RSC Advances
·
2014
·Vol. 4
·期 41
·21479-21491
·
IF 3.708
Quanyi Wang,Shutao Xu,Jingrun Chen,Yingxu Wei,Jinzhe Li,Dong Fan,Zhengxi Yu,Yue Qi,Yanli He,Shuliang Xu,Cuiyu Yuan,You Zhou,Jinbang Wang,Mozhi Zhang,Baolian Su,Zhongmin Liu
In this work, two kinds of mesoporous ZSM-5 were synthesized successfully using a hydrothermal methodology by utilizing different soft templates, namely, dimethyl octadecyl [3-(trimethoxysilyl)propyl]ammonium chloride ([(CH3O)3SiC3H6N(CH3)2C18H37]Cl, TPOAC) and hexadecyl trimethyl ammonium bromide (C16H33(CH3)3NBr, CTAB). The obtained mesoporous ZSM-5 samples were compared with conventional ZSM-5, and the effects of different surfactant usages during the synthesis of mesoporous ZSM-5 on the physicochemical and catalytic properties were systematically investigated. Multiple techniques, such as XRD, SEM, N2 adsorption techniques, HP 129Xe NMR, 27Al MAS NMR, 29Si MAS NMR, and 1H MAS NMR, were employed for the characterization. Although the synthesized mesoporous ZSM-5 samples had equal surface areas, they presented different relative crystallinities, morphologies, pore-size distributions, micropore–mesopore interconnectivity, framework atom coordination states and acidities. When using these synthesized ZSM-5 samples as catalysts for methanol conversion, the mesoporous ZSM-5 templated with TPOAC exhibited an extremely long catalyst lifespan compared to conventional ZSM-5, while mesoporous ZSM-5 templated with CTAB showed no advantage in prolonging the catalyst lifetime during the reaction. The differences in the catalytic lifespan and the reduction of coke deposition were correlated to the variation of acidity and porosity with the mesopore generation in the ZSM-5 catalysts by the usage of different structure-directing agents. Compared to the mesopore structure-directing agent, CTAB, with the use of TPOAC as the template and part of the Si source, mesoporous ZSM-5 could be synthesized with good mesopore–micropore interconnectivity, which accounted for the improved catalytic performance in the reaction of methanol conversion.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
NANOTECHNOLOGY
·
2024
·Vol. 35
·期 12
·125601
·
IF 2.9
Xia Pu,Wanling Cai,Huayao Chen,Fujie Yang,Xiaomei Mu
The key step in preparing mesoporous silica is to remove the organic template agent, and the most common method used to achieve this goal is high-temperature calcination. However, this method has many disadvantages, one of which is that it reduces the silanol density on the surface of mesoporous silica, which affects its subsequent modification. Ionic liquids (ILs) are often used as extractants. In this work, the 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) IL is considered, and the effects of its concentration, reaction temperature, and reaction time as well as HCl concentration on the extraction rate and silanol density were investigated using an IL extraction template agent (cetyl trimethyl ammonium bromide (CTAB)). The results show that an IL concentration of 10%, a reaction temperature of 120 °C, a reaction time of 12 h, and an HCl concentration of 1% are the best reaction parameters; with these parameters, the extraction rate and the silanol density were found to be 93.19% and 2.23%, respectively. The silanol density of mesoporous silica treated by calcination is only 0.81%. A higher silanol density provides more reaction sites, so that the modified mesoporous silica treated with the IL can be loaded with more Zn ions.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Micro & Nano Letters
·
2023
·Vol. 19
·期 1
·e12182
·
IF 1.3
Weilin Jia,Suyang Wang,Yingying Deng,Jie Shen,Ping Zhao,Zepeng Wang,Jiaojing Shao,Yuanyu Wang,Qi Sun
A simple and effective method was reported for the rapid synthesis of zeolite X from kaolin by adding a template agent. The results of X-ray diffraction confirm the good crystallinity of the synthesized X-zeolite with lamellar structure. Transmission electron microscopy images clearly demonstrate the lamellar structure of the synthesized X-zeolite. The corresponding selective electron diffraction pattern suggests that the crystal structure of X-type zeolite is octahedral. The co-existence and uniform distribution of Si, Al, O, and Na in the layered structure of the synthesized X-type zeolite are detected by element mapping. In addition, N 2 adsorption–desorption measurement indicates that the specific surface area of the lamellar zeolite X is 153.4625 m 2 g −1 . The micropore surface area is 148.8374 m 2 g −1 , and the micropore volume is 0.073377 m 2 g −1 . After exploring the influence of different temperatures on the adsorption of carbon dioxide, the research shows that two-dimensional zeolite X has the best adsorption capacity for carbon dioxide. The adsorption and separation performance of CO 2 /CH 4 was investigated. The study showed that the adsorption and separation coefficient of two-dimensional zeolite X was the highest.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Hui Wang,Hao Zhu,Yuelan Zhang,Jianglong Pu
