Clean Energy
·
2025
·
IF 3.7
Jiang Zhenhua,Xia Wei,Zhang Yanli,Wang Xinrui,Dong Mingyuan,Chen Kun,Liu Dong,Lu Baowang
This study aims to compare the catalytic performance of ZSM-5 and SAPO-34 zeolite catalysts in the conversion of ethanol. Through experiments conducted at different temperatures (773 K and 673 K), it was found that SAPO-34 initially exhibits superior propylene selectivity compared to ZSM-5. However, the propylene yield on SAPO-34 gradually decreases, while the ethylene yield increases with time on stream. density functional theory calculations were employed for the investigation of reaction mechanism. The results indicate that the SAPO-34 catalyst surface favors propylene desorption, which beneficial for its initial high propylene selectivity. Nevertheless, the smaller pore structure of SAPO-34 limits the effective diffusion of products, leading to product accumulation within the pores and potentially causing catalyst coking and deactivation. By combining the experimental results with theoretical calculation, this study not only explored the selectivity difference between SAPO-34 and H-ZSM-5 in ethanol conversion reaction, but also revealed the influence of different molecular sieve catalyst structures on product distribution and catalyst stability.
研究领域:
催化化学
·
材料科学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 9
·6664-6672
·
IF 3.201
Yao-Yi Xu,Xue-Ling Wei,Shuai Liang,Ya-Li Sun,Zi-Sheng Chao
Considering the reliable characteristics and the suitable silica alumina content of kaolin, a new way of synthesizing a ZSM-5/NaA hybrid zeolite membrane on 170 mm length ceramic tubes by employing kaolin as a modification layer using a hydrothermal synthesis process was presented for the first time in this work. Kaolin was filtrated on the surface of the support (not only the ceramic tube, but also the NaA membrane layer) as a modification layer not only promoting the interface interlinkage among the support, NaA membrane and ZSM-5 membrane layer, but also promoting the growth of zeolite membranes. The SEM and XRD results showed that compact and homogeneous NaA and ZSM-5 zeolite layers were both formed with the thicknesses being 7.06 μm and 6.14 μm, respectively, after modification with kaolin. The permeation separation experiments demonstrated that the performance of the ZSM-5/NaA hybrid membrane was better than that of the monolayer zeolite membrane with permselectivities of H2 over CO2, N2, CO and CH4 of 5.40, 4.65, 4.70 and 3.93, respectively, which were higher than the corresponding Knudsen diffusion coefficients. Above all, modifying the support with kaolin and then synthesizing the ZSM-5/NaA hybrid membrane could strengthen the performance of the zeolite membrane effectively, which provided a new approach for the synthesis of high performance zeolite membranes in the field of membrane separation.
研究领域:
材料科学
·
膜分离技术
✓ 已验证
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2013
·
IF 4.75
Huiyan Zhang,Mengmeng Luo,Rui Xiao,Shanshan Shao,Baosheng Jin,Guomin Xiao,Ming Zhao,Junyu Liang
Chemical liquid deposition (CLD) with KH550, TEOS and methyl silicone oil as the modifiers was used to modify ZSM-5 and deposit its external acid sites. The characteristics of modified catalysts were tested by catalytic conversion of biomass pyrolysis-derived compounds. The effects of different modifying conditions (deposited amount, temperature, and time) on the product yields and selectivities were investigated. The results show KH550 modified ZSM-5 (deposited amount of 4%, temperature of 20 °C and time of 6 h) produced the maximum yields of aromatics (24.5%) and olefins (16.5%), which are much higher than that obtained with original ZSM-5 catalyst (18.8% aromatics and 9.8% olefins). The coke yield decreased from 44.1% with original ZSM-5 to 26.7% with KH550 modified ZSM-5. The selectivities of low-molecule-weight hydrocarbons (ethylene and benzene) decreased, while that of higher molecule-weight hydrocarbons (propylene, butylene, toluene, and naphthalene) increased comparing with original ZSM-5.
