MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Xiaoli Ding,Yongfu Tang,Hongyong Zhao,Qingping Xin,Yuzhong Zhang
Hollow SAPO-34 with an average particle size of ca .370 nm was synthesized by selective etching its precursor under the controlled alkaline condition. Subsequently, freestanding mixed matrix membranes were synthesized by UV-induced in-situ polymerization of the mixture of hollow SAPO-34, the fluorinated monomer , and the trifunctional cross-linker. The structure and the physical characteristic of hollow SAPO-34 and membranes were characterized by scan electron microscope, wide-angle X-ray diffraction, etc. The effect of the hollow SAPO-34 loading amount on the gas permeation-separation performance of mixed matrix membranes was investigated. The results showed that hollowing out SAPO-34 improved the N 2 /CH 4 sorption selectivity and converted the crystals from preferential adsorption of N 2 to preferential adsorption of CH 4 , the incorporation of hollow SAPO-34 into membranes increased the N 2 /CH 4 solubility selectivity and the permeability. The optimal membrane exhibited a 39-fold increase in N 2 permeability from 6.9 × 10 −13 to 2.7 × 10 −11 cm 3 (STP)cm·cm −2 ·s −1 ·Pa −1 at 0.2 MPa and 35 °C without the loss of N 2 /CH 4 permselectivity, which exceeded the 2008 Robeson upper bound.
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
APPLIED CATALYSIS A-GENERAL
·
2013
·
IF 3.41
Qiying Liu,Hualiang Zuo,Tiejun Wang,Longlong Ma,Qi Zhang
Nano-sized SAPO-11s were hydrothermally synthesized with using di-n-propylamine (DPA) as structure-directing agent in mixed n-tetradecanoamine–n-propanol–H 2 O medium and the Ni/SAPO-11 catalysts were prepared by incipient wetness impregnation. The catalysts was characterized by XRD, SEM, BET, H 2 -TPR, NH 3 -TPD and TG techniques and their catalytic performance was tested in hydrodeoxygenation (HDO) of palm oil to hydrocarbon fuels. Surfactant n-tetradecanoamine could mediate the minimum SAPO-11 sizes into 20–50 nm. As comparing to the commercial SAPO-11, the nano-sized SAPO-11s presented significantly enlarged surfaces and mesoporous volumes, which offered sufficient space and strong interactions for dispersing Ni. One-step HDO of palm oil demonstrated that the nano-sized SAPO-1 supported Ni catalysts showed the high yield (80%) of liquid hydrocarbons, high isomerization selectivity (80%) and excellent stability due to that the catalyst presented appropriate acidity, higher Ni dispersity, balance of metal (Ni) and acid (SAPO-11) functionalities and fast diffusion for bulky palm oil and products. These promotion effects observed over the nano-sized SAPO-11 supported Ni catalysts indicated the potential application in biorefinery of vegetable oils to hydrocarbon fuels.
