JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2019
·
IF 5.04
Xuan Liu,Jilai Xue,Zhichao Guo,Cheng Zhang
This work mainly deals with the segregating behaviors of Sc and the growth of unique primary Al 3 Sc in Al-Sc alloys prepared by molten salt electrolysis. The alloys contain 0.23–1.38 wt%Sc where Sc segregation is observed. It is found that a high current density and long electrolysis time are in favor of high Sc content, and so do the high temperature and the addition level of Sc 2 O 3 . Sc content at the edge of Al based alloy (average Sc content: 0.75 wt%) can be as high as 1.09 wt%, while it is merely 0.24 wt% at the central area. The cooling rates have a strong impact on the morphology and particle size of primary Al 3 Sc, but a weak influence on Sc segregation. The cusped cubic and dendritic primary Al 3 Sc can precipitate in the prepared Al-Sc alloys. In a slightly hypereutectic Al-0.67 wt%Sc alloy, a large and cusped dendrite grows from the edge into the center. The primary and secondary dendritic arms can be as long as 600 and 250 μm, respectively. The Sc segregating behaviors in Al-Sc alloys is due to the mechanism controlled by the limited diffusion rate of Sc in liquid Al. This can involve the establishment of a near spherical discharge interface between liquid Al and the electrolyte. The Sc rich layer near Al-molten salt interface may provide the potential primary nuclei and sufficient Sc atoms for the growth of large dendritic primary Al 3 Sc.
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高影响因子
FUEL
·
2019
·
IF 5.128
Xiangping Li,Jianguang Zhang,Bin Liu,Juping Liu,Chuanbin Wang,Guanyi Chen
Non-noble metal(s)-based mesoporous catalysts are one of the promising catalysts for aqueous phase hydrodeoxygenation of lignin-derived phenols to produce hydrocarbons. In this paper, Ni/Al-SBA-15 was prepared through incipient wetness impregnation method and the performance of eugenol hydrodeoxygenation over Ni/Al-SBA-15 was studied. The effect of incipient wetness impregnant on the performance of eugenol hydrodeoxygenation over Ni/Al-SBA-15 was investigated. The materials were characterized by XRD, N 2 -sorption, TEM, FTIR, Py-FTIR, XRF and ICP-MS. In comparison with the traditional incipient wetness impregnation using water as solvent, the activity of Ni/Al-SBA-15 was significantly improved by using ethanol as solvent during the process of incipient wetness impregnation. For Ni/Al-SBA-15, the quantity of total acid was decreased after loading nickel species which was mainly due to the decrease of Lewis acid sites. The strength of Lewis acid in Ni/Al-SBA-15 prepare with ethanol as impregant was enhanced. The yields of propyl cyclohexane and propylbenzene from aqueous phase hydrodeoxygeation of eugenol over Ni/Al-SBA-15-E were increased. The super catalytic behavior of Ni/Al-SBA-15-E was attributed to the synergistic effect between the stronger Lewis acid sites and the intact framework structure of Ni/Al-SBA-15-E.
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高影响因子
COMBUSTION AND FLAME
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2019
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IF 4.12
Jun Wang,Yanyang Qu,Feiyan Gong,Jinpeng Shen,Long Zhang
Aluminum based energetic nanomaterials attract significant attention for various applications owing to their ultrahigh energy density . The main obstacle in the application of nano-Al based energetic materials is the slow combustion reaction kinetics and reduced energy output resulting from the inert Al 2 O 3 shell. In this paper, an efficient surface self-activation strategy is proposed to significantly improve the combustion performance and energy output of nano-Al based energetic materials. A porous AlF 3 shell is formed on the surface of the nano-Al particle by an etching reaction between perfluorododecanoic acid and the Al 2 O 3 dense layer. The porous AlF 3 shell provides a new reaction channel for the reaction of Al and the oxidizer , thus significantly improving the energy output and combustion reaction kinetics. The energy output and combustion reaction speed of polytetrafluoroethylene (PTFE)/nano-Al coated with C 11 F 23 COOH are 6304 J/g and 670 m/s, which are 3.0 and 2.6 times higher than those of PTFE/nano-Al, respectively. The mechanism of the self-activating process is proposed to explain the enhanced combustion reaction kinetics and energy output of the nano-Al based energetic materials. The proposed surface self-activation strategy for nano-Al particles can efficiently to enhance the reactivity and energy output and promote the development of the nano-Al based energetic materials.