研究领域:
催化转化
·
能源材料化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Jun-Qing Ye,Pin-Xi Wang,Xin Rong,Qi-Da Ding,Jun-Feng Qian,Sheng-Chun Chen,Ming-Yang He,Qun Chen
Vinylsilane compounds are essential chemical feedstocks and intermediates in organic synthesis. A heterogeneous Cu-containing mesoporous ZSM-5 zeolite catalyst developed through an in-situ doping method can be used for preparing vinylsilane compounds via decarboxylative coupling with remarkable catalytic efficiency. The mesoporous structure along with the appropriate surface area and pore volume of the catalyst is likely to be responsible for facilitating mass transfer in the reaction process. Additionally, due to the suitable Brønsted and Lewis acid active sites, adsorption and activation of reactant molecules can be readily triggered to promote the generation of alkoxyl radicals, which is the crucial species to complete the catalytic cycle. Importantly, the transformation exhibits high efficiency, broad substrate scope, and good reusability for at least six cycles.
研究领域:
有机化学
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2025
·
IF 3.3
Xue-Qing Xu,Shen Yu,Xing-Yu Yue,Zhan Liu,Jia-Min Lyu,Yi-Long Wang,Zhi-Yi Hu,Yu Li,Li-Hua Chen,Bao-Lian Su
Phenol is an important intermediate for high value chemicals. Current phenol production via a three-step cumene process causes severe energy-waste and environmental problems. The conversion of benzene to phenol under mild condition can be achieved by oxidation with Cu-based zeolites. However, conventional microporous zeolite suffers from severe diffusion limitation, especially when bulky molecules are involved, such as benzene. In this work, we used a hierarchically macro-meso-microporous ZSM-5 single crystal (Hier-ZSM-5) as substrate for Cu species (Cu@Hier-ZSM-5). Irregular morphology of opal-like Hier-ZSM-5 exhibits abundant surface Si-OH groups and provides a platform for stabilizing Cu2+ sites. Meanwhile, hierarchical porosity provides significantly improved diffusion ability of bulky molecules. As a result, excellent selective oxidation performance of benzene was obtained with the Cu@Hier-ZSM-5, achieving a conversion of 77% and a phenol selectivity of 73%, which is 1.5 times and 2 times of these obtained with a catalyst based on a microporous ZSM-5, respectively. Species of CuOOH were identified as an important intermediate for benzene oxidation. This hierarchical zeolite system with a synergistic effect of site anchoring and molecular diffusion presents an excellent platform for catalyst design.
研究领域:
催化化学
·
材料科学
·
环境化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2024
·
IF 3.2
Feng Ye,Shuanshi Fan,Xuemei Lang,Yanhong Wang,Yihui Lv,Gang Li
Developing hierarchical zeolites is highly important for catalytic applications. In this study, micro- and submicron-sized hierarchical ZSM-5 zeolites, composed of aggregated nanosized ZSM-5 crystals, were facilely synthesized without any mesoporogen. The effects of the gel composition in a mesoporogen-free system on the formation of ZSM-5 aggregates were studied. The results revealed that the Na 2 O/SiO 2 molar ratio and the aluminum source exerted significant impacts. Furthermore, we demonstrated that the morphology and size of the ZSM-5 aggregate could be easily adjusted by varying the gel composition. Mechanistic insights indicated that the formation of hierarchical ZSM-5 aggregates in the mesoporogen-free system likely followed a space-confined growth mechanism.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
·
2024
·
IF 5.3
Fengya Ran,Meng He,Shiyong Sun,Rui Lv,Sen Lin,Ke Wang,Yevgeny Aleksandrovich Golubev,Olga Borisovna Kotova,Elena Leonidovna Kotova
Zeolite products synthesized from mineral materials are receiving widespread attention, while there are few reports on the introduction of heteroatom metals from minerals into zeolites. Herein, the effects of different silicon sources, hydrothermal reaction time and the amount of template on the crystallisation of Fe-ZSM-5 were investigated. The morphology and structure of ZSM-5 were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), X-ray electron spectroscopy (XPS) and scanning electron microscopy (SEM). The catalysis of 3,3′,5,5′-tetramethylbenzidine (TMB) by Fe-ZSM-5 was then carried out to evaluate its enzyme-like catalytic performance as a type of nanozyme catalyst. The results showed that Fe-ZSM-5 exhibited peroxidase-like activity, oxidizing TMB into a colored substance in the presence of hydrogen peroxide (H 2 O 2 ). Kinetic analysis implied that, compared with natural horseradish peroxidase (HRP), Fe-ZSM-5 peroxidase mimics exhibit inferior affinity and enzymatic catalytic velocity towards the TMB substrate. However, it exhibited excellent stability under extreme pH, temperature, and ionic strength conditions. This work provides a possible reference for the construction of functional nanozymes using natural mineral resources.
