SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Lu Fan,Zhizhang Shen,Zhenyu Wang,Ji Li,Jinze Lyu
The deposited dust provides a large surface for heterogeneous ozone uptake reactions in urban regions. Prior studies have barely considered the effect of the photothermal conversion of deposited dust and underlying surface on ozone uptake. In this study, Fe 2 O 3 , TiO 2 , α-Al 2 O 3 , and SiO 2 were selected as model mineral dusts (MDs) to evaluate the photothermal effect. With an irradiation intensity of 100 mW/cm 2 , the uptake coefficients of ozone by Fe 2 O 3 , TiO 2 , α-Al 2 O 3 , and SiO 2 were 2.4, 30, 2.72, and 2.83 times higher than those in a dark condition. For SiO 2 and α-Al 2 O 3 , the increase in the uptake coefficient was due to the temperature increase induced by photothermal conversion. For Fe 2 O 3 and TiO 2 , photoelectric and photothermal conversion simultaneously participated in ozone uptake reactions. At 70 °C, the contribution of thermal catalysis to ozone uptake over Fe 2 O 3 and TiO 2 was approximately 55.4 % and 55.0 %, respectively. The temperature increase induced by photothermal conversion also promoted MDs' activity for ozone uptake after removing the light source (after sunset). This work proves that the ozone uptake induced by the photothermal effect of deposited MDs and the underlying surface was the primary ozone elimination pathway in urban atmospheres.
研究领域:
大气化学
·
环境科学
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PubMed
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Yu Qin,Li Xu,Liying Liu,Zhongwei Ding
An original synthesis strategy for tubular zeolitic imidazolate framework (ZIF) membranes was developed by the deposition of a novel porous amorphous hybrid material prepared by 3-isocyanatopropyltrimethoxysilane (IPTMS) and ZIF-8 crystals onto a coarse macroporous α-Al2O3 tubular support. This porous amorphous hybrid material (ZIF-8-IPTMS) not only strongly adhered to the support but also repaired the defects to make the support surface smooth due to the abundant hydroxyl groups and the appropriate particle size. Using this synthesis strategy, we successfully prepared a high-quality ZIF-8 membrane on an inorganic α-Al2O3 tubular support via the sufficient heterogeneous nucleation sites provided by the amino groups of ZIF-8-IPTMS. This ZIF-8 membrane with an ultrathin thickness of approximately 0.9 μm was prepared, and its ideal H2/CO2 selectivity increased as the temperature increased. The membrane exhibited a competitive selectivity of 13.8 with a remarkably high H2 permeance of 1.46 × 10–5 mol·m–2·s–1·Pa–1 at 90 °C and 0.1 MPa. H2/CO2 binary gas permeation measurements indicated a separation factor of 9.2, and the H2 permeance was maintained at 0.83 × 10–5 mol·m–2·s–1·Pa–1 at 90 °C and 0.1 MPa. This synthesis strategy was also suitable to fabricate ZIF-67 membranes. The ZIF-67 membrane with a thickness of approximately 1.2 μm exhibited a H2/CO2 ideal selectivity of 5.3 and maintained a high H2 permeance of 1.06 × 10–5 mol·m–2·s–1·Pa–1 at 35 °C and 0.1 MPa.
研究领域:
材料科学
·
化学工程
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·Vol. 49
·期 3
·4331-4341
·
IF 5.532
Zhou Yi,Shiyu Cui
α-Al 2 O 3 was coated on the powder surface using the precipitation method to improve the pre-oxidation resistance of molybdenum disilicide in thermal barrier coatings (TBCs). The coating effects of four different aluminum sources (Al(NO 3 ) 3 ·9H 2 O) to MoSi 2 mass ratios were evaluated by viscosity and micro-morphology. The shell-forming effects on the powder size and post-treatment were thoroughly analyzed to meet the requirements for practical application in TBCs. The results showed that the precipitation method was superior to the sol-gel process in terms of the shell thickness obtained. Optimal shell-forming was generated at 1200 °C in an inert atmosphere . A bonding layer (Al 6 Si 2 O 13 ) would be formed at the core-shell interface, further preventing oxidation penetration. The self-healing particles MoSi 2 @α-Al 2 O 3 can effectively seal micro-cracks (width below 300 nm) because of the fluidity of SiO 2 at working temperatures.