研究领域:
催化化学
·
可再生资源转化
·
能源材料科学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Lei Fan,Yuchao Lyu,Jianye Fu,Yupeng Tian,Furang Li,Wenjing Zhang,Xinmei Liu
The prominent size effects of metal nanoparticles (NPs) are mainly reflected in the change of electronic and geometric properties, which may induce distinct catalytic performance of the catalyst. Herein, Ni/SAPO-11 bifunctional catalysts with controllable sizes of Ni NPs were synthesized to investigate the particle size effects in n-hexane hydroisomerization. The results show that decreasing Ni particle size from 11.7 to 5.3 nm increases the concentration of surface Ni atoms and the proportion of low-coordinated Ni sites (corner, step sites) by 1.7 and 1.5 times, respectively. The low-coordinated surface Ni atoms have rich dangling bonds and high surface energy, resulting in greatly improved H 2 adsorption and activation abilities. Moreover, an increased proportion of low-coordinated Ni sites within the Ni cluster shifts the d-band center upward, further enhancing the adsorption and activation of reactants. The intrinsic catalytic activity (turnover frequency) of 5.3 nm Ni NPs is ca. 2 times as much as that of the 11.7 nm ones. Besides, the smaller Ni NPs enhanced the metal–acid synergy, leading to a higher selectivity to isomers. This work provides deep insights into the metal particle size effects over the bifunctional Ni/SAPO-11 hydroisomerization catalysts and can be extended to various metal supported catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Chuangye Wang,Jintang Xue,Ruixue Sun,Xinrong Song,Xinyi Zhang,Xufeng Lin,Longli Zhang
The purpose of this paper is to report an efficient templating synthesis of hierarchically porous SAPO-11 molecular sieves. Poly(vinyl alcohol) was phosphorylated to get different phosphorus contents, and those designedly modified polymers were employed as mesoporous template in the hydrothermal synthesis of SAPO-11. Consequently, the prepared hierarchical molecular sieves exhibited higher BET areas, regular mesopore structures, and better acidity than their conventional counterpart. The catalysts with SAPO-11s as support had improved catalytic conversion and selectivity in hydroisomerization of n-hexane. The templating mechanism of the designed mesoporogens as well as the effects of their phosphorus content on the properties of hierarchical SAPO-11 molecular sieves were well discussed. This work provides an effective approach to template intracrystal mesopores in hierarchical silicoaluminophosphate molecular sieves.
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
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Senliang Xi,Xiaojun Wang,Kudzaishe Caren Tome,Tonghuan Zhang,Zongying Han,Meng Gao,Shixue Zhou,Hao Yu
The hydrogen storage performances of MgH 2 improved by the addition of Ni and SAPO-34 were studied in detail. The mixture of MgH 2 with Ni and SAPO-34 was a physical reaction as shown by the X-ray diffraction (XRD) results. The SAPO-34 and Ni were uniformly distributed on the surface of MgH 2 . The thermodynamic and kinetic properties of 90MgH 2 /5Ni/5SAPO-34 were investigated by differential scanning calorimetry (DSC) and pressure-composition-isothermal (PCI) methods. The results showed that the dehydrogenation activation energy of 90MgH 2 /5Ni/5SAPO-34 decreased by 64.3 kJ/mol compared with that of MgH 2 . In addition, the relationship between the value of dehydrogenation heat and hydrogen content was also investigated by in-situ calorimetry. The enthalpy value of each sample in the dehydrogenation processes were calculated by in-situ calorimetry measurement. The dehydrogenation enthalpies of as-milled MgH 2 and 90MgH 2 /5Ni/5SAPO-34 were 63.2 kJ/mol H 2 and 53.6 kJ/mol H 2 , respectively. Thus, the co-doping of Ni and SAPO-34 contributed significantly to decrease the thermodynamic stability and improve the hydrogen sorption kinetic properties of MgH 2 .
