JOURNAL OF SOLID STATE CHEMISTRY
·
2022
·
IF 3.656
Jiale Zhu,Siyan Yan,Guohao Xu,Xuedong Zhu,Fan Yang
A variety of HZSM-5 zeolites with different b-axis thicknesses and SiO 2 /Al 2 O 3 were fabricated by simply modifying urea content and Al source feeding in the initial gel, respectively. Multiple characterization technologies including XRD , SEM, N 2 adsorption-desorption, NH 3 -TPD and Py-IR were employed to investigate physicochemical properties of these samples and the possible crystallization mechanism was proposed that adsorption of urea molecules on (010) facet was the key factor for fabricating thin-sheet HZSM-5 zeolites. The results of hexane cracking reaction revealed that the selectivities of light olefins reached 46.5% when controlling b-axis thickness to 340 nm, exceeding the control sample by 12.2%. Furthermore, the effect of SiO 2 /Al 2 O 3 under this b-axis thickness was also investigated and concluded that keeping SiO 2 /Al 2 O 3 to 200 could exhibit the optimum catalytic performance with the conversion of 95.5% and light olefins selectivities of 56.7%. The reaction conditions were optimized to be 600 °C at the N 2 flow rate of 25 mL/min and WHSV of 3 h −1 to arouse the best performance. Under this condition, the distribution of ethene and propene was quite close to that of thermodynamic equilibrium. Based on these results, the primary and secondary products were uncovered, and further the reaction pathway of hexane cracking was disclosed. This new strategy to synthesize sheet-like catalysts for enhancing the catalytic properties in hexane cracking also laid a solid foundation for the study of the catalysts on light oil cracking in industry.
研究领域:
化学工程
·
催化材料科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Huimin Li,Yanfei Chen,Panding Wang,Baosheng Xu,Yongbin Ma,Weibin Wen,Yazheng Yang,Daining Fang
To improve the thermal insulation and mechanical properties of lightweight carbon- bonded carbon fiber composites (CBCF), a porous CBCF decorated with nano SiO 2 -Al 2 O 3 aerogel was prepared by sol-gel impregnation. Results showed that the nano aerogel were uniformly assembled within the pores in the CBCF framework. The aerogel played a significant role on reducing the thermal conductivity of CBCF, which could be mainly ascribed to reduced radiation and gas thermal conductivity of CBCF. Moreover, the aerogel in the CBCF pores hindered the bending fracture or elastic bending/rotation of the fibers and enhanced the mechanical properties of the composites.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Yaochun Qiang,Zhifang Pan,Mingzhang Liang,Jianfei Xu,Xinyu Ye,Libin Xia,Weixiong You,Junxiang Fu,Hong Ming
Multilayered inorganic transparent materials have been widely used as laser materials, scintillators and phosphors due to their excellent combined properties or functions. However, owing to the limitation of the current preparation technology, only the ceramics with cubic crystal structure could be fabricated into multilayered transparent materials, which has greatly obstructed the diversity of multilayered transparent materials. Here we report a novel non-cubic multilayered transparent phosphor with a ceramic/glass/ceramic sandwich-like structure prepared by controlling crystallization from Eu 2 O 3 -SrO-Al 2 O 3 -SiO 2 bulk glass. The ceramic thicknesses, total transmittances, emission colors and the fluorescence quantum yields of the samples can be adjusted continuously within a certain range. The multilayered transparent phosphor could be used as a potential candidate for the white LEDs with high color rendering index. It can be anticipated that the controlled crystallization from bulk glass method is a simple, fast, cost-effective and promising synthesis approach to prepare non-cubic transparent materials with ceramic/glass/ceramic structures.
