APPLIED CLAY SCIENCE
·
2021
·
IF 5.467
Xinyu Li,Shunyu Han,Dongdong Guan,Nanzhe Jiang,Jingzhe Xu,Sang-Eon Park
The direct synthesis of H-ZSM-5 catalysts from natural aluminosilicate clays is important for the conversion of raw clay resources to high-value-added products. Herein, the solid-like-state conversion was used to directly prepare nano-H-ZSM-5 with uniform morphology and particle size (~300 nm) from leached illite (ISR) as both Si and Al source. Crystallization kinetics indicated that the reactivity of ISR is similar to that of commercially fabricated products and ISR could be rapidly (within 5 h) converted into nano-H-ZSM-5, the crystallinity , morphology, and crystal size of which were strongly affected by the amount of tetrapropylammonium hydroxide (TPAOH). Additionally, the residual Al of ISR uniformly intruded the H-ZSM-5 framework to provide active sites for the methanol-to-aromatics reaction. The catalytic performance stability and BTX selectivity of nano-H-ZSM-5 for this reaction surpassed those of a commercial ZSM-5 catalyst because of the synergistic effect among the specific surface area and volume of micropores , uniform morphology and particle size, and homogeneously distributed acidic sites. This rapid, efficient, and cleaner synthesis reported herein was shown to have no necessity of ion exchange with ammonium salts, to be H-form of ZSM-5 as well as improve the productivity of HZSM-5 catalysts. And consequently, it is expected to reduce the cost of synthesis and provide an opportunity for the comprehensive development and utilization of illite clay resources.
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
Nanomaterials
·
2025
·Vol. 15
·期 5
·401
·
IF 4.3
Xiaoxiao Peng,Haiyan Jing,Lan Yu,Zongdeng Wu,Can Su,Ziyu Ji,Junjie Shu,Hua Tang,Mingzhu Xia,Xifeng Xia,Wu Lei,Qingli Hao
To significantly improve the tribological performance of epoxy resin (EP), a novel h-BN/MoS2composite was successfully synthesized using spherical MoS2particles with lamellar self-assembly generated through the calcination method, followed by utilizing the “bridging effect” of a silane coupling agent to achieve a uniform and vertically oriented decoration of hexagonal boron nitride (h-BN) nanosheets on the MoS2surface. The chemical composition and microstructure of the h-BN/MoS2composite were systematically investigated. Furthermore, the enhancement effect of composites with various contents on the frictional properties of epoxy coatings was studied, and the mechanism was elucidated. The results demonstrate that the uniform decoration of h-BN enhances the chemical stability of MoS2in friction tests, and the MoS2prevents oxidation and maintains its self-lubricating properties. Consequently, due to the protective effect of h-BN and the synergistic interaction between h-BN and MoS2, the 5 wt % h-BN/MoS2composite exhibited the best friction and wear resistance when incorporated into EP. Compared to pure EP coatings, its average friction coefficient and specific wear rate (0.026 and 1.5 × 10−6mm3N−1m−1, respectively) were significantly reduced. Specifically, the average friction coefficient decreased by 88% and the specific wear rate decreased by 99%, highlighting the superior performance of the h-BN/MoS2-enhanced epoxy composite coating.
研究领域:
材料科学
·
摩擦学
·
表面工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Tingwei Zhang,Yijuan Lu,Wenzhi Li,Mingxue Su,Tao Yang,Ajibola Ogunbiyi,Yongcan Jin
In order to efficiently produce γ-valerolactone (GVL) from furfural , a Zr-graphitic carbon nitride/H-β composite (Zr CN/H-β) had been simply prepared via an impregnation-calcination protocol. The morphology and structure, elemental information, and total acid and base properties of the Zr CN/H-β and related catalysts (H-β, CN/H-β, and Zr/H-β) were determined by SEM, TEM , X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD-NH 3 , CO 2 ) characterizations. The effects of reaction temperature and time, and the furfural dosage on GVL production as well as the recyclability of Zr CN/H-β were investigated. With a catalyst/furfural dosage of 0.1/0.22 g, the Zr CN/H-β produced a remarkable 76.5% of GVL yield at 160 °C in 18 h using isopropanol as the solvent. The results of NH 3 , CO 2 -TPD experiments indicated that the simultaneous introduction of Zr species and carbon nitride onto H-β formed new types of acid and base, which should be responsible for the high efficient conversion of furfural to GVL. Additionally, the recyclability of Zr CN/H-β was reasonable.
