Pub Date : 2025-01-09DOI: 10.1016/j.micromeso.2025.113504
Xueyun Ren , Jilong Wang , Shengbo Jin , Ziwen Niu , Hao Xu , Jin-gang Jiang , Peng Wu
Germanosilicates, renowned for their diverse structure and open porosity, possess superior diffusion properties and promising applicability in heterogeneous catalysis. However, their susceptibility to framework collapse in moist conditions, due to vulnerable Ge-O bond to hydrolysis, presents a significant limitation for practical applications. Thus, enhancing the stability of the germanosilicate framework is essential. Moreover, germanosilicates display significant structural flexibility owing to the instability of their interlayer Ge-enriched double 4-rings (d4r) units. This research outlines the outcomes of UOV germanosilicate subjected to diverse post-synthesis treatments. Notably, under acidic conditions, the synthesized Ge-rich UOV (Si/Ge = 3.2) experienced silicon isomorphous substitution, yielding a high-silica UOV analogue (Si/Ge = 140). In contrast, under neutral and alkaline conditions, the UOV germanosilicate underwent structural reorganization and rearrangement of the constituent units, resulting in interzeolite transformation to ∗MRE-type zeolite. The transformation of UOV germanosilicate in neutral and alkaline environments also provides some supplements for the conditions of mutual transformation between zeolites.
{"title":"Exploring post-treatment-induced transformations of UOV germanosilicate","authors":"Xueyun Ren , Jilong Wang , Shengbo Jin , Ziwen Niu , Hao Xu , Jin-gang Jiang , Peng Wu","doi":"10.1016/j.micromeso.2025.113504","DOIUrl":"10.1016/j.micromeso.2025.113504","url":null,"abstract":"<div><div>Germanosilicates, renowned for their diverse structure and open porosity, possess superior diffusion properties and promising applicability in heterogeneous catalysis. However, their susceptibility to framework collapse in moist conditions, due to vulnerable Ge-O bond to hydrolysis, presents a significant limitation for practical applications. Thus, enhancing the stability of the germanosilicate framework is essential. Moreover, germanosilicates display significant structural flexibility owing to the instability of their interlayer Ge-enriched double 4-rings (<em>d4r</em>) units. This research outlines the outcomes of <strong>UOV</strong> germanosilicate subjected to diverse post-synthesis treatments. Notably, under acidic conditions, the synthesized Ge-rich <strong>UOV</strong> (Si/Ge = 3.2) experienced silicon isomorphous substitution, yielding a high-silica <strong>UOV</strong> analogue (Si/Ge = 140). In contrast, under neutral and alkaline conditions, the <strong>UOV</strong> germanosilicate underwent structural reorganization and rearrangement of the constituent units, resulting in interzeolite transformation to <strong>∗MRE</strong>-type zeolite. The transformation of <strong>UOV</strong> germanosilicate in neutral and alkaline environments also provides some supplements for the conditions of mutual transformation between zeolites.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113504"},"PeriodicalIF":4.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study reports the template-free hydrothermal synthesis of Y zeolites, varying aluminum sources (aluminum powder and sodium aluminate), and water content in the synthesis precursor suspensions (140, 180, and 92 mol). Although all samples were crystallized at 90 °C for 4 h, significant differences in crystal size and phase purity were observed. Zeolite Y synthesized with 140 mol of water and sodium aluminate resulted in crystal sizes of 50–100 nm, while reducing the water content to 92 mol produced smaller crystals (50–80 nm) but introduced a GIS impurity phase. The zeolites were tested for CO2 adsorption, revealing a direct relationship between crystal size and adsorption efficiency. Smaller crystal sizes demonstrated higher CO2 adsorption capacities, with zeolites synthesized from aluminum powder outperforming those from sodium aluminate. This study highlights the critical role of synthesis conditions in tailoring the structure and performance of Y zeolites for CO2 adsorption applications.