研究领域:
材料科学
·
光学材料
·
陶瓷
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固态照明
·
光致发光
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2012
·
IF 2.947
Fang Hao,Jun Zhong,Ping-Le Liu,Kui-Yi You,He-An Luo
The amorphous SiO 2 –Al 2 O 3 supported Co 3 O 4 catalysts were prepared by impregnation method and characterized by SEM, BET, XRD, XPS, NH 3 -TPD and FT-IR. The influences of the preparation conditions including the loading content of cobalt and the calcination temperature were studied in detail. The results show that the supported Co 3 O 4 /SiO 2 –Al 2 O 3 catalysts possess both Lewis and Brønsted acid sites and the amount of the Brønsted acid sites increases with the increment of the loading content of cobalt. The 20% Co 3 O 4 /SiO 2 –Al 2 O 3 catalyst calcinated at 500 °C shows relative larger surface area and pore diameter, smallest and uniform particle size, well dispersed of Co 3 O 4 . And it has the largest amount of Brønsted acid sites because it occupies the highest content of cobalt and Co 2+ . The relationship between the catalytic performances and the characterization results suggests that the Brønsted acid sites are the selective sites for the cyclohexane nitrosation to ɛ-caprolactam. The 20% Co 3 O 4 /SiO 2 –Al 2 O 3 calcinated at 500 °C gives the best result of conversion of 11.2% and ɛ-caprolactam selectivity of 83.3%, which is the best result since one step synthesis of ɛ-caprolactam from cyclohexane nitrosation was developed.
研究领域:
催化化学
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材料化学
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化学工程
✓ 已验证
DOI
高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 31
·e202300799
·
IF 2.1
Lin-Jie He,Yao-Feng Wang,Peng-Xin Guan,Qing-Shan Niu,Hong-Ying Liu,Bao-Hua Xu
The vapor-phase nitrilation of dimethyl adipate (DMA) with ammonia (NH 3 ) is an environmentally benign route leading to adiponitrile (ADN) with great application value. In this study, the performance of HZSM-5 zeolites, widely used in industry as the solid acid catalysts, was investigated. It exhibits a strong correlation between the SiO 2 /Al 2 O 3 ratio (SAR) in HZSM-5 zeolites and the reactivity (both activity and selectivity). The influence of Al density closely related to the value of SAR on the reactivity of HZSM-5 was thus elucidated by mechanistic experiments. As a result, the introduction of Al element to the framework is beneficial to the activation of ester functionality, thus improving the activity, especially at a high liquid hourly space velocity (LHSV). However, a high Al density will lead to poor selectivity and deactivation due to too strong adsorption of esters and intermediates (e. g., amides). Herein, the balanced adsorption/desorption capability was reached on HZSM-5 with SAR as 631 (i. e., HZSM-5-631), which provides the best selectivity to nitriles (S ADN+MCP , 92.5 %) at a high single-pass conversion of DMA (C DMA , 98.0 %). Graphical The nitrilation of DMA over HZSM-5 with different SiO 2 /Al 2 O 3 was investigated, wherein HZSM-5 with SiO 2 /Al 2 O 3 of 631 exhibited excellent reactivity due to the balance of ester activation and amide intermediate desorption.
研究领域:
催化化学
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化学工程
·
绿色化学
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材料科学
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有机合成
✓ 已验证
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2022
·Vol. 29
·期 2
·248-255
·
IF 3.85
Ren Guoxing,Xiao Songwen,Liao Caibin,Liu Zhihong
As a part of the fundamental study related to the reduction smelting of spent lithium-ion batteries and ocean polymetallic nodules based on MnO-SiO 2 slags, this work investigated the activity coefficient of NiO in SiO 2 -saturated MnO-SiO 2 slag and Al 2 O 3 -saturated MnO-SiO 2 -Al 2 O 3 slag at 1623 K with controlled oxygen partial pressure levels of 10 −7 , 10 −6 , and 10 −5 Pa. Results showed that the solubility of nickel oxide in the slags increased with increasing oxygen partial pressure. The nickel in the MnO-SiO 2 slag and MnO-SiO 2 -Al 2 O 3 slag existed as NiO under experimental conditions. The addition of Al 2 O 3 in the MnO-SiO 2 slag decreased the dissolution of nickel in the slag and increased the activity coefficient of NiO. Furthermore, the activity coefficient of NiO ( γ NiO ), which is solid NiO, in the SiO 2 saturated MnO-SiO 2 slag and Al 2 O 3 saturated MnO-SiO 2 -Al 2 O 3 slag at 1623 K can be respectively calculated as γ NiO = 8.58 w (NiO) + 3.18 and γ NiO = 11.06 w (NiO) + 4.07, respectively, where w (NiO) is the NiO mass fraction in the slag.
