INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2016
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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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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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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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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2017
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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
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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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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SENSORS AND ACTUATORS B-CHEMICAL
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2017
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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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Additive Manufacturing
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2024
·
IF 10.3
Qiuyu Liu,Qinchao Tang,Zhifeng Huang,Zhiwei Li,Xuye Wang,Pin Wen,Yi Bai,Fei Chen
Hydroxyapatite (HA) is widely used in scaffolds due to its high similarity in the composition to natural bone. However, the weak and fragile characteristics of synthetic HA limit its application. The strength of HA can be increased by the incorporation of alumina (Al 2 O 3 ) to obtain composites with extraordinary compressive strength and biocompatibility. HA-Al 2 O 3 composites with different ratios were prepared by Vat photopolymerization 3D printing, and their shrinkage, porosity, phase composition and biocompatibility were systematically investigated. In addition, the Diamond structure of the scaffold was chosen to achieve the trade-off relationship between compressive strength and porosity. The results suggest that the HA-Al 2 O 3 composite with 20 vol% HA possesses the maximum compressive strength and 60 vol% HA has optimal biocompatibility. A compositional gradient scaffold from 60 vol% HA and 20 vol% HA was proposed to satisfy different needs of the different parts in scaffold for biocompatibility and compressive strength. The HA-Al 2 O 3 gradient scaffold achieves a preferable compressive strength of 13.7 MPa while possessing gradient biocompatibility.
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POLYMER COMPOSITES
·
2024
·
IF 4.8
Lei Xie,Hongqiang Zhang,Yujian Liu,Yan Zhang
High thermal conductivity ( λ ) composite with excellent dielectric, mechanical, and thermal properties are critical to the reliability and safety of electrical devices. However, the excessive addition of thermal conductive fillers may lead to severe performance degradation. Heterogeneous structured alumina-hexagonal boron nitride nanosheets (Al 2 O 3 @BNNS) fillers were prepared by electrostatic self-assembly method. Owing to synergistic effect of spherical Al 2 O 3 and sheet BN, and much low interface thermal resistance, λ of the epoxy resin with 20 wt% Al 2 O 3 @BNNS 2 is raised to 0.84 W·m −1 ·K −1 , 86.67% higher than that of Al 2 O 3 /BN/EP composite. Furthermore, epoxy-based polyhedral oligomeric silsesquioxane (EP-POSS) was incorporated to further optimize dielectric property of the composite. The λ of the composite is slightly decreased, but the dielectric constant and dielectric loss are reduced to 2.954 and 0.01058, respectively, due to the unique cage structure of EP-POSS and excellent compatibility of EP-POSS with the matrix. The composite also exhibits favorable mechanical properties with an impact strength of 86.2 MPa and a bending strength of 7.81 kJ·m −2 , as well as outstanding thermal stability, suggesting its promising prospects for advanced electronic devices. Highlights f Al 2 O 3 and f BNNS electrostatic self-assemble into heterostructured fillers. The λ of Al 2 O 3 @BNNS 2 /EP composite is much higher than the others. The cage-like EP-POSS is used to improve dielectric properties of the epoxy resin. The ε and tan δ of composites at 1 MHz are only 2.954 and 0.01058, respectively.
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Journal of Energy Storage
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2024
·
IF 8.9
Tianran Zhang,Quanjiang Lv,Siyu Zhang,Mengfan Song,Siyuan Li,Lixue Zhang,Jiping Wang
In polymer dielectric energy storage, even polymers with high glass transition temperatures suffer significant degradation in energy storage performance as temperature increases, primarily due to a sharp rise in electrical conduction loss. In this study, we employ atomic layer deposition to coat the surface of a PEI/PVDF blend film with an Al 2 O 3 inorganic layer to enhance its energy storage performance at high temperatures. The influence of the inorganic layer's thickness on high-temperature energy storage performance is thoroughly analyzed. Experimental results and finite element simulations demonstrate that an ultra-thin Al 2 O 3 inorganic layer with the thickness of 50 nm effectively reduces leakage current density and mitigates space charge accumulation within the PEI/PVDF blends, thereby improving the high-temperature energy storage performance of the blends. Notably, under an applied electric field of 500 MV/m at 150 °C, the PEI/PVDF blend film with 50 nm Al 2 O 3 layer achieved a discharge energy density of 5.45 J/cm 3 and a charge-discharge efficiency of 97.75 %.
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Materials Today Communications
·
2024
·
IF 3.7
Rui Luo,Yuting Huang,Min Wang,Tong Yu,Kexin Tai,Lin Hu,Xiankun Wu
Advanced oxidation processes based on persulfate (PS-AOPs) have emerged as effective strategies for environmental remediation, with cobalt-based oxides serving as prominent catalysts for peroxymonosulfate (PMS) activation. In this study, we developed a highly active Co 3 O 4 /Al 2 O 3 catalyst (Co/AA) featuring ultrafine nanoparticles, synthesized via a facile approach using tannic acid (TA) as a coordinating agent and activated alumina as a robust support. Co/AA-0.1, as the representative catalyst, was characterized and exhibited outstanding performance in degrading rhodamine B (RB) via PMS activation. Our findings highlight TA's critical role in reducing Co 3 O 4 nanoparticle size, thereby increasing the availability of active sites. The degradation mechanism was elucidated through reactive oxygen species (ROS) quenching experiments and electron paramagnetic resonance (EPR) analysis, revealing that sulfate radicals (SO 4 •− ) are the dominant ROS. The high activity of Co/AA-0.1 is confirmed by analyzing X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area and O 2 -temperature programmed desorption data of the samples. We also investigate the effects of various factors, such as anions, reaction temperatures, and PMS dosage, on RB degradation. Higher temperatures for treating the catalyst are found to reduce activity but improve stability. Notably, the catalyst synthesized through EDTA-assisted synthesis showed balanced activity and stability. Furthermore, the versatility of our synthesis method was demonstrated by successfully applying it to other supports, such as SiO 2 and TiO 2 , offering the development of more efficient and stable catalysts for environmental applications.
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CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yufan Mo,Chunli Li,Huiyu Li,Luis Alberto Estudillo-Wong,Luming Wu,Yinbin Wang,Haibin Yu,Dianqing Li,Yongjun Feng
Porous spherical γ-alumina supports play the key role in the petroleum reforming industry with strict requirement in hydrothermal stability of pore structure. Here, a series of pseudo-boehmite samples with different crystal orientations were synthesized in a separate nucleation and aging steps method by adjusting the rotating speed. The pseudo-boehmite (PB-1000) at 1000 rpm yields a high (0 2 0) plane proportion of 44.52 %, which is comparable with that of 43.91 % for the Sasol Boehmite (SB) powder. The Al 2 O 3 -1000 from the PB-1000 demonstrated the highest content of γ-Al 2 O 3 phase, the lowest surface hydroxyl number of 1.56/nm 2 , and the highest hydrothermal stability with the retention rate of 75.0 % (174 m 2 ·g −1 ) at 600 °C under water vapor for 120 h, which is comparable to that of 72.3 % (191 m 2 ·g −1 ) for the Sasol sample. It is the first time to investigate hydrothermal stability of alumina from the content of γ-Al 2 O 3 phase and the surface hydroxyl groups.
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