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CERAMICS INTERNATIONAL
·
2026
·
IF 6
Jinquan Wen,Guihua Liu,Tiangui Qi,Nianzi Liu,Qiusheng Zhou,Jian Guo,Leiting Shen,Yilin Wang
Alumina ceramics with full densification at low temperature are desirable owing to their enhanced mechanical properties and reduced energy consumption. However, resolving the inherent balance between density and reactivity remains a key challenge in pressureless sintering without additives. This work proposed a strategy for preparing low-temperature densified alumina ceramics via defect engineering and phase regulation in precipitated alumina trihydrate. Based on the pseudomorphic and topotactic transformations, highly reactive binary α-Al 2 O 3 powder was prepared by regulating the phase composition, structural defects and chemical coordination of the precursor alumina trihydrate via hydrothermal modification. Combining the high density of well crystallized gibbsite-derived α-Al 2 O 3 and the high reactivity of poorly developed boehmite-derived α-Al 2 O 3 , the binary α-Al 2 O 3 exhibited notably increased unsaturated Al coordination, enhanced microstrain, and decreased α-Al 2 O 3 content, enabling rapid sintering kinetics in grain boundary diffusion with a reduced activation energy of 302 kJ mol −1 . Meanwhile, sintering under nitrogen atmosphere facilitated the generation of oxygen vacancies and lattice distortion in the α-Al 2 O 3 powder. The lattice distortions of elongated Al-O bonds, increased interlayer spacing and expanded lattice volume further boosted the sintering activity of binary α-Al 2 O 3 powder by providing extensive diffusion tunnels for accelerated atomic migration. With remarkable grain refinement and improved microstructural homogeneity, the resultant binary alumina ceramic was fully densified at 1400 °C for 2 h with 99.9% relative density, 0.02% apparent porosity, 17.22 GPa Vickers hardness, 4.08 MPa m 1/2 fracture toughness, 8.34E + 12 Ω cm electrical resistivity and 34.35 W m −1 K −1 thermal conductivity. This study provides new insights into low-temperature densification of alumina ceramics, and improves the performance of alumina-bearing materials via structure-property modification of α-Al 2 O 3 powder and aluminum hydroxide precursors.
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CHEMICAL PAPERS
·
2025
·
IF 2.5
Gu Peng
Dielectric composites with high dielectric constant, minimal dielectric loss and low conductivity can well serve for energy storage capacitors. High dielectric loss is not favorable due to large energy waste. Here, to improve dielectric constant of poly(vinylidene fluoride–hexafluoropropylene) by electric percolation, semiconducting NiO filler was added to form composites. However, high leakage current from interfaces can lead to high dielectric loss. Doping insulating α-Al 2 O 3 particles with stable structure, low chemical activity and high modulus into above binary composites can reduce dielectric loss. By changing NiO dose, dielectric constant was well tailored. Dose of α-Al 2 O 3 was left unchanged. Dielectric loss, conductivity and dielectric constant of composites were measured. By the same NiO loading, dielectric loss, conductivity and dielectric constant in ternary composites can be reduced, compared with binary composites. The optimal ternary composite should contain 35 wt% NiO and 4 wt% α-Al 2 O 3 . Optimized dielectric traits of this composite can be reflected by dielectric constant of ~ 64 and dielectric loss of ~ 0.27 under 100 Hz electric field.
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FUSION ENGINEERING AND DESIGN
·
2017
·
IF 1.319
Heping Li,Zhiqiang Ke,Lihong Xue,Youwei Yan
α-Al 2 O 3 -based coatings have attracted great interest as promising tritium permeation barrier used in the D-T fusion reactor system. However, it is still difficult to fabricate α-Al 2 O 3 coatings at a low temperature that can be endured by the steel substrate. Herein, thermal-chemical reaction method was developed for the fabrication of α-Al 2 O 3 -based coatings. α-Al 2 O 3 /AlPO 4 composite coating was successfully formed on the steel substrate at 500 °C. The resulted coating was uniform and compact without presence of pores and cracks. The binding strength of the coating was tested and the result indicated its good adherence to the substrate. Moreover, the coating thickness could be easily controlled. The low-temperature approach developed is expected to provide a new platform for fabricating α-Al 2 O 3 -based coatings as tritium permeation barrier. This approach is also applicable to the fabrication of other ceramic coatings.