研究领域:
冶金学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2026
·
IF 6.6
Tianyu Zhang,Dong Han,Wenkang Yi,Zhihong Wang,Ruina Ma,An Du,Yongzhe Fan,Xue Zhao,Xiaoming Cao
Achieved coatings exhibiting coexistence of crystalline and amorphous SiO 2 phases. • Revealed the three-dimensional distribution and phase composition of coating pores. • Elucidated the mechanism by which SiO 2 coatings influence thermal management performance. • I corr is reduced by more than two orders of magnitude compared to the matrix. This study addresses the insufficient thermal stability and corrosion resistance of 7075 aluminium alloy by employing staged voltage-boosted plasma electrolytic oxidation (PEO) technology to fabricate an ultra-thick composite coating containing amorphous/crystalline SiO 2 within an organosilicon electrolyte. The system investigated the regulation mechanisms of duty cycle on coating phase composition, microstructure, thermal control performance, and corrosion resistance. Utilising advanced characterisation techniques such as Grazing Incidence X-Ray diffraction, X-ray computed tomography, and X-ray photoelectron spectroscopy, its underlying mechanisms were elucidated. By modulating energy input, the duty cycle significantly influenced coating growth, achieving a maximum thickness of 181.76 μm-far exceeding conventional PEO coating thickness levels. XCT analysis revealed the phase distribution and pore characteristics of the coating at a 20% duty cycle. Pores with diameters between 0 and 5 μm constituted the highest proportion (approximately 68.85%), while interconnected pores exceeding 30 μm in diameter dominated the total pore volume. Optimal thermal management performance was observed at a 30% duty cycle (absorptance 0.36, emissivity 0.89), confirming a critical thickness threshold (130 μm) and the pivotal role of amorphous SiO 2 . Corrosion resistance peaked at a 10% duty cycle, with corrosion current density reduced to 2.368 × 10 −8 A·cm −2 , representing a near two-order-of-magnitude decrease compared to the substrate. Download: Download high-res image (349KB) Download: Download full-size image
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
·
2019
·
IF 2.683
Kai Sun,Shuai Feng,Qian Jiang,Xiaofeng Li,Yaping Li,Runhua Fan,Yan An,Jiaqi Wang
The soft magnetic composites (SMCs) with high saturation magnetic flux density ( B s ) and low core loss ( P s ) have great potential in power electronics. In this work, the insulating SiO 2 -Al 2 O 3 layer was prepared by a hydro-thermal method to coat on the surface of the carbonyl iron powders (CIPs). Then, the coated CIPs were heterogeneously distributed in the reduced iron powders (RIPs) to fabricate the intergranular insulated SMCs. The scanning electron microscope (SEM) images and elements analysis confirmed that the surface of the CIPs was covered by a thin insulating layer forming a core-shell structure, and the Si-O-Al bond was detected by FTIR spectra. The resulting samples were annealed at 450 °C in N 2 atmosphere to eliminate the residual stress and improve magnetic properties. The annealed. SMCs containing 25 wt% CIPs@SiO 2 -Al 2 O 3 have optimum magnetic properties with a low P s of 106.9 W/kg and a highly approximate B s of 1.28 T (measured at 500 Hz). Compared with the conventional SMCs, the addition of the coated CIPs can suppress the adverse effect of the nonmagnetic coating layer on magnetic properties; meanwhile, the coated CIPs distributed in the RIPs can reduce the P s . This work provides a promising approach to the development of SMCs with low hysteresis loss and optimum magnetic properties at low frequency.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Shiao Gao,Ahui Ma,Zhennan Yang,Sida Ge,Zhuwen Zhang,Zhijie Wu