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
ADVANCED SYNTHESIS & CATALYSIS
·
2016
·Vol. 358
·期 17
·2759-2766
·
IF 6.453
Zhigang Lv,Jing Liu,Wei Wei,Jie Wu,Wenquan Yu,Junbiao Chang
An intramolecular aryl C−H amination reaction has been achieved using molecular iodine as the sole oxidant for the synthesis of benzimidazole derivatives. The required substrates were readily prepared by addition or coupling of arylamines with the corresponding nitriles or aryl iodides. Iodine-mediated oxidative cyclization of these substrates in the presence of potassium carbonate (K 2 CO 3 ) as base afforded the corresponding products in moderate to good yields. The transition metal-free protocol presented here is insensitive to air and operationally simple. This versatile and eco-friendly synthetic methodology is broadly applicable to a variety of N -aryl-substituted amidines and pyridin-2-amines, and provides direct access to both 1 H -benzo[ d ]imidazole and pyrido[1,2- a ]benzimidazole derivatives from the corresponding precursors.
研究领域:
有机化学
·
药物化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Miao Wang,Yijin He,Xiaoyu Yang,Xuhui Hou,Wenxuan Li,Shaobo Tan,Zhicheng Zhang
With the increasing demand for dielectric materials in high-frequency microwave applications, fluoropolymer-based dielectric materials have been widely utilized due to their excellent dielectric and insulation properties. However, the low thermal conductivity limits their ability to meet the thermal dissipation requirements during high-frequency and high-speed signal transmission. The present study introduces a pioneering interface engineering strategy wherein C–F bonds on the surface of ethylene-tetrafluoroethylene copolymer (ETFE) are photo-catalytically activated, enabling successful grafting of poly(glycidyl methacrylate) (PGMA) chain segments. Subsequently, the resulting graft copolymers are blended with thermally conductive h-BN filler to prepare composite dielectric materials. The results demonstrate that the incorporation of PGMA segments significantly enhances the interfacial compatibility between the ETFE matrix and h-BN filler, resulting in composites with a dense microstructure and outstanding dielectric and thermal properties. At a filler content of 30 vol%, the ETFE-g-PGMA@BN composite achieves an in-plane thermal conductivity of 4.2 W (m K)−1 and a through-plane thermal conductivity of 0.77 W (m K)−1. Moreover, at 1 GHz, the composite exhibits a dielectric constant of 2.2 and a dielectric loss of 0.004. This work presents a novel interface design strategy for surface modification of PTFE-based fluoropolymers, expanding their potential applications in printed circuit boards (PCBs) and providing a new direction for the design of polymer-based dielectric materials.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 9
·2132-2143
·
IF 5.726
Jie Zhang,Zhihua Huang,Lanjian Xu,Xiaomin Zhang,Xinzhi Zhang,Yangyang Yuan,Lei Xu
The methanol to hydrocarbons reaction over a unidimensional 10-membered-ring zeolite, H-ZSM-48, was investigated in the temperature range of 723–973 K. C3–5 olefins were the dominant products of reaction at 723 K. Multiple approaches (constant, transient, co-feed and isotope labelling experiments) have been adopted to clarify the underlying reaction pathway. The results indicate that both of the olefin- and aromatics-based cycles contribute to light olefin formation, and the aromatics-based cycle can be significantly enhanced with increasing reaction temperature. Ethene is formed predominantly from the aromatics-based cycle while propene and higher olefins are mainly derived from the olefin-based cycle. The 12C/13C-methanol isotopic switching experiments manifest that hexamethylbenzene is the most active aromatic intermediate. Co-feeding of 13C-methanol and 12C-benzene at 543 K reveals that the paring mechanism is the dominant mechanism for aromatic dealkylation. More importantly, the first experimental evidence that the two carbons of ethene are derived from aromatic ring carbons is obtained based on the isotopic pattern. Furthermore, the investigation on coke-covered H-ZSM-48 reveals that the reaction of methylbenzenes occurs mainly inside the channels. This work will shed new light on the reaction pathway of the MTH reaction over unidimensional zeolites.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
Lubricants
·
2024
·Vol. 12
·期 5
·163
·
IF 3.1
Yunqi Fang,Yang Sun,Fengqin Shang,Jing Zhang,Jiayu Yao,Zihan Yan,Hangyan Shen
