Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 10
·5556-5562
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IF 7.443
Chunyu Chen,Qinming Wu,Fang Chen,Ling Zhang,Shuxiang Pan,Chaoqun Bian,Xiaoming Zheng,Xiangju Meng,Feng-Shou Xiao
The removal of volatile organic compounds is an important aspect of sustainability and environmental protection. Catalytic oxidation is one of the most efficient routes to achieve this. The K+ form of an aluminium-rich Beta zeolite-supported Pt nanoparticle (2.2 nm) [Pt/KBeta-seed-directed synthesis (SDS)] catalyst is very active for the low-temperature catalytic removal of toluene and results in full conversion at a much lower temperature than a conventional KBeta-supported Pt nanoparticle (Pt/KBeta-TEA) catalyst. The higher activity of the Pt/KBeta-SDS catalyst compared with the Pt/KBeta-TEA catalyst is related to the advantages of the higher K+ content and fewer terminal silanol defects in the KBeta-SDS catalyst than in the KBeta-TEA catalyst. The higher K+ content is helpful for the formation of more Pt0 species, and both the higher K+ content and the lower number of terminal silanol defects are favourable for the adsorption of toluene, as evidenced by XPS and the toluene-TPD profiles. More importantly, the Pt/KBeta-SDS catalyst shows very stable activities in the presence of H2O and CO2 in the feed gases. The combination of this extraordinary activity and excellent stability in the catalytic removal of toluene over the Pt/KBeta-SDS catalyst are important for future environment protection.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2025
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IF 1.6
Xiaoxia Ma,Huijian Guo,Yujia Sui,Yun Li,Jilin Cao
Lactide, a key raw material for polylactic acid, is prone to hydrolysis during synthesis from lactic acid using zeolite beta, reducing yield. To address this issue, zeolite beta with hydrophobic pores was synthesized by template-free method with in situ silicon source modification by tetraethoxyfluorosilane (TEFS). The effect of TEFS addition on the morphology, acidity, and wettability of the synthesized zeolite beta was investigated. The modification with F groups increases the total acid amount and the strength of strong acid sites, especially the Brønsted acid sites; simultaneously, the hydrophobicity of pores was also improved. F group–modified zeolite beta achieved a lactide yield of 84%, significantly higher than the 70% yield of unmodified zeolite beta. This enhancement could be attributed to the increase in Brønsted acid sites and the improvement of the hydrophobic pore microenvironment. This could improve the catalytic reaction activity; additionally, the rapid removal of water from near acid sites could promote the forward movement of the reaction equilibrium and inhibit the hydrolysis of lactide. This work provides a new approach to improve the hydrophobicity of the pores of zeolites as solid acid catalysts, which is beneficial to the efficient production of lactide.
研究领域:
催化化学
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材料科学
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绿色化学
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DOI
高影响因子
Journal of Biobased Materials and Bioenergy
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2017
·Vol. 11
·期 6
·562-567
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IF 0.975
Wang Lan-Ying,Zhuang Jun-Ping,Yu Kai-Rong,Wu Shu-Bin
Sn-Beta zeolite is a promising catalysts for isomerization of glucose to fructose, which is a key step in the conversion of biomass to various platform chemicals. Herein, Sn-Beta-H zeolite was efficiently prepared via hydrothermal synthesis by using Al-Beta. Finally, the product was
heated to 423 K for 48 h then calcined at 550 °C for 6 h to obtain Sn-Beta-H sample. The results of XRD patterns confirmed that the prepared catalyst had both microporous and mesoporous; N2 sorption isotherms showed that the main pore size centered at around 3.5 nm; TD-DTG revealed
that the Sn-Beta-H zeolite had good thermal stability with the peaks on the DTG curves was 283 °C; FTIR and UV-Vis spectra also successfully indicated that tin substitution into the zeolite framework. The effects of various reaction conditions including reaction temperature, reaction time
and the amount of catalyst on glucose conversion and fructose yield and selectivity were investigated. Under optimized operating conditions, 10% glucose solution in 40 ml water, catalyst (4 g), at 120 °C for 2 h, resulting in fructose yield of 30.8% and selectivity of 61.3%. Moreover,
Sn-Beta-H zeolite could be easily recovered and efficiently reused without significant loss in its catalytic activity.
