MICROPOROUS AND MESOPOROUS MATERIALS
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2017
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IF 3.615
Jun Zhang,Dan Yue,Tifeng Xia,Yuanjing Cui,Yu Yang,Guodong Qian
A novel metal-organic framework film MIL-124 film was prepared on porous α-Al 2 O 3 ceramic plate by in situ synthesizing. After introducing Eu 3+ ions to the free -COOH sites of the MIL-124 ligand channels, a luminescent MOF film MIL-124@Eu 3+ was obtained. Based on the chemical reaction between NH 3 and the -COOH, the formation of -COONH 4 which was demonstrated by FT-IR spectrum, affected the energy transfer between Eu 3+ ions and ligand, quenching the characteristic emission of MIL-124@Eu 3+ film. The limit of detection to ammonia was calculated as 26.2 ppm in ambient air. The XRD results demonstrated the long-term stability of this ammonia sensor. The excellent performance and economical synthesizing strategy of the MIL-124@Eu 3+ film exhibited potential application of this sensor for detecting ammonia gas.
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高影响因子
RSC Advances
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2016
·Vol. 6
·期 56
·51221-51228
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IF 3.289
Yanliang Yang,Jiping Ma,Xiuquan Jia,Zhongtian Du,Ying Duan,Jie Xu
Al2O3 modified by alkaline earth metals M–Al2O3 (M = Mg, Ca, Sr, Ba) was synthesised by coprecipitation method. The nickel-based catalysts supported by M–Al2O3 were prepared by impregnation method. The catalysts were characterized by TEM, N2 adsorption/desorption, XRD, H2-TPR, NH3-TPD and XPS, and used for the direct hydrogenation of furfural to tetrahydrofurfuryl alcohol (THFA) in water. The reaction was demonstrated to proceed through furfuryl alcohol as an intermediate. The modification of Al2O3 by alkaline earth metals has a significant effect on the activity and selectivity of THFA. A high yield of THFA was obtained over Ni/Ba–Al2O3 under optimized conditions. Moreover, the catalyst is recyclable and reusable at least four times without significant loss of the conversion of furfural and selectivity of THFA.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2017
·
IF 4.233
Di Zhang,Lijun Xue,Yongqiang Xu,Lijuan Song,Xinmei Liu
Mesoporous γ-Al 2 O 3 supports with different pore structures were prepared by the cation-anion double hydrolysis method. Based on these samples, MoO 3 /γ-Al 2 O 3 catalysts were made via impregnation. The adsorptions of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and collidine over the supports and catalysts were studied by FT-IR. The supports or catalysts with larger pores can adsorb more 4,6-DMDBT. The methyl groups on adsorbate molecules are very close to the sulfur atom , resulting in apparent steric hindrance . Increasing the pore size can promote the interaction between the adsorbates and supports or catalysts, enhancing the C C bond and weakening the C S bond of 4,6-DMDBT. 4,6-DMDBT molecules were coordinated with the unsaturated Mo atoms over the catalysts to form π-complexation adsorption. There was much difference between thiophene and 4,6-DMDBT adsorption. The adsorption of collidine over the catalysts also illustrated that there existed steric hindrance. Significantly, the catalyst with hierarchical mesopores was beneficial for the adsorbates with larger molecular dynamics diameter. Compared with the pore size, the specific surface area was not the key factor to affect the adsorptions of 4,6-DMDBT and collidine. The hydrodesulfurization reaction of 4,6-DMDBT illustrated that the catalysts with larger pore size or hierarchical pore structure presented higher desulfurization efficiency (above than 80%).
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2016
·
IF 3.205
Zhiming Gao,Lin Cui,Hongwei Ma
Four methods were adopted to prepare samples 20%NiO/Al 2 O 3 with calcination fixed at 500 °C, which were then reduced into 20%Ni/Al 2 O 3 and used as catalysts for reaction of selective methanation of CO in H 2 -rich gas (CO-SMET). XRD and TPR measurements indicate that nickel aluminates were formed in the calcined samples and their formation was influenced by preparation methods. Higher temperatures were required to reduce the calcined samples more efficiently and to achieve a higher catalytic activity for CO-SMET. Among the four methods, the precipitation method using ammonium carbonate as precipitant produced the highest catalytic activity both for CO methanation and for CO 2 methanation after reduction at 800 °C for 2 h. The calcined sample 20%NiO/Al 2 O 3 prepared with the method was therefore used as support and impregnated with Ru 3+ solution. Ru addition promoted reduction of Ni 2+ ions in the calcined sample even at the low temperatures of 400 °C and 500 °C. The catalyst 1%Ru–20%Ni/Al 2 O 3 reduced at 500 °C thus had a superior performance, removing CO to ca. 30 ppm with a selectivity as high as 75% at reaction temperature of 220 °C.