{"title":"Effect of aluminum source and water content in the precursor suspensions used for the synthesis of nanosized zeolite Y on CO₂ adsorption capacity","authors":"Chalermpan Keawkumay , Narongrit Sosa , Nattawut Osakoo , Sanchai Prayoonpokarach , Jatuporn Wittayakun , Saran Youngjan , Pawan Boonyoung , Pongtanawat Khemthong , Abdallah Amedlous , Svetlana Mintova","doi":"10.1016/j.micromeso.2025.113491","DOIUrl":"10.1016/j.micromeso.2025.113491","url":null,"abstract":"<div><div>This study reports the template-free hydrothermal synthesis of Y zeolites, varying aluminum sources (aluminum powder and sodium aluminate), and water content in the synthesis precursor suspensions (140, 180, and 92 mol). Although all samples were crystallized at 90 °C for 4 h, significant differences in crystal size and phase purity were observed. Zeolite Y synthesized with 140 mol of water and sodium aluminate resulted in crystal sizes of 50–100 nm, while reducing the water content to 92 mol produced smaller crystals (50–80 nm) but introduced a GIS impurity phase. The zeolites were tested for CO<sub>2</sub> adsorption, revealing a direct relationship between crystal size and adsorption efficiency. Smaller crystal sizes demonstrated higher CO<sub>2</sub> adsorption capacities, with zeolites synthesized from aluminum powder outperforming those from sodium aluminate. This study highlights the critical role of synthesis conditions in tailoring the structure and performance of Y zeolites for CO<sub>2</sub> adsorption applications.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113491"},"PeriodicalIF":4.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.micromeso.2025.113493
Ľuboš Zauška , Paula Pillárová , Dominik Volavka , Eva Kinnertová , Jozef Bednarčík , Jiří Brus , Virginie Hornebecq , Miroslav Almáši
This study investigates the adsorption kinetics of heavy metal ions (Co(II)) and azo dye (Congo red) using surface-modified MIL-101(Fe)-NH2. The material's large surface area and dual pore structure enhance adsorption performance, making it suitable for environmental applications. The MIL-101(Fe)-NH2 material was synthesized and further modified with 2-pyridinecarboxaldehyde to create MIL-101(Fe)-Pyr with the aim of enhancing the adsorption properties. Characterization techniques, including FTIR, TG/DTA, ss-NMR, XPS, N2 adsorption/desorption measurements, and PXRD, confirmed the structural integrity and functionalization of the materials. Kinetic studies revealed that MIL-101(Fe)-Pyr demonstrated superior adsorption capacity and faster kinetics for Co(II) ions compared to pristine MIL-101(Fe)-NH2. The adsorption mechanisms were analyzed using pseudo-first-order, pseudo-second-order, and Elovich models. The pseudo-second-order model provided the best fit for both Co(II) and Congo red adsorption. Boyd's diffusion model indicated that external diffusion is a significant rate-controlling step. The adsorption isotherms were fitted with the Freudlich and Langmuir models, and the thermodynamics of the adsorption processes were also studied. The adsorption mechanism of the selected pollutants was proposed, and the stability and reusability of the materials were investigated. The study concludes that surface modifications enhance the material's adsorption properties, making MIL-101(Fe)-Pyr a promising adsorbent for removing pollutants from aqueous environments.
{"title":"Kinetic adsorption mechanism of cobalt(II) ions and Congo red on pristine and Schiff base-surface-modified MIL-101(Fe)-NH2","authors":"Ľuboš Zauška , Paula Pillárová , Dominik Volavka , Eva Kinnertová , Jozef Bednarčík , Jiří Brus , Virginie Hornebecq , Miroslav Almáši","doi":"10.1016/j.micromeso.2025.113493","DOIUrl":"10.1016/j.micromeso.2025.113493","url":null,"abstract":"<div><div>This study investigates the adsorption kinetics of heavy metal ions (Co(II)) and azo dye (Congo red) using surface-modified MIL-101(Fe)-NH<sub>2</sub>. The material's large surface area and dual pore structure enhance adsorption performance, making it suitable for environmental applications. The MIL-101(Fe)-NH<sub>2</sub> material was synthesized and further modified with 2-pyridinecarboxaldehyde to create MIL-101(Fe)-Pyr with the aim of enhancing the adsorption properties. Characterization techniques, including FTIR, TG/DTA, ss-NMR, XPS, N<sub>2</sub> adsorption/desorption measurements, and PXRD, confirmed the structural integrity and functionalization of the materials. Kinetic studies revealed that MIL-101(Fe)-Pyr demonstrated superior adsorption capacity and faster kinetics for Co(II) ions compared to pristine MIL-101(Fe)-NH<sub>2</sub>. The adsorption mechanisms were analyzed using pseudo-first-order, pseudo-second-order, and Elovich models. The pseudo-second-order model provided the best fit for both Co(II) and Congo red adsorption. Boyd's diffusion model indicated that external diffusion is a significant rate-controlling step. The adsorption isotherms were fitted with the Freudlich and Langmuir models, and the thermodynamics of the adsorption processes were also studied. The adsorption mechanism of the selected pollutants was proposed, and the stability and reusability of the materials were investigated. The study concludes that surface modifications enhance the material's adsorption properties, making MIL-101(Fe)-Pyr a promising adsorbent for removing pollutants from aqueous environments.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113493"},"PeriodicalIF":4.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-08DOI: 10.1016/j.micromeso.2025.113503