研究领域:
催化化学
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生物质转化
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材料科学
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Qiang Yu,Yonghua Guo,Xiaoxia Wu,Zijun Yang,Hua Wang,Qingfeng Ge,Xinli Zhu
Ketonization reactions provide a feasible approach to remove oxygen and increase carbon chain length for conversion of biomass derived carboxylic acids. However, the reaction suffers from fast catalyst deactivation and low ketone selectivity. In this work, Lewis acidic heteroatom Ti-, Zr-, Ce-, and Sn-Beta zeolites were prepared using a two-step post-synthesis method and applied in vapor phase ketonization of propionic acid at 350 °C. Among these zeolites, Zr-Beta shows both the highest activity and selectivity. Characterizations indicate that Zr prefers the vacant tetrahedral site when the Zr content is < 7%, corresponding to the maximal fraction of vacant sites produced from dealumination of the parent H-Beta with a Si/Al ratio of 19. Extraframework Zr may also form at a Zr content ≥ 7%. The tetrahedrally coordinated framework Zr species (mainly in the structure of open sites) show Lewis acidic characteristic, and their density can be linearly correlated with the ketonization activity, indicating that these sites are active sites for ketonization. In contrast to rapid deactivation of H-Beta, the 7% Zr-Beta is stable for ketonization over 60 h, maintaining a conversion of ∼50% and a 3-pentanone selectivity > 96% at a space time of 2 h. The amount of coke deposition on Zr-Beta is about 1/3 of that on H-Beta, and the structure of Zr-Beta is preserved after 60 h of reaction. The results of this work indicate that Zr-Beta zeolite is a promising catalyst for ketonization with good stability and high selectivity toward ketone.
研究领域:
催化化学
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生物质能
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材料科学
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DOI
高影响因子
CELLULOSE
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2019
·Vol. 26
·期 17
·9135-9147
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IF 3.917
Zhou Shengqiang,Yang Xiaomei,Zhang Yali,Jiang Lingyun,Zhou Lipeng,Lu Tianliang,Su Yunlai
Abstract One-pot conversion of cellulose to valued-added platform chemicals such as alkyl levulinate is a promising and challenging process of biomass utilization due to the insolubility of cellulose in alcohol. In this work, commercial heteropoly acid combined with postsynthesized Sn-Beta zeolite was employed to transform cellulose to methyl levulinate (MLE) in one pot. The synergistic catalysis of the homogeneous strong Brønsted (B) acid and the solid strong Lewis (L) acid can effectively realize the depolymerization of solid cellulose and the subsequent isomerization, dehydration and hydration steps to MLE. 55% and 62% of MLE yields were obtained from α-cellulose and microcrystalline cellulose, respectively, at 160 °C for 10 h. Various carbohydrates besides cellulose can also be efficiently converted to MLE in high yields over the bifunctional catalyst system. The effects of the amount of B acid and L acid, the reaction temperature and time and the amount of cellulose on the production of MLE were investigated in detail. Finally, the reaction pathway of cellulose to MLE was revealed. Recyclability tests indicated that the binary catalyst can be reused without decrease of catalytic activity. Graphic abstract
研究领域:
生物质化学
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催化化学
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DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
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2021
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IF 4.094
Shengqiang Zhou,Lipeng Zhou,Yunlai Su,Xiaomei Yang,Hao He
Sn-Beta zeolite is a promising heterogeneous Lewis acid catalyst. Hydrothermal synthesis of Sn-Beta(TEOS) using tetraethyl orthosilicate (TEOS) as silica source is a classical method. However, the hydrolysis of TEOS generates considerable ethanol, which is unfavorable for scalable production of Sn-Beta. Herein, cheap fumed silica and silica sol were used as Si sources to synthesize Sn-Beta and compared with that synthesized from TEOS . The crystalline phase, morphology, physicochemical properties, and the state of Sn were characterized. It was found that Sn-Beta can be successfully prepared with fumed silica and silica sol as well as TEOS as silica source. Sn was introduced into the framework of these samples. Sn-Beta synthesized from fumed silica (Sn-Beta(FS)) and silica sol (Sn-Beta(Sol)) had similar crystallization behavior and full crystallization time as well as morphology, crystal size with that from TEOS. Sn-Beta(Sol) has less silanols and lowest ratio of open/closed tin site among these samples. It exhibited higher catalytic activity for the conversion of glucose to methyl lactate and lower catalytic activity for the isomerization of glucose as compared with the other two samples. Sn-Beta(FS) showed similar catalytic performance in the studied reactions with Sn-Beta(TEOS).
