CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Xiaolong Liu,Jiahe Sun,Shuo Li,Kaixuan Yang,Ting Su,Hongying Lü,Zhiguo Zhu
Sn-containing zeolite catalysts exhibit the unique feature of selectively activating carbonyl groups in organic compounds, which demonstrate relatively high activity and selectivity in the Baeyer-Villiger (B V) oxidation of aldehydes or ketones using H 2 O 2 as the oxidant. However, the influence of diffusion property and trace water on the ε-caprolactone selectivity as targeted product in the cyclohexanone's B V oxidation system with the green oxidant of aqueous H 2 O 2 remains unclear. To address this, three kinds of Sn-Beta zeolites are prepared by interzeolite transformation, structural reconstruction, and post-synthesis method to establish structure-property relationships. The physicochemical property and Sn coordinated state are investigated in detail. The existence of trace water in the reaction system negatively affects the conversion and product selectivity by competitive adsorption of water with reaction substrates and facilitated hydrolysis of ε-caprolactone, respectively. DFT calculation implies that kinetics dominates the conversion of cyclohexanone → ε-caprolactone → 6-hydroxycaproic acid. The structure-property relationship indicates that the cyclohexanone conversion and ε-caprolactone selectivity are closely related to the adsorption amounts of substrates and the diffusion performance of products, respectively, over Sn-Beta zeolite catalysts. Finally, the reusability and deactivation mechanism are analyzed. This study aims to provide guidance for designing efficient stannosilicate zeolite catalysts for B V oxidation through precisely modulating the zeolite's diffusion property.
研究领域:
催化化学
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材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
·
2018
·
IF 3.566
Jiuling Wang,Yiwei Yang,Miaorong Yu,Guoqing Hu,Yong Gan,Huajian Gao,Xinghua Shi
It is known that rod-like nanoparticles (NPs) can achieve higher diffusivity than their spherical counterparts in biological porous media such as mucus and tumor interstitial matrix, but the underlying mechanisms still remain elusive. Here, we present a joint experimental and theoretical study to show that the aspect ratio (AR) of NPs and their adhesive interactions with the host medium play key roles in such anomalous diffusion behaviors of nanorods. In an adhesive polymer solution/gel (e.g., mucus), hopping diffusion enables nanorods to achieve higher diffusivity than spherical NPs with diameters equal to the minor axis of the rods, and there exists an optimal AR that leads to maximum diffusivity. In contrast, the diffusivity of nanorods decreases monotonically with increasing AR in a non-adhesive polymer solution/gel (e.g., hydroxyethyl cellulose, HEC). Our theoretical model, which captures all the experimental observations, generalizes the so-called obstruction-scaling model by incorporating the effects of the NPs/matrix interaction via the mean first passage time (MFPT) theory. This work reveals the physical origin of the anomalous diffusion behaviors of rod-like NPs in biological gels and may provide guidelines for a range of applications that involve NPs diffusion in complex porous media.
研究领域:
生物物理学
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材料科学
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医学工程
✓ 已验证
产品关联
DOI
高影响因子
Nano Energy
·
2016
·
IF 11.553
Tianqi Li,Majid Beidaghi,Xu Xiao,Liang Huang,Zhimi Hu,Wanmei Sun,Xun Chen,Yury Gogotsi,Jun Zhou
Orthorhombic molybdenum trioxide (α-MoO 3 ) is a layered oxide with promising performance as electrode material for Li-ion capacitors. In this study, we show that expansion of the interlayer spacing (by ~0.32 Å) of the structure along the b-axis, introduced by partial reduction of α-MoO 3 and formation of MoO 3−x (x=0.06–0.43), results in enhanced diffusion of Li ions. Binder-free hybrid electrodes made of MoO 3−x nanobelts and carbon nanotubes show excellent electrical conductivity . The combination of increased interlayer spacing and enhanced electron transport leads to high gravimetric and volumetric capacitances of about 420 F/g or F/cm 3 and excellent cycle life of binder-free MoO 3−x electrodes.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Wei Zhang,Yuting Wang,Jiangnan Xiang,Haiying Lu,Wenrui Jin,Yan Wang,Bo Qin,Weijiong Dai,Binbin Fan,Jiajun Zheng,Ruifeng Li
In this paper, a nanoparticle-stacked ZSM-48 molecular sieve is prepared by modifying the gel preparation process through stepwise crystallization. The corresponding bifunctional catalyst is developed for the hydroisomerization reaction of n -dodecane. The physicochemical properties of ZSM-48 are characterized and analyzed using XRD, SEM, NH 3 -TPD, N 2 adsorption–desorption and zero-length column (ZLC) method. The crystal size of Z-48-T2 synthesized via the stepwise synthesis method is reduced to as small as 0.6 μm, and its acidity is lower compared to that of Z-48-C. Meanwhile, Z-48-T2 exhibits the highest HF value and demonstrates excellent diffusion properties. Consequently, the Z-48-T2 catalyst shows superior catalytic activity and isomerization selectivity, achieving the highest iso -C 12 yield of 83.8 %. The outstanding diffusion performance of Z-48-T2 results in a monomethyl isomerization yield approximately 21 % higher than that of conventional ZSM-48 molecular sieves. Despite these improvements, the final mono-branched isomer product distribution remains unchanged, with 5-methylundecane being the predominant mono-branched isomer for both Z-48-T2 and Z-48-C.