Jun Zhao , Zhaopeng Liu , Dehui Wang , Lei Zhao , Diandian Shi , Zhiyu He , Feng Shao , Peng Lu , Valentin Valtchev
The goal of obtaining non-oxidative propane dehydrogenation (PDH) catalysts with low cost and environmental friendliness as alternatives to Pt and Cr-based catalysts, has been pursued for years. Zn-based catalysts have demonstrated great potential in the PDH process, but their activity and stability still need to be improved. Herein, we report a Zn-based zeolite catalyst with atomic Zn active sites that are highly dispersed and confined in a layered-like pure silica zeolite (Silicalite-2), via one-pot hydrothermal synthesis using a ligand-protection method. The atomic dispersion of isolated Zn2+ species and their successful trapping and stabilizing by Si−OH in pure-silica LS-2-150 zeolite are unambiguously corroborated using complementary characterization techniques. In PDH reaction (550 °C, WHSV = 2.4 h−1), the optimized Zn2.65 %@LS-2 exhibits excellent initial activity (the propane conversion at 32.2 % and the propene selectivity at 90.1 %) and good catalytic stability after 6 cycles for 60 h on stream (the deactivation rate of 0.0087 h−1). Thus, this work presents a highly active and more durable Zn-based zeolite catalyst that is promising for PDH applications.
{"title":"Atomically dispersed zinc sites confined in a layered silicalite-2 zeolite with enhanced stability for propane dehydrogenation","authors":"Jun Zhao , Zhaopeng Liu , Dehui Wang , Lei Zhao , Diandian Shi , Zhiyu He , Feng Shao , Peng Lu , Valentin Valtchev","doi":"10.1016/j.micromeso.2025.113503","DOIUrl":"10.1016/j.micromeso.2025.113503","url":null,"abstract":"<div><div>The goal of obtaining non-oxidative propane dehydrogenation (PDH) catalysts with low cost and environmental friendliness as alternatives to Pt and Cr-based catalysts, has been pursued for years. Zn-based catalysts have demonstrated great potential in the PDH process, but their activity and stability still need to be improved. Herein, we report a Zn-based zeolite catalyst with atomic Zn active sites that are highly dispersed and confined in a layered-like pure silica zeolite (Silicalite-2), via one-pot hydrothermal synthesis using a ligand-protection method. The atomic dispersion of isolated Zn<sup>2+</sup> species and their successful trapping and stabilizing by Si−OH in pure-silica LS-2-150 zeolite are unambiguously corroborated using complementary characterization techniques. In PDH reaction (550 °C, WHSV = 2.4 h<sup>−1</sup>), the optimized Zn<sub>2.65 %</sub>@LS-2 exhibits excellent initial activity (the propane conversion at 32.2 % and the propene selectivity at 90.1 %) and good catalytic stability after 6 cycles for 60 h on stream (the deactivation rate of 0.0087 h<sup>−1</sup>). Thus, this work presents a highly active and more durable Zn-based zeolite catalyst that is promising for PDH applications.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113503"},"PeriodicalIF":4.8,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-08DOI: 10.1016/j.micromeso.2025.113502
Magdalena M. Lozinska , Elliott L. Bruce , Veselina M. Georgieva , Elizabeth M. Feverston , Shubhra J. Bhadra , Garret C. Lau , Timothy C. Golden , Erin M. Sorensen , Roger D. Whitley , Ronald I. Smith , Paul A. Wright , William J. Casteel (Jr)
The preparation of pure Ar from air requires removal of O2 from a crude Ar stream produced by cryogenic distillation. Whereas their similar boiling points make further separation by distillation expensive, the difference in their molecular sizes makes separation by flexible zeolites an attractive route to kinetic separation. Modifying the cation content of the flexible and cubic zeolite Rho enables precise tuning of a single window size for unprecedented kinetic separation of O2 from Ar. Li-Rho (unit cell Li9.8Al9.8Si38.2O96) is a very selective adsorbent due to its small pore size, but the highly distorted framework results in very slow O2 diffusion. By replacing some of the Li+ with H+, Cs+, or Zn2+, the window can be enlarged and in some cases the window cation occupancy reduced, increasing O2 diffusion rates whilst retaining high O2/Ar selectivity. The optimum unit cell composition among those examined was found to be Li6.2Zn1.8-Rho (O2/Ar selectivity = 813, D/r2(O2) = 0.37 s−1).