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
BIOMASS & BIOENERGY
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2023
·
IF 6
Jianbin Huang,Jian Zhang,Shiyao Lu,Yehao Liang,Feng-Shou Xiao
Catalytic conversion of glycerol to 1,2-propanediol is an important issue for sustainable production of fine chemicals and biodiesel . Here it is found that pure silica Beta zeolite supported copper species via hydrothermal treatment (Cu/Si-Beta-HT) are highly efficient for hydrogenolysis of glycerol to 1,2-propanediol, achieving 96.0% conversion and more than 99.9% selectivity after reaction at 240 °C for 3 h. TEM images and N 2 O titration experiments confirm the high dispersion of Cu nanoparticles in the catalyst. In addition, pyridine-adsorption FT-IR spectra and NH 3 -TPD profiles suggest the presence of copper species as Lewis acidic sites in the catalyst. The hydrogenolysis of glycerol to 1,2-propanediol mainly includes the dehydration of glycerol to acetol and hydrogenation of acetol into 1,2-propanediol, which are catalyzed by copper cations and Cu nanoparticles, respectively. In situ FT-IR spectra and kinetic studies suggest that the dehydration rate is slower than the hydrogenation rate, and the dehydration is a key step for the hydrogenolysis of glycerol to 1,2-propanediol.
研究领域:
催化化学
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可再生化学
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材料科学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2017
·
IF 5.951
Jian Zhang,Liang Wang,Guoxiong Wang,Fang Chen,Jie Zhu,Chengtao Wang,Chaoqun Bian,Shuxiang Pan,Feng-Shou Xiao
Enhancing the yield of alkyl lactate from sugars is in great demand but challengeable to accomplish. Here we report a facile but efficient route to make this by employing a hierarchical and Sn-containing Beta zeolite (Sn-Beta-H). The hierarporosity in the Sn-Beta-H facilitates the conversion of sugars into important intermediates for producing alkyl lactate in the competition with undesirable side reactions, thus outperforming the conventional Sn-zeolite catalysts in yielding alkyl lactate from a wide scope of sugars. Particularly, the yield of alkyl lactate could reach as high as 72.1% from sucrose. Importantly, the Sn-Beta-H is stable and can be easily recycled for five times with constant catalytic performances.
研究领域:
化学工程
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催化科学
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可再生资源转化
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Shuo Li,Jiahe Sun,Songcheng Bo,Fangfang Yang,Kaixuan Yang,Ting Su,Hongying Lü,Zhiguo Zhu
Oxidative desulfurization (ODS) is regarded as a viable carbon–neutral way to produce sulfur-free fuels. Mo framework substituted zeolite is considered to be a potential heterogeneous catalyst to achieve this goal. Nonetheless, the hydrothermal synthesis of Mo-containing zeolite remains a challenging task in terms of theses aspects including the difficulty in isomorphous substitution of Si with Mo due to the large ionic radius of Mo (59 pm), the tendency of Mo species to precipitate in the alkaline medium, and the prolonged crystallization time. Herein, Mo-Beta zeolites were synthesized via interzeolite transformation within a short time of 24 h. The crystallization process followed the dissolution–recrystallization mechanism. Various techniques were used to confirm that Mo species was isomorphously substituted into zeolite framework. Mesopore was also created over Mo-Beta zeolite with different Mo contents. This Mo-Beta zeolites were employed as heterogeneous catalysts in oxidative desulfurization, where framework Mo species was found to be the catalytic active sites. The process parameters (catalyst dosage, reaction temperature, and H 2 O 2 amounts), reaction kinetics, and reusability were also investigated. Mo-Beta exhibited remarkably high catalyst-weight-based space–time-yield and active-site-based turnover frequency, surpassing the zeolite catalysts in the literatures. This work paves an avenue to the hydrothermal synthesis of metallosilicate zeolites for catalytic oxidations.