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高影响因子
RSC Advances
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2019
·Vol. 9
·期 44
·25266-25273
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IF 3.049
Jiaxing Song,Tao Guo,Wen Ding,Miao Yao,Fengli Bei,Xiaonan Zhang,Junyi Huang,Xiang Fang
To explore the effect of the addition of poly(vinylidene fluorine) (PVDF) to a nanothermite system, an Al/MnO2/PVDF energetic nanocomposite was prepared using an electrospray method, Al/MnO2 nanothermite was prepared as a control group. Then, the energetic nanocomposite and nanothermite were tested and analyzed by XRD, FE-SEM and TG-DSC, and the reaction products were collected. The results show that energetic nanocomposite would have three obvious exothermic peaks in the range of room temperature to 800 °C with a total more than 1700 J g−1 heat release while the control experiment, Al/MnO2 nanothermite, could be found one exothermic peak with a 1100 J g−1 heat release. The residues are mainly MnAl2O4, MnF2 and AlF3 which indicates that Al/MnO2/PVDF energetic nanocomposite could make full use of manganese oxide. Finally, thermal analysis experiments were carried out under different heating rates to calculate the activation energy. The calculation results show that the addition of PVDF could significantly reduce the activation energy, which would help spark the thermite at comparatively low energy and temperature.
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PubMed
高影响因子
Journal of Environmental Sciences
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2019
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IF 3.556
Xuejun Xiong,Hui Xu,Beiping Zhang,Xiaohui Wu,Hongyan Sun,Dongsheng Wang,Zhengyang Wang
Membrane filtration combined with pre-coagulation has advantages in advanced wastewater treatment . As a model of a microbial polysaccharide , research on the effect of sodium alginate (SA) on alum hydrolysis has been rare; therefore, it is necessary to gain insight into the interface interaction between SA molecules and Al species, and the role SA plays during floc formation. In this study, the interaction mechanism between SA and Al species has been investigated, by evaluating the effect of SA on floc characteristics and membrane fouling during coagulation–ultrafiltration with different Al species coagulants (AlCl 3 and preformed Al 13 ). Al 2p X-ray photoelectron spectroscopy (XPS) confirmed that the complexation of ligands and Al species strongly affects the reaction pathways for Al hydrolysis and the final nature of the flocs, as Al 13 can be decomposed into octahedral precipitates when SA is added. The presence of SA can affect floc properties, which have important impacts on the characteristics of the cake layer and membrane fouling. Due to the bridging ability of SA, the floc strength increased by about 50% using Al a , which was much better than preformed Al 13 , with a percentage increase of only about 6%. Moreover, the recovery factor of HA-flocs was decreased from 96% to 43% with SA addition of 0.5 mg/L. It was concluded that SA can affect the characteristics of the cake layer and membrane fouling through participating in the formation of primary flocs and altering the Al hydrolysis pathway.
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PubMed
高影响因子
Journal of Cleaner Production
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2019
·
IF 6.395
Yutao Peng,Yuqing Sun,Runze Sun,Yaoyu Zhou,Daniel C.W. Tsang,Qing Chen
Highly efficient and cost-effective adsorbents for phosphate (P) recovery are the key to control eutrophication and recover phosphorous from waste streams to enhance food production . This study assembled waste biomass (corn stalk, almond shell, and dairy manure)-derived biochars with Fe/Al (hydr)oxides through co-precipitation method. The fabricated biochar composites presented excellent performance for the adsorption of P due to good amounts of surface area, pore volume, and reactive surface hydroxyl sites. Response surface methodology (RSM) was applied to optimize the production conditions of the Fe–Al (hydr)oxides-biochars for maximizing the P removal. The effects of three key independent variables, i.e. , Fe 3+ concentration (0.2–1.0 mol L −1 ), Al 3+ concentration (0.2–1.0 mol L −1 ), and mass-to-volume ratio (0.05–0.20 g mL −1 ) on the P removal were investigated. The synthesized composites outperformed other sorbents for the P removal, suggesting the synergistic effects of Fe/Al (hydr)oxides and biochar support. These results offer valuable insights to develop high-performance biochar-based composites for green and sustainable environmental remediation.