研究领域:
材料科学
·
催化化学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2020
·Vol. 26
·期 28
·6147-6157
·
IF 4.857
Zhaoqi Ye,Yang Zhao,Hongbin Zhang,Yahong Zhang,Yi Tang
Graphical Seed-induced synthesis : Basic mesoporous ZSM-5 with adjustable alkaline-earth metal species have been synthesized by an acid co-hydrolysis and seed-induced method. Its mesostructure together with the high dispersity of basic guest species was realized by this non-classical crystallization process. For zeolite catalysts, the regulation of active site and pore structure plays an important role in the enhancement of their catalytic performance. In this work, a one-pot and organic template-free co-regulation route is proposed to straightforwardly synthesize basic mesoporous ZSM-5 zeolites with adjustable alkaline-earth metal species. The synthesis pathway combines two decisive strategies: 1) the seed-induced interface assembly growth method and 2) the acidic co-hydrolysis/condensation of aluminosilicate species and alkaline-earth metal (e.g., Mg, Ca, Sr, or Ba) sources. It is interesting that the mesoporous structure was self-evolved through particle-attached seed-interfacial crystallization without the assistance of any template. Meanwhile, the incorporation of alkaline-earth metals species is homogeneous and highly dispersed in the solid products during the whole crystallization process, and finally generate the superior basicity. Catalysis tests of the as-synthesized samples displayed their novel performance in the typical base reaction of Knoevenagel condensation, even for bulky substrates owing to the enhanced diffusion arising from the meso/microporous network. This finding opens new possibilities for facile, cost-effective, and environmentally friendly synthesis of mesoporous high-silica zeolites with tunable acid/base properties, and deepens our understanding of the particle-attached crystallization.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
·
IF 5.455
Tao Jiang,Fumin Wang,Xubin Zhang,Yi Zhai,Guojun Lv,Yu Shen,Yuzhou Wu
Mesocrystal zeolite with well-defined morphology owns mesoporous channels and single crystal characteristics, which could promote diffusion efficiency, stability and catalytic activity. Thus, we performed the controllable synthesis of ZSM-5 mesocrystal without special additives and complex methods. Selected area electron diffraction (SAED) and fast Fourier transform (FFT) showed diffraction spots regardless of crystallization time, which indicated the well oriented feature of synthesized ZSM-5 zeolites. The crystallization process was further investigated. The oriented particle attachment (OPA) effectively guided the synthesis process of mesocrystals, which followed the nonclassical crystallization mechanism. The crystallinity curve exhibited valley-like shape, which manifested that the crystallization pathway went through three stages: fast precipitation, deconstruction and reorganization. The plausible formation mechanism was proposed, which might be useful for the fabrication of ZSM-5 mesocrystal. The prepared zeolites showed superior catalytic performance in aldol condensation reaction between benzaldehyde and 2-hydroxyacetophenone, obtaining 93% of the conversion.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Jing Li,Suxia Ma,Nuo Xu
The pursuit of carbon peaking and carbon neutrality goals necessitates flexible operation and deep peaking of coal-fired units, thus placing heightened demands on nitrogen oxide (NO X ) emission control. Fly ash, a solid waste rich in silicon (Si) and aluminum (Al), should be fully leveraged, and the high-value synthesis of zeolite represents a viable utilization method. In this context, fly ash-based zeolite was prepared as a catalyst to facilitate the generation of active oxides from H 2 O 2 , combined with alkali solution absorption, to achieve efficient denitrification. This approach effectively transforms ‘waste to pollution’ mitigation. The optimal synthesis conditions for FA-ZSM-5 zeolite were established using the alkali fusion hydrothermal synthesis method, with fly ash as the raw material. The specified conditions were NaOH/FA = 1.2, SiO 2 /Al 2 O 3 = 40, H 2 O/Al 2 O 3 = 1325, TPAOH/Al 2 O 3 = 10, ZSM-5-seed addition of 5 %, and a hydrothermal temperature and time of 140 °C for 24 h. Experimental parameters were meticulously investigated to ascertain their impact on nitric oxide (NO) removal efficiency. The highest removal efficiency was achieved under specific conditions: a reaction temperature of 140 °C, an H 2 O 2 concentration of 6 %, a catalyst dose of 0.3 g, an NO concentration of 600 mg/m 3 , and an SO 2 concentration of 1000 mg/m 3 . Finally, analysis of the catalytic oxidation mechanism revealed that H 2 O 2 , when catalyzed by FA-ZSM-5 zeolite, generates ·OH radicals with strong oxidizing properties, thereby facilitating the oxidative removal of NO.