A series of CTAB-templated Ni/Ce catalysts were synthesized by adding CTAB during the hydrothermal synthesis of ceria to improve the pore structure of catalysts. Their catalytic performance was evaluated in the steam reforming of acetic acid and the effects of CTAB concentration on the porous structures , reducibilities , morphology, and activity of catalysts were studied. The catalysts were characterized by BET, XRD , H 2 -TPR, XPS , HRTEM , in-situ DRIFTS , DTG , FTIR , and temperature-programmed reaction to elucidate the structure-activity relationship of the catalyst. The results showed that owing to the CTAB assistance, a high surface area of ceria could be achieved, which induced a better Ni dispersion with a smaller Ni size, strengthened the interaction between Ni and CeO 2 , and promoted the reducibility of Ni, obtaining higher activity and lower methane yield than Ni/Ce. Among these prepared samples, Ni/Ce–C6 showed the highest surface area and the best catalytic performance with a hydrogen yield of up to 82.5% even at a low temperature (550 °C). Owing to the stronger Ni-ceria interaction of Ni/Ce–C6, the lattice oxygen in ceria migrates easily to the Ni surface , interacts with the reaction intermediates, and thus improves the CO 2 /CO ratio in the products. Much more CO and CO 2 and less CH 4 were observed over Ni/Ce–C6 during the temperature-programmed reaction, indicating its high activity. In-situ DRFITS characterization demonstrated that the two types of catalysts had similar reaction intermediates but various adsorption and conversion abilities toward the acetic acid. More reaction intermediates were adsorbed at low temperatures and a higher conversion was obtained over Ni/Ce–C6 owing to its better Ni dispersion. The CTAB assistance inhibited the formation of amorphous carbon but facilitated the formation of graphitic carbon at ∼637 °C which did not induce catalyst deactivation .
研究领域:
化学工程
·
催化材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Aihu Feng,Le Mi,Yang Yu,Yunzhen Cao,Yun Yu,Lixin Song
Volatile organic compounds have seriously affected the natural environment and human health, and adsorption is one of the most effective method for controlling VOCs pollution. In this work, the NH 4 HF 2 -etched NaY-s-x zeolites with intracrystalline mesoporosity are obtained via the surfactant-templating process in weak base NH 4 OH solution. The morphology, microstructure, and toluene adsorption property of as-prepared hierarchical Y zeolites are systematically characterized. It is found that the structural and textural properties of NH 4 HF 2 -etched NaY samples are significantly changed by the simple surfactant-templated approach and the large-sized mesopores inside NH 4 HF 2 -etched NaY sample disappear to form the surfactant-templated mesoporosity with a size of ~4 nm. It is demonstrated that the intracrystalline mesoporosity obviously improves the toluene molecular adsorption properties of zeolite samples. Moreover, the mechanism of the surfactant-templating process is elucidated.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2025
·
IF 2.7
Feng Ye,Shuanshi Fan,Yanhong Wang,Xuemei Lang,Yihui Lv,Weibo Chen,Gang Li
The facile synthesis of hierarchical ZSM-5 zeolites without mesoporogens is highly desirable for industrial applications. In this study, hierarchical ZSM-5 zeolites with abundant mesopores and a nearly single-crystalline structure were rapidly synthesized in a mesoporogen-free system. Under conventional heating, the synthesis time was significantly reduced to just 15 min, significantly improving production efficiency. The key to this ultrafast process was the use of a tubular reactor, combined with the strategic selection of silicon and aluminum sources.