ZSM-48 zeolite is characteristic of 10-member ring (10-MR) one-dimensional tubular channel structure and finds extensive applications in catalytic hydroisomerization reactions. Here we developed an efficient synthetic strategy for low-silica ZSM-48 zeolite with a SiO 2 /Al 2 O 3 ratio at 30–176 via a seed-assisted hydrothermal synthesis method, overcoming the limit that 1,6-hexanediamine (HDA) template can only be used to synthesize high-silica (i.e., SiO 2 /Al 2 O 3 ratio >200) zeolites. A two-step crystallization procedure coupled with zeolite seed-assisted synthesis strategy was enrolled to realize well crystallized ZSM-48 zeolites, in which the zeolite nuclei are sufficiently produced at the nucleation temperature at 100 °C for 24 h with the aid of zeolite seeds, and the zeolite growth is proceeded at the crystallization temperature at 160 °C for 48 h. The morphology and particle size of low-silica ZSM-48 zeolite have been manipulated by adjusting the synthetic parameters, such as the alkalinity and silicon source of aluminosilicate gel for zeolite, the crystallization manner (static or dynamic crystallization), as well as the presence of additive (i.e., sodium chloride). The as-synthesized ZSM-48 zeolite possesses a high acid content of 0.194 mmol/g, highlighting its potential as an excellent acidic support for hydroisomerization catalysts. The cost-effective and environmentally friendly synthesis strategy, which is anticipated to expand the application of alkylamine organic templates in the synthesis of low-silica ZSM-48 zeolite.
研究领域:
材料科学
·
化学工程
·
催化
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhe-Hui Zhang,Meng-Ying Liu,Zhuohua Sun,Katalin Barta,Tong-Qi Yuan
Funneling complex lignocellulose into simple and valuable building blocks has garnered significant interest in the field of biorefinery as a competitor to the petrochemical industry. Reductive Catalytic Fractionation (RCF) of lignocellulose, an innovative biorefinery technology, provides a promising strategy for complete valorization of lignocellulose into various valuable chemicals. In this study, integrated processes utilizing RCF strategies were developed to achieve complete conversion of lignocellulose into various simple and valuable platform chemicals. The core of this system is the flexible use of commercial Ni catalysts including Raney Ni and Ni/SiO 2 -Al 2 O 3 which brings great benefits for future upscale and industrial applications. Surprisingly, both monomers derived from lignin and high molecular weight fractions could be converted to 4-ethylcyclohexanol while carbohydrate pulp was converted to furfural and 5-methoxymethylfurfural (MMF) in one-pot. MMF could be further upgraded to 2,5-Furandicarboxylicacid (FDCA) via catalytic oxidation by Ru/C catalysts. This work could inspire the development of more sustainable and economically viable biorefinery processes.
研究领域:
生物精炼
·
化学工程
·
催化
·
可持续化学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2020
·Vol. 11
·期 1
·1-13
·
IF 12.121
Jia Chao,Li Lei,Liu Ying,Fang Ben,Ding He,Song Jianan,Liu Yibo,Xiang Kejia,Lin Sen,Li Ziwei,Si Wenjie,Li Bo,Sheng Xing,Wang Dongze,Wei Xiaoding,Wu Hui
Advanced ceramic sponge materials with temperature-invariant high compressibility are urgently needed as thermal insulators, energy absorbers, catalyst carriers, and high temperature air filters. However, the application of ceramic sponge materials is severely limited due to their complex preparation process. Here, we present a facile method for large-scale fabrication of highly compressible, temperature resistant SiO 2 -Al 2 O 3 composite ceramic sponges by blow spinning and subsequent calcination. We successfully produce anisotropic lamellar ceramic sponges with numerous stacked microfiber layers and density as low as 10 mg cm −3 . The anisotropic lamellar ceramic sponges exhibit high compression fatigue resistance, strain-independent zero Poisson’s ratio, robust fire resistance, temperature-invariant compression resilience from −196 to 1000 °C, and excellent thermal insulation with a thermal conductivity as low as 0.034 W m −1 K −1 . In addition, the lamellar structure also endows the ceramic sponges with excellent sound absorption properties, representing a promising alternative to existing thermal insulation and acoustic absorption materials.
研究领域:
材料科学
·
陶瓷工程
·
热绝缘
·
声吸收
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）