研究领域:
环境科学
·
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2014
·Vol. 16
·期 5
·2580-2586
·
IF 6.852
Anqing Zheng,Zengli Zhao,Sheng Chang,Zhen Huang,Kun Zhao,Hongxiang Wu,Xiaobo Wang,Fang He,Haibin Li
We firstly propose the coupling conversion of bio-derived furans and methanol over ZSM-5 for enhancing aromatic production. The coupling conversion of bio-derived furans and methanol was conducted in a continuous fixed bed reactor. 2-Methylfuran (MF) was used as a probe molecule to identify the possible reaction pathways. The effects of the methanol to MF molar ratio, reaction temperature and weight hourly space velocity (WHSV) on the product distribution from the coupling conversion of MF and methanol were investigated. The experimental results showed that the aromatic yield from the coupling conversion of MF and methanol is about 5.2 times higher than that of the catalytic fast pyrolysis of only MF. In addition, it can also enhance the yield of olefins, the selectivity of xylenes and reduce coke formation. These results indicate that there is a significant synergistic effect between MF and methanol. The synergistic effect could be attributed to the methanol-to-olefins reactions, the Diels–Alder reactions of furans with olefins, and the alkylation reaction of benzene/toluene with methanol occurring during the coupling conversion of MF and methanol. The reaction conditions for maximizing the synergistic effect were a methanol to MF molar ratio of 2 at 550 °C. Moreover, the comparative study of the coupling conversion of different bio-derived furans (MF, 2,5-dimethylfuran (DMF), furfural (FF) and furfuryl alcohol (FA)) and methanol were also considered in this study. The coupling conversion of DMF and methanol exhibited maximum yields of aromatics, olefins and a minimum yield of coke, suggesting that DMF is the best candidate of bio-derived furans for aromatic production in the coupling conversion of bio-derived furans and methanol.
研究领域:
能源化学
·
催化反应工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2024
·
IF 2.8
Haoyu Liu,Jingye Ma,Hong Yuan,Xiang Shi
BACKGROUND A series of Pt@NZSM–5 and Pt/NZSM–5 nanosheets having different Si/Al ratios were prepared via an in situ synthesis and impregnation method, respectively, using C 22 H 45 –N + (CH 3 ) 2 –C 6 H 12 –N + (CH 3 ) 2 –C 6 H 13 (C 22–6–6 ) as the template agent. The oleic acid decarboxylation reaction was carried out using these materials under CO 2 atmosphere and the oleic acid cracking mechanism was inferred from the product distribution of the C8-C17 alkanes. RESULTS The Pt@NZSM–5 and Pt/NZSM–5 was found to comprise thinner nanosheets and exhibited strong metal–substrate interactions. Pt@NZSM–5 nanosheets with a Si/Al molar ratio of 100 had thicknesses of only 8–9 nm along with a mesopore/micropore capacity ratio of 2.7, an acid content of 11 cm 3 /g STP and a high Pt 0 /PtO x ratio. CONCLUSION The Pt@NZSM-5 and Pt/NZSM-5 nanosheets had an interconnected hierarchical system and a large number of metal active sites that facilitated the decarboxylation of oleic acid. The Pt@NZSM–5 nanosheets demonstrated excellent catalytic activity during the cracking of oleic acid under a CO 2 atmosphere, giving a yield of C8–C17 alkanes as high as 83.8% after 5 h at 320 °C. These Pt@NZSM–5 nanosheets also showed greater stability than the Pt/NZSM–5 specimens. © 2024 Society of Chemical Industry (SCI).
研究领域:
催化化学
·
能源材料科学
✓ 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）