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TRIBOLOGY LETTERS
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2019
·Vol. 67
·期 3
·1-11
·
IF 2.235
Zeng M. Q.,Hu R. Z.,Song K. Q.,Dai L. Y.,Lu Z. C.
An in situ displacement reaction was used to prepare an Al–12 wt% Sn nanocomposite alloy from mechanically alloyed Al–SnO 2 –MgH 2 . The nanoscaled Sn phase was mostly 30–50 nm in size and was distributed uniformly in the Al matrix. The wear properties of the Al–SnO 2 –MgH 2 composite were enhanced significantly compared to those of an Al–Sn–MgH 2 composite. These improvements stemmed from the high-strength and nanoconfined Sn-phase lubrication, which moved the peak stress far below the surface, released strain localization at the uppermost sliding surface layer, and suppressed cracking and surface roughening. The dispersion strengthening of the Al–SnO 2 –MgH 2 composite favored the maintenance of a stable tribolayer, which resulted in an integrated worn surface and an excellent wear performance.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Xiaoxia Ma,Ying Zhu,Shengxian Cheng,Huanxi Zheng,Yousong Liu,Zhiqiang Qiao,Guangcheng Yang,Kaili Zhang
The limited gas production of Al/metal oxide-based thermites due to lack of gas elements (e.g., C, H, and N) greatly hinders its practical application. By contrast, energetic coordination polymers (ECPs) are rich in gas elements from organic ligands and have the potential to rapidly decompose into corresponding metal oxides with a large amount of heat output. In this work, a novel high-performance energetic material based on Al/ECPs is presented. Al/ECPs binary energetic composites have enhanced heat release, pressure production, and combustion performance owing to the contribution of the “father” ECPs’ thermal decomposition reaction and the “son” metal oxide’s thermite reaction with nano-Al. [Mn(BTO)(H 2 O) 2 ] n (BTO = 1 H ,1′ H -[5,5′-bitetrazole]-1,1′-bis(olate)) is used as a typical ECP and composited with nano-Al. The exothermic peak of the thermite reaction between 520 °C and 730 °C on the differential scanning calorimetry curves contributes to the high heat output of the Al/[Mn(BTO)(H 2 O) 2 ] n energetic composites, especially when the molar ratio of Al/Mn is 1.0 (2189.6 J/g). The peak pressure of this composite (3.6 MPa) is 1.5 times as high as that of traditional nanothermite (Al/CuO) with much longer high-pressure duration in the closed bomb experiments. It also exhibits very intense burning and long duration (around 300 ms) in opening burning experiments. These results prove that the father-son effect of ECPs is highly significant in developing new-concept Al/ECPs energetic materials for gas generation, heat release and combustion.