研究领域:
材料科学
·
氢储能技术
·
物理化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Shiting Jia,Sai Geng,Mingming Han,Zhen Li,Bolin Zhao,Anyang Shi,Wenyu Xue,Jingyi Lao,Hailong Yu,Qiong Wu,Huihui Wang,Shiwei Liu
In the research of gas-phase Beckmann rearrangement reactions, the employment of modified molecular sieve catalysts has garnered significant research attention. However, the prevalent supported molecular sieve catalysts currently face two formidable challenges. First, the loaded catalytic species are susceptible to detachment, compromising the catalyst’s stability over time. Second, there is a pressing need to enhance the catalytic efficiency to cater to the requirements of modern, highly efficient catalytic processes. Employing a unique microenvironmental framework modification technique, this study has successfully synthesized a silicoaluminophosphate molecular sieve in situ boron doping on the AEL structure. The molecular sieve B-SAPO-11 exhibited a high specific surface area (195.71 m2/g) and enlarged micropore volume (0.065 cm3/g), providing abundant reaction sites and enhancing the efficiency of mass transport and diffusion, respectively, thus giving a favorable microenvironment for the reaction. The catalyst B-SAPO-11 showed an excellent catalytic performance in the gas Beckmann rearrangement reaction of cyclohexanone oxime. The reaction achieved a 96.5% conversion rate and 91.6% selectivity of the desired product under a weight hourly space velocity of 6 h–1 and a temperature of 400 °C. DFT calculations show that adding B forms a synergistic effect with Al, and the dual Bronsted acid catalysis reduces the reaction energy barrier (11.43 kJ/mol). This method has the advantages of high yield of the target product, rapid reaction, and easy catalyst recovery; a new idea was designed to prepare catalysts for gas-phase Beckmann rearrangement reactions.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 51
·32146-32154
·
IF 3.108
Chengkai Pang,Yuqun Zhuo,Qiyu Weng
A series of Mn-exchanged SAPO-34 catalysts were synthesized and developed as catalysts for the low temperature selective catalytic reduction (SCR) of NO with ammonia in the presence of excess oxygen. 4Mn/SAPO-34 showed the highest SCR activity in the temperature range of 120–210 °C. The microstructure of zeolite supports, acidity, manganese species and reaction mechanism were investigated in detail by BET, NH3-TPD, UV-Vis, H2-TPR, XPS and in situ DRIFTS. Mn3+ and Mn4+ related species were proved to be the active sites for the SCR reaction. The Eley–Rideal mechanism was proved to be effective on 4Mn/SAPO-34 for the low temperature SCR reaction in which coordinated NH4+ species react with gas-phase NO to form an activated transition state and subsequently decomposed to N2 and H2O.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 8
·3901-3908
·
IF 3.925
Zhiping Chen,Li Liu,Faxiang Shi,Wenwu Zhou,Zhiyuan Yang,Anning Zhou
A series of hierarchical SAPO-11 molecular sieves synthesized by adding mesoporogens with different alkyl chain lengths were prepared. The synthesized hierarchical SAPO-11s were characterized by XRD, SEM, N2 adsorption–desorption, TEM, NH3-TPD and Py-IR. The results showed that the physicochemical properties of the hierarchical SAPO-11s change with the increase of the alkyl chain length, and the hierarchical SAPO-11 molecular sieve synthesized with DTAB has the largest external surface area and pore volume, and the most medium and strong B acid sites. Furthermore, the 1-octene hydroisomerization reaction on Ni catalysts supported on hierarchical SAPO-11 was investigated and the experimental results showed that the alkyl chain length of the mesoporogen has an obvious influence on the hydroisomerization selectivity. The hierarchical Ni/SAPO-11 catalyst synthesized using DTAB has the highest selectivity of C8 isomers and the lowest cracking selectivity. These results indicate that DTAB is the most suitable mesoporogen for the synthesis of hierarchical SAPO-11 molecular sieves for 1-octene hydroisomerization.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2013
·
IF 5.787
Lin Guo,Yu Fan,Xiaojun Bao,Gang Shi,Haiyan Liu
Silicoaluminophosphate (SAPO-11) samples with enhanced acidity were synthesized by two-stage crystallization in the presence of dodecyltrimethylammonium bromide (DoTAB), in which the Si source was added after the aluminophosphate framework was formed. The structure, elemental composition, acidity, Si environment, and n-octane di-branched isomerization of the as-synthesized SAPO-11 with small crystallites were investigated. The results showed that compared with the conventional one-stage crystallization, the two-stage crystallization produced more Si borders in the resulting SAPO-11. Among the SAPO-11 samples synthesized by two-stage crystallization, the SAPO-11 with the optimal DoTAB content (mol(DoTAB)/mol(SiO 2 ) = 0.015) had the most Si( n Al) (0 < n < 4) species with moderate and strong Brønsted acidity. The catalyst based on the small crystallite SAPO-11 containing a greater number of moderate and strong Brønsted acid sites exhibited superior performance for n-octane di-branched isomerization. This two-stage DoTAB-assisted crystallization opens a new route to enhancing the SAPO-11 acidity and can be extended to the other SAPO molecular sieves.