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
Materials Research Express
·
2019
·Vol. 6
·期 11
·115540
·
IF 1.449
Yong Liu,Qiong Luo,Hao Lu,Zhao Wang
The factors influencing the hydrothermal synthesis of ZSM-5 have been investigated in detail, such as silicon source, template, pH, reaction temperature, etc The type of template plays a key role. It is difficult to synthesize ZSM-5 without template or using inorganic template under our research conditions. However, the organic template of tetrapropylammonium bromide (TPABr) or n-butylamine (BTA) is beneficial to the synthesis of HZSM-5. The pH range of 10.79–11.14 is favorable for the synthesis of HZSM-5 zeolite. When temperature is greater than or equal to 160 °C, the synthesis of target zeolites is easy. However, if temperature is ≤140 °C, the synthesized product belongs to amorphous solid. Scanning electron microscopy (SEM) shows that the morphology of HZSM-5 crystal is hexagonal columnar. Fourier transform infrared (FTIR) analysis shows the synthesized product has a good ZSM-5 skeleton structure. The synthetic HZSM-5 zeolite has the BET specific surface area of about 387.326 m2 g−1. The adsorption capacities of the synthesized HZSM-5 for phenol, quinoline and indole can reach up to 43.54 mg g−1, 83.10 mg g−1 and 69.51 mg g−1, respectively.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Su Dan Bao,Agula Bao
Previous research has proven that the pore shape and nitrogen group content of adsorbents play essential roles in determining their carbon dioxide (CO2) adsorption performance. In this article, a series of nitrogen-doped porous carbon materials were prepared for CO2 adsorption by varying the proportion of carbon nitride, the pyrolysis temperature, and the activation ratio of KOH, using chitosan as the carbon source, carbon nitride (g-C3N4 and g-C3N5) as self-sacrificing templating agents, and KOH as the activator. Among the prepared materials, T6-850-1 has the highest specific surface area (SBET) of 2336 m2/g, and T6-750-1 has the highest microporous area (Smicro) and CO2 adsorption capacity (1 bar, 298 K) of 1969 m2/g and 3.49 mmol/g, respectively. The thermal decomposition temperature and products of carbon nitride templates were characterized and tested by thermogravimetric infrared gas chromatography-mass spectrometry (TG-IR-GC-MS), and the thermal decomposition mechanisms of the two carbon nitride templates were investigated. We found that the thermal stability of the template directly affects the pore structure of the final sample as well as the type and quantity of nitrogen species.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CATALYSIS
·
2022
·
IF 8.047
Yuan Liang,Shaoxiang Xu,Meihua Zhu,Jiamin Jiang,Jiao Zhang,Goubing Zhou,Na Hu,Xiangshu Chen,Hidetoshi Kita
In the absence of boric acid, the tubular Ti-MWW zeolite membranes are prepared with dual organic template agents and potassium carbonate by secondary hydrothermal synthesis. 12MR cage and 10 MR of the MWW zeolite topology structure is stabilized by TMAdaOH and HMI organic template agents, K + cations is a critical mineralization agent for preparing Ti-MWW zeolite membrane with bi-layer Ti-MWW zeolites layer in this work. Besides, ion-exchange could greatly improve the catalytic performance of the Ti-MWW zeolite membrane for phenol hydroxylation with H 2 O 2 , influences of ammonium salt, ion-exchange time and temperature on the micro-structure and catalytic performance are investigated. The upper network-like Ti-MWW zeolite layer could be dissolved and removed by ion-exchange with 0.5 M (NH 4 ) 2 SO 4 solution at 60 °C for 24 h, and the “lying” Ti-MWW zeolites layer is kept on the mullite support. On the other hand, ion-exchange could promote the transformation of hexacoordinated extra-framework titanium species to tetracoordinated state in the framework, part of K + cations of Ti-MWW zeolites are replaced with NH 4 + cations. Total flux and phenol conversion of the ion-exchanged Ti-MWW zeolite membrane are 14.89 kg·m −2 ·h −1 and 36.49 % for phenol hydroxylation by H 2 O 2 at 50 °C.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2025
·
IF 7.7
Wei Zhang,Jiangnan Xiang,Yuting Wang,Mengxi Ma,Yan Wang,Bo Qin,Weijiong Dai,Binbin Fan,Jiajun Zheng,Ruifeng Li