{"title":"Optimizing flexible zeolite Rho for unrivalled argon purification","authors":"Magdalena M. Lozinska , Elliott L. Bruce , Veselina M. Georgieva , Elizabeth M. Feverston , Shubhra J. Bhadra , Garret C. Lau , Timothy C. Golden , Erin M. Sorensen , Roger D. Whitley , Ronald I. Smith , Paul A. Wright , William J. Casteel (Jr)","doi":"10.1016/j.micromeso.2025.113502","DOIUrl":"10.1016/j.micromeso.2025.113502","url":null,"abstract":"<div><div>The preparation of pure Ar from air requires removal of O<sub>2</sub> from a crude Ar stream produced by cryogenic distillation. Whereas their similar boiling points make further separation by distillation expensive, the difference in their molecular sizes makes separation by flexible zeolites an attractive route to kinetic separation. Modifying the cation content of the flexible and cubic zeolite Rho enables precise tuning of a single window size for unprecedented kinetic separation of O<sub>2</sub> from Ar. Li-Rho (unit cell Li<sub>9.8</sub>Al<sub>9.8</sub>Si<sub>38.2</sub>O<sub>96</sub>) is a very selective adsorbent due to its small pore size, but the highly distorted framework results in very slow O<sub>2</sub> diffusion. By replacing some of the Li<sup>+</sup> with H<sup>+</sup>, Cs<sup>+</sup>, or Zn<sup>2+</sup>, the window can be enlarged and in some cases the window cation occupancy reduced, increasing O<sub>2</sub> diffusion rates whilst retaining high O<sub>2</sub>/Ar selectivity. The optimum unit cell composition among those examined was found to be Li<sub>6.2</sub>Zn<sub>1.8</sub>-Rho (O<sub>2</sub>/Ar selectivity = 813, <em>D/r</em><sup><em>2</em></sup>(O<sub>2</sub>) = 0.37 s<sup>−1</sup>).</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"387 ","pages":"Article 113502"},"PeriodicalIF":4.8,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-03DOI: 10.1016/j.micromeso.2024.113486
Huimin Zheng , Jiayue Niu , Yinan Liu , Shenfei Bai , Jing Ji , Shilin Tian , Zheyuan Tang
In gasoline deep desulfurization, the adsorption desulfurization technology encounters challenges due to the strong competitive interactions between aromatic molecules and thiophene compounds. This study investigates the competitive adsorption mechanism of benzene/thiophene mixtures in HY zeolites using molecular simulation at wide temperatures across full-loading spectra. The findings suggest that increasing the adsorption temperature can enhance thiophene selectivity by adjusting the interaction strength between the adsorbate and the zeolite framework. At loadings surpassing 40 molecules/UC, there is a fundamental shift in the competitive adsorption behavior of benzene and thiophene, impacting thiophene selectivity. The transition in competitive adsorption mechanisms is influenced by various factors, including the redistribution of adsorption sites, changes in adsorption energies, and the surface properties and pore structure of the zeolite framework. This research lays the theoretical groundwork for modifying the surface and mesoporous structure of zeolite frameworks to optimize adsorption behavior for improved thiophene selectivity in confined systems.