Van der Waals heterostructures with incommensurate contact interfaces show excellent tribological performance, which provides solutions for the development of new solid lubricants. In this paper, a facile electrostatic layer-by-layer self-assembly (LBL) technique was proposed to prepare multi-layer van der Waals heterostructures tungsten disulfide/hexagonal boron nitride (vdWH WS2/h-BN). The h-BN and WS2were modified with poly (diallyldimethylammonium chloride) (PDDA) and sodium dodecyl benzene sulfonate (SDBS) to obtain the positively charged PDDA@h-BN and the negatively charged SDBS@WS2, respectively. When the mass ratio of PDDA to h-BN and SDBS to WS2were both 1:1 and the pH was 3, the zeta potential of PDDA@h-BN and SDBS@WS2were 60.0 mV and −50.1 mV, respectively. Under the electrostatic interaction, the PDDA@h-BN and SDBS@WS2attracted each other and stacked alternately along the (002) crystal plane forming the multi-layer (four-layer) vdWH WS2/h-BN. The addition of the multi-layer vdWH WS2/h-BN (1.0 wt%) to the base oil resulted in a significant reduction of 33.8% in the friction coefficient (0.104) and 16.8% in the wear rate (4.43 × 10−5mm3/(N·m)). The excellent tribological property of the multi-layer vdWH WS2/h-BN arose from the lattice mismatch (26.0%), a 15-fold higher interlayer slip possibility, and the formation of transfer film at the contact interface. This study provided an easily accessible method for the multi-layer vdWH with excellent tribological properties.
研究领域:
材料科学
·
摩擦学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2019
·Vol. 125
·期 2
·1-10
·
IF 1.784
Chai Chen,Liu Jianxin,Wang Yawen,Zhang Xiaochao,Duan Donghong,Fan Caimei,Wang Yunfang
A h-WO 3 decorated Ag–AgCl composite was prepared through facile precipitation and photoreduction methods and demonstrated to be a highly efficient and stable photocatalyst for the degradation of Rhodamine B (RhB) under visible light. Ag–AgCl/h-WO 3 exhibited much improved photocatalytic performance was elucidated from the physical–chemical properties of AgCl and h-WO 3 and the surface plasmon resonance effect of the Ag particles. The techniques of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectrometry (XPS) and photocurrent were used to characterize crystalline phases, morphology, composition and separation efficiency between electrons (e − ) and holes (h + ) of the synthesized composite photocatalyst. XPS results confirmed the existence of W 5+ and W 6+ on the surface of h-WO 3 sample, which favored electrons transfer between AgCl and Ag, and generated superoxide radical for the degradation of RhB. The active species trapping experiments results further demonstrated that the formation of superoxide radical during the system. Finally, the underlying photocatalytic mechanism for the removal of RhB by Ag–AgCl/h-WO 3 composite was examined.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2022
·
IF 9.988
Jijie Kong,Xiaoyu Cao,Wen Huang,Chao Li,Qiming Xian,Shaogui Yang,Shiyin Li,Cheng Sun,Huan He
The occurrence of nitrated polycyclic aromatic hydrocarbons (NPAHs) in sediments has been widely reported, but research on NPAH bioavailability is lacking. In this study, a self-made zeolite imidazolate framework-8/hexagonal boron nitride (ZIF-8/h-BN) solid-phase microextraction (SPME) fiber and commercial Tenax are compared as efficient tools to predict the bioavailability of NPAHs in sediments with bioassays using Cipangopaludina chinensis . During the process of SPME, the NPAH concentrations on the ZIF-8/h-BN fibers reached extraction equilibrium after 72 h. The fiber extraction of NPAHs in sediments was well-fitted by the pseudo first-order kinetic model with a rate constant of 2 × 10 −2 h −1 (R 2 > 0.98). The extraction rates ranking of NPAHs in sediments was 2-nitrobiphenyl>1-nitropyrene>5-nitroacenaphthene>2-nitrofluorene. Compared with SPME, NPAH concentrations reached equilibrium after 168 h for the Tenax extraction. The orders of magnitude of fast, slow, and very slow desorption rate constants were 10 −1 , 10 −2 , and 10 −4 , respectively. At extraction equilibrium (168 h), the SPME was close to the bioavailability of the NPAHs in sediments to Cipangopaludina chinensis with a slope statistically approximated to one. In addition, the linear regression for SPME (R 2 = 0.7285) was slightly higher than that of the Tenax extraction (R 2 = 0.7168) over a short time (6 h). This could be because the coating material of ZIF-8/h-BN can rapidly adsorb freely dissolved NPAHs, and the SPME fibers can accurately predict the bioaccumulated concentrations of NPAHs in exposed organisms by measuring the concentration of NPAHs in the pore water of sediment. This study provides a time-saving and easy procedure to predict the bioavailability of NPAHs in sediments.