研究领域:
化学工程
·
催化科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2020
·
IF 6.146
Qianqian Guo,Fan Yang,Xiaohui Liu,Mengqing Sun,Yong Guo,Yanqin Wang
Silicoaluminophosphate-34 (SAPO-34) molecular sieves have important applications in the petrochemical industry as a result of their shape selectivity and suitable acidity. In this work, nanoaggregate SAPO-34 with a large external surface area was obtained by dissolving pseudoboehmite and tetraethylorthosilicate in an aqueous solution of tetraethylammonium hydroxide and subsequently adding phosphoric acid . After hydrolysis in an alkaline solution, the aluminum and silicon precursors exist as Al(OH) 4 − and SiO 2 (OH) − , respectively; this is beneficial for rapid nucleation and the formation of nanoaggregates in the following crystallization process. Additionally, to study the effect of the external surface area and pore size on the catalytic performance of different SAPO-34 structures, the alcoholysis of furfuryl alcohol to ethyl levulinate (EL) was chosen as a model reaction. In a comparison with the traditional cube-like SAPO-34, nanoaggregate SAPO-34 generated a higher yield of 74.1% of EL, whereas that with cube-like SAPO-34 was only 19.9%. Moreover, the stability was remarkably enhanced for nanoaggregate SAPO-34. The greater external surface area and larger number of external surface acid sites are helpful in improving the catalytic performance and avoiding coke deposition.
研究领域:
石油化工
·
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2019
·Vol. 128
·期 2
·1065-1077
·
IF 1.428
Yu Qifan,Liu Xuesong,Chen Hongfeng,Liu Shuang,Jiang Peng
The regeneration mechanism of sulfated Cu/SAPO-34 catalysts in reducing atmospheres (5% H 2 /Ar and NH 3 /Ar at 600 °C) was investigated by using a series of characterization methods. Hydrogen regeneration improved the catalysts’ NH 3 -SCR activity from 150 to 550 °C remarkably, while ammonia regeneration exhibited relatively less obvious promotion effect. The TPR of hydrogen and EPR spectra data show that the regeneration process affects the amount and the coordination of the active isolated Cu 2+ species significantly. The desulfation increases the amount of isolated copper ions and improves the catalytic activity of SCR.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2021
·
IF 3.995
Ruizhen Zhang,Jie Wang,Lina Han,Jiancheng Wang,Liangfu Zhao
HZSM-5 molecular sieves are efficient catalysts in the aromatization of light hydrocarbons and the fabrication of HZSM-5-based core–shell composites has become an important strategy to improve their catalytic performance due to the simultaneous modification of the acidity and pore structures in the catalyst. In this paper, HZSM-5/SAPO-5 (CSZP and CSZC) were synthesized via a two-stage crystallization process using PDDA and CTAB as modifiers of HZSM-5, respectively. The structure, acidity, and the weight of carbon deposition of the resulting molecular sieves catalysts were characterized using various methods and their catalytic behavior in isobutane aromatization investigated. The results show that CSZP exhibits a perfect core–shell structure with a uniform and thin shell composed of nano-SAPO-5, while CSZC has an irregular coat configuration with HZSM-5 covered by a rough and thick shell consisting of flaky micro-SAPO-5 crystals. The introduction of SAPO-5 via an in-situ synthesis decreases the Brønsted acidity of the catalysts to different extents and provides a large number of intergranular mesopores due to the stacking of SAPO-5 on the surface of HZSM-5, which is favorable toward improving the BTEX selectivity (benzene, toluene, ethylbenzene, and xylene) and catalytic stability over CSZP and CSZC. Meanwhile, CSZP has more competitive advantages than CSZC in promoting the mass transfer efficiency due to its significantly thinner shell than CSZC, which combined with its moderate acidity and appropriate mesopore structure result in its excellent selectivity and stability during the aromatization of isobutane.
研究领域:
化学工程
·
催化科学
✓ 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）