{"title":"Unlocking selective desulfurization: A molecular simulation dive into thiophene-benzene competition on HY zeolite","authors":"Huimin Zheng , Jiayue Niu , Yinan Liu , Shenfei Bai , Jing Ji , Shilin Tian , Zheyuan Tang","doi":"10.1016/j.micromeso.2024.113486","DOIUrl":"10.1016/j.micromeso.2024.113486","url":null,"abstract":"<div><div>In gasoline deep desulfurization, the adsorption desulfurization technology encounters challenges due to the strong competitive interactions between aromatic molecules and thiophene compounds. This study investigates the competitive adsorption mechanism of benzene/thiophene mixtures in HY zeolites using molecular simulation at wide temperatures across full-loading spectra. The findings suggest that increasing the adsorption temperature can enhance thiophene selectivity by adjusting the interaction strength between the adsorbate and the zeolite framework. At loadings surpassing 40 molecules/UC, there is a fundamental shift in the competitive adsorption behavior of benzene and thiophene, impacting thiophene selectivity. The transition in competitive adsorption mechanisms is influenced by various factors, including the redistribution of adsorption sites, changes in adsorption energies, and the surface properties and pore structure of the zeolite framework. This research lays the theoretical groundwork for modifying the surface and mesoporous structure of zeolite frameworks to optimize adsorption behavior for improved thiophene selectivity in confined systems.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113486"},"PeriodicalIF":4.8,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The regulations for emissions from internal combustion engine vehicles were becoming increasingly stringent, necessitating the development of cost-effective, high-performance purification materials. In this study, a HCs trap of kaolin-based ZSM-5 zeolite encapsulated ultra-low loading of Pt, with dual functions of adsorption and oxidation, was synthesized by a ligand-assisted hydrothermal method (Pt0.1@ZSM-5). The results of the corresponding adsorption-oxidation test demonstrated that the degradation efficiency of Pt0.1@ZSM-5 on propene reached 89.6 %, which could effectively reduce propene emission during cold-start period. More importantly, the degradation efficiency of Pt0.1@ZSM-5 on propene reached 67.9 % at the low temperature stage of 60 °C–160 °C. The primary reason for this was that the Pt0.1@ZSM-5 sample demonstrated exceptional catalytic activity with regard to propene oxidation, exhibiting a T90 of 192 °C. The confinement effect of zeolite resulted in the Pt0.1@ZSM-5 exhibiting a smaller nanoparticle size, an abundance of acidic sites, and a higher ratio of adsorbed oxygen. These properties contributed to the effective deep oxidation of propene. Furthermore, the degradation efficiency of propene was sustained at a high level (around 95 %) throughout the course of five adsorption-oxidation cycle tests. This study presented a novel approach for the functionalization and utilization of kaolin and provides guidance for its application in exhaust emissions during the cold-start period.
{"title":"Kaolin-derived ZSM-5 zeolite encapsulated with ultra-low loading of Pt catalysts for synergetic hydrocarbon adsorption/oxidation application","authors":"Langchuan Tian, Haotian Wang, Qijie Yi, Meijing Chen, Shengwei Tang, Wenxiang Tang","doi":"10.1016/j.micromeso.2025.113489","DOIUrl":"10.1016/j.micromeso.2025.113489","url":null,"abstract":"<div><div>The regulations for emissions from internal combustion engine vehicles were becoming increasingly stringent, necessitating the development of cost-effective, high-performance purification materials. In this study, a HCs trap of kaolin-based ZSM-5 zeolite encapsulated ultra-low loading of Pt, with dual functions of adsorption and oxidation, was synthesized by a ligand-assisted hydrothermal method (Pt<sub>0.1</sub>@ZSM-5). The results of the corresponding adsorption-oxidation test demonstrated that the degradation efficiency of Pt<sub>0.1</sub>@ZSM-5 on propene reached 89.6 %, which could effectively reduce propene emission during cold-start period. More importantly, the degradation efficiency of Pt<sub>0.1</sub>@ZSM-5 on propene reached 67.9 % at the low temperature stage of 60 °C–160 °C. The primary reason for this was that the Pt<sub>0.1</sub>@ZSM-5 sample demonstrated exceptional catalytic activity with regard to propene oxidation, exhibiting a T<sub>90</sub> of 192 °C. The confinement effect of zeolite resulted in the Pt<sub>0.1</sub>@ZSM-5 exhibiting a smaller nanoparticle size, an abundance of acidic sites, and a higher ratio of adsorbed oxygen. These properties contributed to the effective deep oxidation of propene. Furthermore, the degradation efficiency of propene was sustained at a high level (around 95 %) throughout the course of five adsorption-oxidation cycle tests. This study presented a novel approach for the functionalization and utilization of kaolin and provides guidance for its application in exhaust emissions during the cold-start period.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113489"},"PeriodicalIF":4.8,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-03DOI: 10.1016/j.micromeso.2025.113488