In this paper, a one-dimensional ten-membered ring microporous molecular sieve ZSM-48 is employed as a model catalyst, with the number and positional distribution of acid sites in ZSM-48 molecular sieve adjusted by regulating the temperature of templating agent exfoliation. XRD, FT-IR, SEM, TG, NH 3 -TPD, N 2 adsorption-desorption, and the zero-length column (ZLC) method are used for characterization and analysis. The decrease in the distribution depth of acid sites within the microporous channels of ZSM-48 will not only significantly affects the hydroisomerization performance of n -dodecane (resulting in a final yield of isododecane of more than 80 %) but also influences the yield ratio of multi-branched and mono-branched isomers. After the conversion is stabilized, the yield ratio of multi-branched to mono-branched isomers for Z-48-350 is 1.4 to 2.1 times higher than that for Z-48-550. Furthermore, acid site distribution depth profoundly influences reactant diffusion, with Z-48-120 exhibiting a 115 % higher effective diffusion constant than Z-48-550 at 140 °C. Shortening the distribution depth of acid sites in the micropores does not significantly change the product distribution of n -dodecane monomethyl isomers but markedly suppresses the cracking reaction due to reduced diffusion limitation of olefinic intermediates. This enables efficient and selective hydroisomerization of long-chain n -alkanes.
研究领域:
催化化学
·
材料科学
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 7
·5359-5365
·
IF 2.993
Guo Bing,Lin Xiuzhen
A novel hierarchically mesoporous–macroporous tin organophosphonate with intra-framework organic groups is successfully fabricated through a facile hydrothermal route with SnCl 4 ·5H 2 O as tin source and diethylene triamine pentakis(methylphosphonic acid) as organophosphorus source in the presence of cetyltrimethylammonium bromide (CTAB) as the templating agent. The as-prepared hybrid had macroporous structures with the pore size in the range of 0.6–2.1 μm and a specific surface area of 170 m 2 /g. Besides, the pore walls had particle-aggregated mesoporous substructures, consisting of amorphous tin organophosphonates, as characterized by SEM, TEM and N 2 adsorption analysis and wide- and low-angle X-ray diffraction. FT-IR and NMR results indicated the integrity of the organophosphonate groups into the hybrid solid. It was found that the surfactant CTAB played an important role in obtaining macropores, and a possible formation route was proposed.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2024
·
IF 10.5
Yuchao Wang,Hongmin Wang,Benjing Li,Peng Han,Guicun Qi,Dali Gao,Zeqi Wei,Shengyang Tao
Monolithic carbon with hierarchically porous structure has a promising prospect for a wide range of applications in the fields of energy, environment, catalysis, etc. Due to the reliance on the utilization of templating agents, conventional preparation approaches often suffer from time-consuming preparation, complex post-processing, and uneconomical cost. Herein, we develop a novel strategy to match the sol-gel transition with the phase separation process for the direct preparation of hierarchically porous carbon monolith (HPCM) without templating agent. Resorcinol and resol are employed as carbon sources to adjust the polymerization for the formation of bi-continuous microstructure. Well-defined hierarchical pores and large specific surface area for fast mass diffusion enable the HPCM to be a prospective kind of electrode material in supercapacitor with an outstanding specific capacitance over 350 F g −1 (1.0 A g −1 ). After facile sulfonation, the modified HPCM can act as solid acid catalyst to realize a high-performance production of 5-hydroxymethylfurfural (5-HMF) in a 90 % yield with turnover frequency (TOF) value up to 155.9 h −1 . Additionally, HPCM also exhibits an excellent Joule heating effect, which can be applied to the thermal management after compounding with phase change materials. The desirable integrated performance enables HPCM to be a valuable material suitable for various applications.
研究领域:
材料科学
·
能源化学
·
催化化学
✓ 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）