研究领域:
材料科学
·
核工程
·
陶瓷涂层
·
聚变反应堆技术
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Xiaolian Jing,Jiale Huang,Huixuan Wang,Mingming Du,Daohua Sun,Qingbiao Li
Supported Ag catalyst for ethylene epoxidation was prepared by an impregnation–bioreduction process with Cinnamomum camphora (CC) extract. Influence of bioreduction temperature, concentration of CC extract, silver loading amount, calcination temperature as well as Cs promoter on catalytic performance were thoroughly investigated and the catalysts were characterized. The results showed that the catalyst prepared from bioreduction process exhibited excellent performance for the ethylene epoxidation with O 2 . Proper amount of Cs addition could effectively improve the catalytic performance of the catalyst. The optimal catalyst 15Ag/α-Al 2 O 3 -150Cs gave the EO concentrations of 1.70%, EO selectivity of 87.46% and EO STY of 223.07 g h −1 L −1 cat at 200 °C, showing high catalytic stability with no significant decrease in the activity and the selectivity during 50 h.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 35
·期 1
·1-13
·
IF 2.8
Sun Qin,Yang Wanchun,Hu Zhongyu,Jia Gaozhi,Wang Yangyang
Copper pastes are widely used in metallization of ceramic surfaces but are limited by poor oxidation resistance, high resistivity, and low bonding strength. In this work, the 30Bi 2 O 3 –55B 2 O 3 –15ZnO glass powder was prepared by the melt-quenching method. A copper paste containing the glass powder and formic acid-treated copper microparticles was used for metallization of α -Al 2 O 3 ceramic surface. The copper thick films were obtained by low-temperature sintering after screen printing. The effects of the glass powder contents on resistivities and shear strengths of the copper films on α -Al 2 O 3 ceramic substrate were analyzed. The microstructures of the copper thick films and the interfacial bonding mechanism on the α -Al 2 O 3 ceramic surface were investigated in detail. The copper thick film with 10-wt% 30Bi 2 O 3 –55B 2 O 3 –15ZnO glass and sintered at 650 °C for 20 min exhibited a low resistivity (3.38 ± 0.94 µΩ cm) and a high shear strength (35.24 ± 1.2 MPa). ZnAl 2 O 4 and Bi 2 B 4 O 9 were detected on the edges of the copper film near the interface, which enhanced interfacial binding between the copper thick films and the α -Al 2 O 3 ceramic substrate. These results demonstrated that the low-temperature sintering copper paste containing 30Bi 2 O 3 –55B 2 O 3 –15ZnO glass was effective for α -Al 2 O 3 ceramic surface metallization.
研究领域:
材料科学
·
陶瓷
·
冶金学
·
电子封装
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高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Haiyang Chen,Jiale Wang,Ke Zhang,Mengyuan Du,Gaoxiang Ye,Mingjie Guo,Cong Gao,Weisu Weng,Bin Li,Junhong Chen
A novel spatial confined micro-domains method based on the polyacrylamide (PAM) gel carbonization for the synthesis of highly dispersed nano α-Al 2 O 3 was proposed. By optimizing the gel concentration and cross-linking degree, a carbon network featuring confined micro-domains was constructed to effectively inhibit the migration of alumina precursors during phase transformation. Under the influence of spatial confinement, well-dispersed α-Al 2 O 3 nanoparticles with high purity and an average size of approximately 98.3 nm were obtained at an Al 3+ concentration of 0.1 mol/L. FTIR, XPS analyses and first-principles calculations further revealed that the formation of Al-C bonds at the surface of α-Al 2 O 3 contributed to reducing surface energy and enhanced interfacial stability, which further restrained the growth and agglomeration of nano α-Al 2 O 3 . Notably, the alumina ceramics sintered from these nanoparticles exhibited a higher density and superior mechanical properties than commercial counterparts. This study offers a feasible confined-domain strategy for the controllable synthesis of high-performance nano α-Al 2 O 3 .