研究领域:
环境科学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Jianfeng Fan,Jiarong Huang,Liming Cao,Shiheng Yin,Yukun Chen
Recyclable polyvinylidene fluoride/silicone rubber (PVDF/SR) thermoplastic vulcanizates (TPVs) containing a high mass ratio of SR (50%) with excellent mechanical performances and shape memory behavior were fabricated. The inert PVDF was first dehydrofluorinated via β-H elimination reaction to introduce reactive double bonds. Then, the functional groups were initiated by dicumyl peroxide (DCP) during dynamic vulcanization to realize interfacial grafting (SR-g-PVDF) simultaneously. In situ grafted PVDF chains tightly bridge the immiscible phases, leading to the excellent interfacial adhesion. Consequently, the tensile strength, elongation at break, and tensile toughness were significantly increased to 14.5 MPa, 174.6%, and 12.3 kJ/m3, respectively, which were almost 2.0, 13.6, and 10.3 times than that without interfacial grafting reaction (7.2 MPa, 12.8%, and 1.2 kJ/m3). Also, their excellent mechanical properties were almost perfectly maintained after multiple repetitive processing. Furthermore, the chemical anchoring structure of SR-g-PVDF across the interface could effectively and quickly transfer the force, contributing to the shape memory performances. The obtained TPVs (m60 and m80) showed an impressive shape recovery ratio (>80%) even after two fixing-recovery cycles.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
ACS Catalysis
·
2021
·
IF 13.084
Xiangdong Long,Jia Wang,Guang Gao,Chao Nie,Peng Sun,Yongjie Xi,Fuwei Li
Direct oxidative amination of the sp3 C–H bond is an attractive synthesis route to obtain amides. Conventional catalytic systems for this transformation are based on transition metals and complicated synthesis processes. Herein, direct and efficient oxidative amination of the methyl C–H bond in a wide range of N-heterocycles to access the corresponding amides over metal-free porous carbon is successfully developed. To understand the fundamental structure–activity relationships of carbon catalysts, the surface functional groups and the graphitization degree of porous carbon have been purposefully tailored through doping with nitrogen or phosphorus. The results of characterization, kinetic studies, liquid-phase adsorption experiments, and theoretical calculations indicate that the high activity of the carbon catalyst is attributed to the synergistic effect of surface acidic functional groups (hydroxyl/carboxylic acid/phosphate) and more graphene edge structures exposed on the surface of carbon materials with a high graphitization degree, in which the role of acidic functional groups is to adsorb the substrate molecule and the role of the graphene edge structure is to activate O2.
研究领域:
有机化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Fuhai Liu,Maozhong Yi,Liping Ran,Yicheng Ge,Zhe Zhou,Ke Peng
C/C-BN-SiC composite was prepared by ceramic slurry infiltration combined with resin impregnation and carbonization, and the matrix with continuous distributed self-healing phase was obtained. In this study, the kinetic characteristics and oxidation behavior of the composites with various h-BN/SiC ratios in the temperature range of 600∼1300°C were studied by combining the isothermal oxidation test with the kinetic model. The optimal h-BN/SiC ratio balances the thermal stability and fluidity of the oxidized product, which not only has high thermal stability and low oxygen permeability to acts as an oxygen diffusion barrier but also has a certain fluidity to seal defects.
研究领域:
材料科学
·
热力学
✓ 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）