1) utilizing the mother liquid to construct mesopores without using any mesoscale template and (2) reusing the Si-rich alkali liquor and ion-exchanging solution to improve the atom economy without any alkali/acid liquor discharges. The results show that the resultant zeolites own more open pore channels and less strong acid sites compared with a conventional ZSM-5 zeolite and demonstrate superior catalytic activity in n-octene hydroisomerization. Significantly, compared with the traditional synthesis process, our approach can greatly reduce the material and energy consumptions and pollutant discharges while significantly increase the raw material utilization efficiency, endowing itself as an economic, eco-s...
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From natural Aluminosilicate Minerals to hierarchical ZSM-5 zeolites: A nanoscale depolymerization–reorganization approach
Journal of Catalysis, 2014Co-Authors: Yuanyuan Yue, Haiyan Liu, Pei Yuan, Li Tiesen, Xiaojun BaoAbstract:In this article, we describe a novel strategy for synthesizing hierarchical ZSM-5 zeolites via the nanoscale depolymerization–reorganization of natural Aluminosilicate Minerals. This strategy involves two important steps: the first is the top-down depolymerization of one aluminum-rich Aluminosilicate Mineral via a novel submolten salt system and one silicon-rich Aluminosilicate Mineral via conventional thermal treatment into nanoscale building blocks, and the second is the bottom-up rearrangement and reorganization of nanoscale building blocks in the synthesis system into hierarchical ZSM-5 zeolites. When used as a fluid catalytic cracking catalyst additive, the resulting ZSM-5 zeolite with hierarchical micro–mesoporous structure exhibited high activity and selectivity for valuable products in preliminary oil refining tests. The salient features of the strategy lie in that it neither involves any inorganic aluminum and silicon salts as precursors nor uses any secondary mesoscale template and post-treatment to create mesopores, thus demonstrating itself to be a green route to synthesizing hierarchical zeolites.