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高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2018
·Vol. 59
·期 1
·103-111
·
IF 1.551
Ying Gong,Wenying Zhou,Xuezhen Sui,Yujia Kou,Li Xu,Yue Duan,Fuxin Chen,Ying Li,Xiangrong Liu,Huiwu Cai,Qingguo Chen,Zhi-Min Dang
Surface modification of core-shell structured Al (Al@Al 2 O 3 ) nanoparticles was performed using γ -(Aminopropyl)-triethoxysilane (APS) and dopamine (DA), respectively, and the microstructures, dielectric properties and thermal conductivities of the Al/poly(vinylidene fluoride) (PVDF) nanocomposites were investigated. Both DA and APS enhance the interfacial bonding strength between the fillers and the matrix, leading to homogeneous dispersion of Al nanoparticles in PVDF matrix. Compared with raw Al nanoparticles, surface-treated Al/PVDF exhibit much higher dielectric permittivity due to the enhanced interfacial interactions between the two components, whereas, the dielectric loss and electric conductivity of the nanocomposites still remain at rather low levels owing to the insulating alumina shell preventing effectively core Al from direct contact. The dynamic dielectric properties results reveal that dielectric constant and loss increase with temperature due to the gradually enhanced mobility of molecular chain segments of PVDF for the raw Al/PVDF and treated Al/PVDF nanocomposites. Additionally, the PVDF nanocomposites with Al treated with APS and DA show enhanced thermal conductivities compared with raw Al/PVDF under the same filler loading because of reduced thermal interfacial resistance promoting phonon transfer across the interfaces. POLYM. ENG. SCI., 59:103–111, 2019. © 2018 Society of Plastics Engineers
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 102
·期 3
·1414-1424
·
IF 2.956
Yaowu Wei,Tao Zhang,Qi Zhang,Bingqiang Han,Nan Li
Improving the hydration resistance of CaO aggregates is the key to successful application of lime-based refractories in metallurgical industry. Additive Zr(OH) 4 and Al(OH) 3 were introduced in the preparation of CaO granules using granulation equipment and calcination method in this study. The results showed that the hydration resistance of CaO granules was improved significantly, especially for granules with 0.6 wt.% Zr(OH) 4 and 0.9 wt.% Al(OH) 3 , respectively. The shell of CaO granules was relatively dense after calcination and the volume of open pores of CaO granules decreased from 3.56 × 10 −2 to 1.80 × 10 −2 cm 3 /g when additive was introduced. Zr(OH) 4 and Al(OH) 3 have the opposite effect on the closed porosity of CaO granules, the closed porosity of CaO granules was decreased with Zr(OH) 4 addition, but increased with Al(OH) 3 addition.
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高影响因子
Results in Physics
·
2018
·
IF 2.147
Wenqiang Su,Ping Wang,Zhengyang Cai,Junhe Yang,Xianying Wang
Molybdenum disulfide (MoS 2 ) has shown its promising performance for use as an electrocatalyst for hydrogen evolution reaction (HER). However, it has commonly suffered from limited edge active sites and stagnant conductivity in this regard. Therefore in the present work, with integrating graphene aerogel (GA) supporting and Al ions doping, we report for the first time one-pot hydrothermal synthesis of Al-doped MoS 2 @GA aerogel electrocatalysts with 3D porous network architecture. Vertical MoS 2 ultrathin nanosheets with defect-rich structure are grown on graphene nanosheets at the optimum weight ratio of 5 wt% GA, leading to the enhancement of HER activity. Simultaneously Al doping of 0.77 at% further optimizes the number of exposed active sites and conductivity. The overpotential at a current of 10 mA·cm −2 was successfully reduced to 212 mV with a Tafel slope value down to 41 mV/dec, benefiting from synergistically structural and electronic modulating of MoS 2 . The study thus sheds light on designing and developing high-performance 3D network electrocatalysts for HER reaction.
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高影响因子
JOURNAL OF POWER SOURCES
·
2018
·
IF 6.945
Wei Xing,Dongfeng Du,Tonghui Cai,Xiaochen Li,Jin Zhou,Yongming Chai,Qingzhong Xue,Zifeng Yan
Aluminum ion batteries are attractive new generation energy storage devices in large-scale energy applications such as grid storage due to its low cost, high safety and three-electron-redox properties potentially leading to high capacity. Cathode materials with both high capacity and rate performance are urgently needed to fulfill such applications. Here, a three-dimensional carbon-encapsulated cobalt selenide nanoparticles are developed from metal organic frameworks as a novel aluminum ion batteries cathode. The cathode material delivers an unprecedented capacity of 427 mAh g −1 at 1000 mA g −1 with two high discharge plateaus at 1.0 V and 1.9 V (equivalent to energy density of 424 Wh kg −1 ). And even at a very high current density of 5000 mA g −1 , the initial discharge capacity of cathode electrode can reach 254.8 mAh g −1 , and a high capacity of 62.4 mAh g −1 is retained after 100 cycles. Such outstanding performance are attributed to the well-defined nanostructure of three-dimensional carbon-encapsulated cobalt selenide cathode material. This work represents a significant step forward to prepare advanced cathode materials for aluminum ion batteries.
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