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THIN SOLID FILMS
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2017
·
IF 1.879
Xueyao Xie,Xin Yin,Lixin Song,Pingfan Du,Ni Li,Lin Qi,Jie Xiong
The flexible Al 2 O 3 /carbon composite nanofibers (ACNFs) film was synthesized by electrospinning. And the effects of carbonization temperature on the structures and properties of ACNFs were investigated. All the obtained ACNFs had rough surface and random orientations, and the alumina nanostructures were closely jointed to the carbon nanofibers . Besides, the crystallinity of alumina and carbon increased with carbonization temperature. As a result, the flexural property of ACNFs film decreased, and the electrical property greatly increased with the increase of carbonization temperature. When the carbonization temperature was 900 °C, the flexible ACNFs composite film was used as a counter electrode for flexible dye-sensitized solar cells. A power conversion efficiency of 2.84% was achieved. If the catalyst activity of the film was further improved, the conversion efficiency may be further improved.
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高影响因子
RSC Advances
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2015
·Vol. 5
·期 67
·54757-54761
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IF 3.84
Songjie Fan,Shan Wu,Jianhua Liu,Dan Liu
The synthesis conditions of MIL-120 membranes supported by a-Al2O3 hollow ceramic fibers (HCFs) were studied systemically. The continuous and compact MIL-120 membranes were successfully synthesised by secondary growth with in situ seeding step. The MIL-120 membrane shows the separation factors of H2–CO2, H2–CH4 and H2–N2 are 9.4, 7.9, and 7.3 respectively at 293 K and 1 bar with H2 permeance of 3.5 × 10−7 mol m−2 s−1 Pa−1 as well as high thermal stability.
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Analytical Methods
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2015
·Vol. 7
·期 8
·3486-3492
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IF 1.821
Houmei Liu,Yong Guo,Xusheng Wang,Xiaojing Liang,Xia Liu
In this paper, a novel sorbent, nano-Al2O3 coated mesoporous silica (Al2O3/SiO2), was prepared and used as a sorbent for solid-phase extraction of flavonoids. The synthesized sorbent material was characterized by X-ray photoelectron spectroscopy, energy dispersive spectroscopy and inductively coupled plasma emission spectrometry. The extraction properties of the resultant sorbent were evaluated by using four flavonoids (myricetin, quercetin, luteolin and kaempferol) as the test analytes. The extraction efficiencies of Al2O3/SiO2 were apparently superior to those of commercial C18 sorbents. Under optimal conditions, good linearities with R2 ranging from 98.8% to 99.8% were obtained and the LODs and LOQs were found to be in the range of 0.5–1 μg L−1 and 2.5–3 μg L−1, respectively. The proposed method was successfully applied for the real sample analysis of wild honey and red grape juice.
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高影响因子
FUEL PROCESSING TECHNOLOGY
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2014
·
IF 3.019
Wen Du,Libao Yin,Yuqun Zhuo,Qisheng Xu,Liang Zhang,Changhe Chen
Copper based sorbents are used to control mercury emissions in coal-fired flue gas . CuO x impregnated on neutral Al 2 O 3 (CuO x –Al 2 O 3 ) sorbents were found to enhance catalytic oxidation of elemental mercury in the presence of hydrogen chloride (HCl). The Hg 0 oxidation rates increased along with the increasing HCl concentration and temperature. The mercury oxidation rates were over 65% in the presence of 50 ppm HCl and the mercury adsorption amounts were over 75% in the early stage of the mercury removal process. CuO x –Al 2 O 3 sorbents demonstrated good mercury removal capacity. The effect of HCl is due to the formation of active chlorine. CuO x –Al 2 O 3 sorbents also have excellent sulfur resistance in the presence of HCl. A mixture of CuO x –Al 2 O 3 and activated carbon can remove more than 90% Hg 0 with a lower mercury removal cost for industrial applications. The characterizations of the CuO x –Al 2 O 3 sorbents were measured suggesting CuO x species work as catalysts via the redox shift between Cu 2 + and Cu + . The mercury oxidation mechanism of the sorbents is proposed to follow the Mars–Maessen mechanism.
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JOURNAL OF POWER SOURCES
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2014
·
IF 5.211
Xiaoyan Liu,Zhongqiang Shan,Kunlei Zhu,Jiangyong Du,Qiwei Tang,Jianhua Tian
Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies due to their high theoretical specific energy of 1675 mAh g −1 . However, the rapid capacity degradation, mainly caused by polysulfide dissolution, remains a significant challenge prior to practical applications. In this work, a sulfur cathode modified by bifunctional nafion/γ-Al 2 O 3 membrane has been successfully prepared, which can remarkably immobilize the polysulfides within the unique cathode structure due to its ions selectivity and absorbent capacity. A high initial discharge capacity of 1448.0 mAh g −1 can be achieved at 1C and 788.6 mAh g −1 preserved after 200 cycles, indicating a slow degradation. Furthermore, the coulombic efficiency maintains as high as 97% during cycling. The excellent electrochemical properties can be attributed to the bifunctional and stable membrane which can dramatically reduce the shuttle effect and keep integrated even after charging–discharging for 200 cycles.