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高影响因子
LANGMUIR
·
2025
·
IF 3.9
Peng Wang,Qianpeng Dong,Chenyu Gao,Lianlian Wang,Ruiliang Wang,Dianming Chu,Wenjuan Bai,Yan He
This research presents a regulation strategy of constructing a heterogeneous bilayer catalyst of Fe and Al2O3, namely, Fe–Al2O3, through interfacial interaction and particle nucleation, in order to modulate the size and catalytic activity of Fe sites and achieve the growth of carbon nanotubes (CNTs). Through temperature control, the noncatalytically active Fe2O3 clusters on the surface of Al2O3 are exposed, inducing multiple nucleation of Fe clusters on its surface. Under the synergistic effect of the confinement at the Fe–Al2O3 interface, the fabrication of small Fe nanoparticles is accomplished. The results indicate that the catalytically active Fe nanoparticles have a diameter of approximately 10 nm, and the grown CNTs have a diameter of approximately 15 nm. Based on the systematic characterization results, the nonactive Fe2O3 clusters confined by strong interfacial interaction induce multiple nucleation of Fe on their surface during multiple loading processes, facilitating the formation of nanoparticles. Additionally, the strong interaction between Al2O3 and Fe induces the formation of FeAl4O8, thereby enhancing the thermal stability of the nanoparticles. In conclusion, the targeted regulation of the interfacial interaction of the catalyst active sites offers guidance for the low-cost and large-scale preparation of small nanoparticle catalyst particles.
研究领域:
材料科学
·
催化化学
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PubMed
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MATERIALS LETTERS
·
2014
·
IF 2.269
Jinna Zhang,Dandan Hao,Hui Lu,Wenguang Leng,Jianzhou Gui,Yanan Gao
A surface modification strategy was applied by using 3-aminopropyltriethoxysilane (APTES) covalent linkage between the Schiff-base networks (SNW) polymer layers and porous α-Al 2 O 3 ceramic support. The SNW-1 polymer membrane and powders resulting from the polycondensation reaction between melamine and terephthalaldehyde without the polycondensation catalysts were investigated by SEM and FT-IR. The results show that the discrete and few covered polymer layers were formed on the unmodified porous α-Al 2 O 3 support. In contrast, the uniform and compact SNW-1 polymer membrane was fabricated successfully on the APTES modified α-Al 2 O 3 support by in-situ catalyst-free polycondensation method, indicating that the APTES surface modification facilitates the growth of the novel SNW-1 polymer membrane on the porous α-Al 2 O 3 support.
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高影响因子
ACS Applied Materials & Interfaces
·
2026
·
IF 8.2
Jing Wang,Weida Shi,Minghui Qiu,Juanjuan Wen,Xianfu Chen,Yiqun Fan
Ceramic tight ultrafiltration (UF) membranes exhibit excellent chemical and thermal stability. However, increased pore size and limited separation accuracy caused by high temperature sintering remain challenges in their preparation and application. In this study, a facile lattice-doping strategy using Fe-doped sol–gel precursors was developed to fabricate α-Al2O3 tight UF membranes. Fe incorporation effectively promoted the γ → α phase transformation at a reduced temperature (950 °C), suppressed grain growth, and produced smaller and more uniformly distributed pores with an average size of 5.5 nm. Increasing Fe content further enhanced surface hydrophilicity, corrosion resistance in biotic systems, and pure-water permeability (130 L·m–2·h–1·bar–1). Nevertheless, excessive Fe loading (>10%) resulted in phase separation and pore size heterogeneity. The optimized 10% Fe-doped α-Al2O3 membrane exhibited outstanding separation performance, achieving a BSA rejection of 99.9% and a permeance of 80 L·m–2·h–1·bar–1, nearly double the value of the undoped membrane. It also showed a significantly improved normalized flux and a flux recovery ratio exceeding 80%, demonstrating excellent antifouling capability. Similar antifouling and high removal were also observed in humic acid separation. These compelling features highlight its potential for efficient water purification applications.
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高影响因子
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