研究领域:
化学工程
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催化材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Zhikang Xu,Yunxing Zhang,Xing Wu,Haibo Zhu
Co-based catalysts are emerging as one of the most promising catalysts for propane dehydrogenation (PDH) due to their abundant availability, environmental friendliness, and efficient activation of the C–H bond. Isolated Co(II) is recognized as the active site for activating the C–H bond in PDH; however, the controllable synthesis of Co catalysts with well-defined isolated Co(II) remains a challenge. In this study, a direct and straightforward route was developed for the synthesis of Co-Beta using a fluorine-assisted hydrothermal crystallization method. The structure of Co-Beta was studied using various characterization tools, including XRD, STEM, H 2 -TPR, UV–vis, XPS, solid-state 29 Si MAS NMR and EXAFS techniques. It was confirmed that the Co species are incorporated into the structure of Beta zeolite, existing as isolated Co(II) sites embedded within the framework of Beta zeolite. The optimized catalyst, 1.0Co-Beta, exhibits excellent performance in PDH, achieving a propane conversion of approximately 50 % and propylene selectivity of around 96 % at 600 °C. This performance surpasses that of previously reported non-noble metal catalysts. This study provides fundamental insights on the design and synthesis of highly dispersed metal oxide catalysts for PDH.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2019
·
IF 4.888
Ling Zhang,Yiwen Jiang,Bing-Bing Chen,Chuan Shi,Yaobin Li,Chunying Wang,Shichao Han,Shuxiang Pan,Liang Wang,Xiangju Meng,Feng-Shou Xiao
There is a critical need for improving catalyst activity for formaldehyde combustion due to the importance of enhancing the quality of indoor air in daily life. However, the current catalysts are either low activity (higher than room temperature) or high loading of noble metals (higher than 1 wt.% Pt). Herein, inspired by the concept of catalyst wettability, we design a siliceous Beta zeolite with more hydrophobic feature than that of aluminosilicate Beta zeolite to support Pt catalyst at very low loading (0.2 wt.%), exhibiting extremely excellent catalytic performance in formaldehyde combustion. The formaldehyde could be completely oxidized to carbon dioxide even at -20 °C. The extraordinary catalytic properties are reasonably attributed to that more hydrophobicity of the siliceous zeolite than that of the aluminosilicate zeolite is favorable for desorption of water product, shifting the oxidation equilibrium from HCOOH (intermediate of oxidation of formaldehyde) to carbon dioxide and water. The strategy of hydrophobic zeolite-supported noble metal catalysts might offer an alternative way to develop highly efficient heterogeneous catalysts for the removal of volatile organic compounds.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Xiaowei Wu,Yuqin Li,Yu Li,Mingyu Peng,Zhengquan Yang,Tian Gui,Xiangshu Chen,Hidetoshi Kita
Highly hydrophilic and durable Beta zeolite membranes with high aluminum (Al) spatial distribution were synthesized on inexpensive α-alumina supports via an organic template-free synthesis gel. In the absence of organic templates, the Al spatial distribution of Beta zeolite membrane crystal was regulated by the synthesis parameters such as the Al 2 O 3 /SiO 2 ratio, alkalinity, H 2 O/SiO 2 ratio and crystallization temperature, and the crystal morphology, Si/Al ratio and dehydration performance of the membrane could be further effectively controlled. Under optimal synthesis conditions, the prepared Beta zeolite membrane had an excellent separation factor of over 22,000 and a high permeation flux of 3.02 kg m −2 h −1 in the case of a 90 wt% n-butanol/water mixture at 75 °C. The high-performance Beta zeolite membrane was applied for continuous dehydration to obtain anhydrous n-butanol (99.9 wt%) from a 90 wt% n-butanol/water mixture. Furthermore, Beta zeolite membranes showed long-term acid stability in pervaporation dehydration of a 90 wt% n-butanol/water mixture with a pH value of approximately 2.0 at 75 °C for 192 h, indicating that these membranes by adjusting Al spatial distribution exhibited excellent hydrophilicity and acid resistance, which had a broad promising prospect of industrial applications for dehydration separation of acid-containing organic solvents.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）