Taekyung Ryu , Seung Hyeok Cha , Dong Won Hwang
In this study, we investigated the catalytic properties of the potassium-exchanged form of commercial and organic-free synthesized ZSM-5 zeolites with similar Si/Al and K/Al ratios (10–25 and 0.80–1.00, respectively) for the dehydration of biomass-derived methyl lactate to methyl acrylate under different reaction temperatures (340 and 360 °C) and reactant concentrations (35 and 64 wt%). It was found that organic-free synthesized K-ZSM-5 shows a higher methyl acrylate yield than commercially available K-ZSM-5, regardless of the reaction conditions studied. The comprehensive catalytic and characteristic findings from our study demonstrate that K+ ions, acting as active sites, are uniformly distributed within the 10-ring straight and sinusoidal channels of organic-free synthesized K-ZSM-5. This unique configuration imparts greater catalytic activity relative to commercially available K-ZSM-5 for the dehydration of methyl lactate to methyl acrylate with superior reusability even with identical zeolite topology and similar compositions.
{"title":"Catalytic dehydration of methyl lactate to methyl acrylate over potassium-exchanged organic-free ZSM-5 zeolites","authors":"Taekyung Ryu , Seung Hyeok Cha , Dong Won Hwang","doi":"10.1016/j.micromeso.2025.113488","DOIUrl":"10.1016/j.micromeso.2025.113488","url":null,"abstract":"<div><div>In this study, we investigated the catalytic properties of the potassium-exchanged form of commercial and organic-free synthesized ZSM-5 zeolites with similar Si/Al and K/Al ratios (10–25 and 0.80–1.00, respectively) for the dehydration of biomass-derived methyl lactate to methyl acrylate under different reaction temperatures (340 and 360 °C) and reactant concentrations (35 and 64 wt%). It was found that organic-free synthesized K-ZSM-5 shows a higher methyl acrylate yield than commercially available K-ZSM-5, regardless of the reaction conditions studied. The comprehensive catalytic and characteristic findings from our study demonstrate that K<sup>+</sup> ions, acting as active sites, are uniformly distributed within the 10-ring straight and sinusoidal channels of organic-free synthesized K-ZSM-5. This unique configuration imparts greater catalytic activity relative to commercially available K-ZSM-5 for the dehydration of methyl lactate to methyl acrylate with superior reusability even with identical zeolite topology and similar compositions.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113488"},"PeriodicalIF":4.8,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.micromeso.2024.113467
Alexander J. Hoffman , Mingrou Xie , Rafael Gómez-Bombarelli
Zeolite synthesis frequently relies on organic structure-directing agents (OSDAs), but the process of identifying the best OSDA to synthesize a given zeolite remains difficult. We use previously gathered binding energy data, in additional to the formation energies of the siliceous zeolite frameworks and approximate binding entropies of OSDAs to develop new descriptors to improve predictions based on known OSDA-zeolite pairs in the literature. Our earlier work used templating energy () to rank the most likely OSDA-zeolite pairs to be produced from synthesis. Using literature recall area-under-the-curve (AUC) as a performance metric, we find that computing energies associated with the net transformation that occurs during zeolite synthesis (the sum of the formation energy of the zeolite framework and the OSDA binding energy) provides a modest improvement over when predicting the zeolite phase that a given OSDA produces, from 67.5% average literature recall to 72.3%, but negligibly improves predictions for the best OSDA for a given zeolite framework, from 68.3% to 68.8%. We then use machine learning symbolic regression to develop a new descriptor, which we call , that slightly improves upon for predicting an OSDA for a given framework, with an average literature recall of 71.8%. While zeolite synthesis remains difficult to predict a priori, the approaches used in this work provide one option for improving these predictions.