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
FUEL
·
2022
·
IF 8.035
Linjie Guan,Chengming Huang,Dingmei Han,Binbin He,Linhua Zhu,Dedong He,Yi Mei,Yun Zu
A series of HZSM-5 zeolites are fabricated to make it cross-link with an external ultrathin siliceous layer by chemical liquid deposition and the corresponding thickness is measured by TEM and XPS analysis. In situ FTIR experiments disclose that the external surface acidic sites of HZSM-5 zeolite can be covered even by siliceous monolayer (0.7 ∼ 1.3 nm, HZ5-S1). In comparison to parent HZSM-5, the catalytic cracking performance of n-butane over the modified zeolites are evidently enhanced. In particular, the n-butane conversion rate per Brønsted acid site over the HZ5-S2 (16.02 min −1 ) at 550 °C is 2.82 times than that over the HZSM-5 (5.68 min −1 ). Meanwhile, the diffusion properties of n-butane over the zeolites are quantified by in situ FTIR spectroscopic analysis. Negative correlation between steady-state diffusivity and n-butane conversion rate per Brønsted acid site can be found, which unravels the origin of the progressive decrease in the catalytic stability. Under comparable conditions, more advantages can be greatly achieved by HZ5-S1 catalyst in the catalytic activity and the yields to light olefins due to the benign diffusivity and the elimination of external surface acidic sites. This study can provide a guidance for the understanding of diffusion intensification and the rational design of superior catalyst for the catalytic cracking reactions of alkanes.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Zhuyuan Wang,Songmiao Liang,Yan Jin,Lianrui Zhao,Lijie Hu
Optimizing thickness and structure of polyamide (PA) selective layer of thin film composite (TFC) membranes is critical to improve the performance of the membranes. Here, we employed controlled interfacial polymerization to fabricate free-standing PA nanofilms on a thermal-reversible agarose hydrogel. Manipulation of the nanofilms structure was approached by tailoring the amine diffusivity in organic phase composed of benzene and n-hexane mixtures. An UV–vis method was firstly developed to in-situ monitor the diffusion process of amines from aqueous phase to organic phase. The structure and properties of the nanofilms were systematically analyzed by SEM, AFM and ATR-IR. Experimental results revealed that the diffusion kinetics of amines in organic phase is strongly depends on the content of benzene in the mixture solvent and therefore give rise to different thickness and structure of the nanofilms. The amines diffusion rate was accelerated at higher benzene content, causing a rougher surface, thicker thickness and smaller Young's modulus of the resultant nanofilms. Remarkably, with good fitting coefficient of R 2 = 0.9936, the thickness of the nanofilms exhibits a linear relationship with their surface roughness .
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
DYES AND PIGMENTS
·
2022
·
IF 5.122
Yuewei Zhang,Xuchao Jin,Weiran Zhang,Chang Gu,Xuesong Liu,Yu-Mo Zhang
A bistable electrochromic device based on poly(viologen)s is demonstrated with good overall performance, including bistability (4981 s), switch-on voltage (−1.0 V) and reversibility (≥1000 cycles). Overall, these results imply that the control of the diffusivity of viologens is an effective methodology for achieving excellent bistability and low energy consumption.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Xuhong Liu,Shouying Huang,Yunduo Liu,Hu Liu,Xiaomin Zhang,Jing Lv,Ji Qi,Yue Wang,Shiwei Wang,Xinbin Ma
The carbonylation of dimethyl ether (DME) to produce methyl acetate (MA) has a promising prospect in industry. FER zeolites have high MA selectivity and considerable stability but suffer from low activity due to diffusion limitation. Enhancing the diffusion properties of FER zeolites can improve their competitiveness in the DME carbonylation . This study proposed the synthesis of finned FER zeolites with low Si/Al ratio by a secondary growth method. Based on NH 3 -TPD and FTIR, the amount and distribution of acid sites in FER with fins were determined. Combining the normalized MA formation rates on the BASs in 8-MR and diffusion kinetic studies of DME, the influence of diffusion limitation was quantitatively discussed. The results showed that the acidity and diffusion properties were significantly improved on the finned FER, which boosted the DME conversion. This work illustrated the importance of the acidity and diffusion properties in FER catalyzed DME carbonylation. It inspires the rational design of zeolite catalysts by constructing morphology and optimizing compositions.