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SENSORS AND ACTUATORS B-CHEMICAL
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2017
·
IF 5.401
Youling He,Jiangling He,Li Wang,Zhonghang Yu,Haoran Zhang,Yingliang Liu,Bingfu Lei
A new type of ratiometric fluorescent sensor was fabricated in a facile and low-cost process via sequentially assembling blue-light-emitting luminescent carbon dots (BCDs) and red-light-emitting carbon dots (RCDs) into the pores of mesoporous aluminas (MAs) through hydrogen band interactions. The advantages of the resultant BCDs/RCDs/MAs co-doped materials are that their luminescence exhibits dual characteristic peaks of the BCDs and RCDs under a single excitation wavelength, and that they having high surface-to-volume ratios. The co-doped materials were monitored in different carbon dioxide (CO 2 ), oxygen (O 2 ), nitrogen (N 2 ), and water vapor (H 2 O) environments. Based on the energy transfer from the RCDs to BCDs, with the addition of oxygen, the characteristic fluorescence intensity of the RCDs is monotonically quenched, but that of the BCDs remains almost unchanged. These results allow for the fabrication of a ratiometric fluorescent sensor using BCDs as reference fluorophores, and RCDs as target sensitive fluorophores. The as-prepared ratiometric fluorescence sensor has a high sensitivity with a linear oxygen volume range from 0 to 100, and exhibits an extremely short response/regeneration time of 2–4 s. The BCDs/RCDs/MAs co-doped materials are highly sensitive and selective for the detection of oxygen.
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POLYMER COMPOSITES
·
2024
·
IF 4.8
Yuchen Yang,Sen Cheng,Zi Ye,Chunhua Lu,Kai Guo,Ning Zhu,Xin Hu
The interface between the polymer matrix and inorganic fillers plays a determinative role in dielectric properties of the composites. In this work, dielectric composites containing core-shell structured BaTiO 3 @Al 2 O 3 (BT@AO) nanoparticles and cyano functionalized cellulose (cyanoethyl cellulose, CEC) were prepared to achieve enhanced interface and dielectric properties. With the wide bandgap Al 2 O 3 (AO) shell, the carrier motion inspired by elevating electric filed and temperature was significantly impeded in the composites. Meanwhile, the moderate dielectric constant and surface energy of AO shell between CEC and BaTiO 3 (BT) alleviated the inhomogeneous local electric field distribution and improve the interfacial compatibility between inorganic filler and CEC matrix. As a result, enhanced dielectric properties including restrained dielectric loss (0.23 for BT@AO/CEC versus 0.51 for BT/CEC at 100 Hz), suppressed conductivity, increased breakdown strength and improved dielectric constant were accessed in the BT@AO/CEC composites. The excellent thermal conductivity of AO also offered the composites with additional advantage of low electrical conductivity at high temperature of 100°C (1.56 × 10 −10 S/cm) exhibiting two orders of magnitude smaller than that of pure CEC. Highlights Core-shell structured BaTiO 3 @Al 2 O 3 were prepared and incorporated into cyanoethylated cellulose to yield flexible nanocomposites. Carrier motion was significantly restricted by the wide band gap of Al 2 O 3 shell. Enhanced interfacial compatibility was accessed in the BaTiO 3 @Al 2 O 3 /CEC composite. Improved dielectric properties and thermal conductivity were achieved.
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CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Dewei Ma,Panli Zhu,Jun Huang,Xiuhua Cao
The research on low-temperature lead-free glass is of great significance for the miniaturization, integration and intelligence of current electronic products, as well as environmental protection. In this article, we report the preparation of low-temperature lead-free B 2 O 3 -BaO-ZnO-SiO 2 -Al 2 O 3 -TeO 2 glasses by a melt-quenching technique. With the increase of TeO 2 content in glass, the glass transition temperature and melting temperature of sintered glass powder decrease, while its wettability and acid corrosion resistance show an increasing trend. The application of glass powder in the sintering experiment of terminal electrode slurry further proves this viewpoint. Compared with the poor sintering performance of the slurry with TeO 2 -free glass powder, the slurry containing TeO 2 glass powder forms a very dense sintered solid, and the sintered slurry is tightly bonded to the ceramic substrate .
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