{"title":"Learning descriptors to predict organic structure-directing agent applicability in zeolite synthesis","authors":"Alexander J. Hoffman , Mingrou Xie , Rafael Gómez-Bombarelli","doi":"10.1016/j.micromeso.2024.113467","DOIUrl":"10.1016/j.micromeso.2024.113467","url":null,"abstract":"<div><div>Zeolite synthesis frequently relies on organic structure-directing agents (OSDAs), but the process of identifying the best OSDA to synthesize a given zeolite remains difficult. We use previously gathered binding energy data, in additional to the formation energies of the siliceous zeolite frameworks and approximate binding entropies of OSDAs to develop new descriptors to improve predictions based on known OSDA-zeolite pairs in the literature. Our earlier work used templating energy (<span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>i</mi><mi>j</mi><mo>,</mo><mi>T</mi></mrow></msub></math></span>) to rank the most likely OSDA-zeolite pairs to be produced from synthesis. Using literature recall area-under-the-curve (AUC) as a performance metric, we find that computing energies associated with the net transformation that occurs during zeolite synthesis (the sum of the formation energy of the zeolite framework and the OSDA binding energy) provides a modest improvement over <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>i</mi><mi>j</mi><mo>,</mo><mi>T</mi></mrow></msub></math></span> when predicting the zeolite phase that a given OSDA produces, from 67.5% average literature recall to 72.3%, but negligibly improves predictions for the best OSDA for a given zeolite framework, from 68.3% to 68.8%. We then use machine learning symbolic regression to develop a new descriptor, which we call <span><math><msub><mrow><mi>α</mi></mrow><mrow><mi>i</mi><mi>j</mi><mo>,</mo><mi>T</mi></mrow></msub></math></span>, that slightly improves upon <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>i</mi><mi>j</mi><mo>,</mo><mi>T</mi></mrow></msub></math></span> for predicting an OSDA for a given framework, with an average literature recall of 71.8%. While zeolite synthesis remains difficult to predict <em>a priori</em>, the approaches used in this work provide one option for improving these predictions.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113467"},"PeriodicalIF":4.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the catalytic properties of novel granulated hierarchical (micro-meso-macroporous) zeolites H-Yh and H-ZSM-5h in the reaction of aniline and bio-1,2-propanediol are investigated. The influence of shape selectivity, textural and acid characteristics of zeolites on their activity and selectivity in the above reaction is shown. For the first time it was established that zeolite H-Yh was the most effective for obtaining 2-methyl-3-n-propyl-1H-indole 1 (yield 52 %), while 3,4-dimethyl-1-phenyl-1H-pyrrole 2 was obtained predominantly over zeolite H-ZSM-5h (yield 54 %). The conditions for compounds 1 and 2 with the maximum yield were determined. Possible pathways of the obtaining products are proposed, with consideration to the type, concentration and strength of acid sites, as well as the structural features of zeolites.
{"title":"Granulated hierarchical zeolites − novel pathways for utilizing bio-1,2-propanediol in the synthesis of practically important N-heterocycles","authors":"A.S. Artem'eva, N.G. Grigoreva, O.S. Travkina, S.V. Bubennov, D.V. Serebrennikov, B.I. Kutepov","doi":"10.1016/j.micromeso.2024.113478","DOIUrl":"10.1016/j.micromeso.2024.113478","url":null,"abstract":"<div><div>In this paper, the catalytic properties of novel granulated hierarchical (micro-meso-macroporous) zeolites H-Y<sub>h</sub> and H-ZSM-5<sub>h</sub> in the reaction of aniline and bio-1,2-propanediol are investigated. The influence of shape selectivity, textural and acid characteristics of zeolites on their activity and selectivity in the above reaction is shown. For the first time it was established that zeolite H-Y<sub>h</sub> was the most effective for obtaining 2-methyl-3-<em>n</em>-propyl-1H-indole <strong>1</strong> (yield 52 %), while 3,4-dimethyl-1-phenyl-1H-pyrrole <strong>2</strong> was obtained predominantly over zeolite H-ZSM-5<sub>h</sub> (yield 54 %). The conditions for compounds <strong>1</strong> and <strong>2</strong> with the maximum yield were determined. Possible pathways of the obtaining products are proposed, with consideration to the type, concentration and strength of acid sites, as well as the structural features of zeolites.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"386 ","pages":"Article 113478"},"PeriodicalIF":4.8,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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