研究领域:
催化化学
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材料科学
·
工业化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2019
·Vol. 25
·期 34
·8085-8091
·
IF 5.16
Shenyu Yang,Weiwei Xu,Mei Tu,Lingxiang Jiang
Graphical That'll fix it ! The design principles of diffusive adhesives that can bind hydrogels and biological tissues effectively and controllably is described. This approach features the extensive diffusion of adhesive monomers into the substrates and subsequent formation of a bridging network that interpenetrates the substrate networks (see figure). As a proof of concept, we prepared two diffusive adhesives that can bind hydrogels and tissues with exceptional strength and toughness. It is notoriously difficult to adhere water-rich materials, such as hydrogels and biological tissues. Existing adhesives usually suffer from weak and nonadjustable adhesion strength, in part because the contact between the adhesive and substrate is largely restrained to the adhesive/substrate interface. In this study, we have attempted to overcome this shortcoming by developing a class of diffusive adhesives (DAs) that can extend adhesion deep into the substrate to maximize the adhesive/substrate contact. The DAs consist of hydrogel matrices and preloaded water-soluble monomers and crosslinkers that can diffuse extensively into the water-rich substrates after adhesive/substrate contact. Polymerization and crosslinking of the monomers are then triggered leading to a bridging network that interpenetrates the DA and substrate skeletons and topologically binds them together. This kind of adhesion, in the absence of adhesive/substrate covalent bonding, is of high strength and toughness, comparable to those of the best-performing natural and artificial adhesives. More importantly, we can precisely tune the adhesion strength on demand by manipulating the diffusion profile. It is envisioned that the DA family could be extended to include a large pool of hydrogel matrices and monomers, and that they could be particularly useful in biological and medical applications.
研究领域:
材料科学
·
生物医学工程
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
AIP Advances
·
2024
·Vol. 14
·期 3
·
IF 1.4
Cao Shenyang,Dong Tienan,Cao Yichen,Lei Jiabao,Zhang Siyi,Hang Zusheng,Huang Yu’an
The development and characterization of sulfonated melamine formaldehyde resin microspheres (SMF microspheres) as light diffusers in epoxy resin was presented in this paper. The SMF microspheres were prepared through dispersion polymerization with uniform particle size, smooth surface, and a high refractive index. The particle size of the microspheres was controllable within the range from 0.8 to 3.7 µ m according to the pH during acidic condensation and the amount of melamine. Compared to traditional MF microspheres, SMF microspheres possessed unique sulfonic acid groups, higher primary amine content, and stronger polarity, which prevent agglomeration when mixed with epoxy resin. The SMF microspheres thus prepared were used as light-diffusing fillers with epoxy resin as matrix. Experimental results and single-particle Mie scattering simulations confirmed that SMF microspheres with a higher refractive index and smaller particle size exhibited higher light-shading efficiency and the haze of EP, demonstrating their outstanding light-diffusing performance. In summary, the significant potential application of SMF microspheres in the field of light diffusers was demonstrated.
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
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
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 21
·12806-12817
·
IF 2.599
Zhong Xi,Zhou Yuming,He Man,Tong Yuan,Fan Lidan,Cai Zhilan
In this study, a simple, convenient and green approach for the preparation of organosiloxane-coated SiO 2 /CeO 2 (SiO 2 /CeO 2 /poly(VTMS)) with multilayered hierarchical structure is demonstrated by consecutive surface cerium deposition and organosiloxane grafting on the bare silica spheres. The results of the UV–Vis spectrum and photoluminescence analysis suggest that the fillers may be potentially applied in UV absorbers and bioimaging materials. Moreover, the optical diffusers based on the multilayered spheres can be prepared via a solvent-free UV curing process and exhibit enhanced properties like suitable light transmittance, good diffusion capacity and low-incident angle dependence, which are critical for the optical diffusers. In addition, when the concentration of the fillers was 15 wt%, the optical diffusers presented superior light-diffusing properties among all the as-prepared samples. Thus, the films based on the SiO 2 /CeO 2 /poly(VTMS) with multilayered hierarchical structure may open up new possibilities in applications as multifunctional light diffusion films in liquid crystal displays.
研究领域:
材料科学
·
光学工程
✓ 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）