International Journal of Applied Ceramic Technology
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2019
·Vol. 17
·期 2
·778-789
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IF 1.074
Weihua Chen,Jiancheng Tang,Xingwang Shi,Nan Ye,Zhihao Yue,Xinghao Lin
High-purity titanium aluminum carbide (Ti 3 AlC 2 ) powders were synthesized by a microwave sintering method using different titanium sources as raw materials. The prepared products were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the synthesized Ti 3 AlC 2 powders have high purity (97.5%) and even distribution of the grain size when using a 3TiH 2 /1.2Al/2C mixture as raw materials when the microwave sintering temperature and time were 1300°C and 30 minutes, respectively. The formation mechanism of the Ti 3 AlC 2 is described as proceeding via four stages. The solid-phase reaction between titanium and aluminum occurs below the melting point of aluminum and the main product is a Ti 3 Al phase, which is an observed intermediate compound for the formation of Ti 2 AlC and Ti 3 AlC 2 . Thus, this study provides a beneficial approach to low-temperature synthesis of high-purity Ti 3 AlC 2 materials.
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JOURNAL OF POWER SOURCES
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2020
·
IF 8.247
Yangyang Luo,Chenhui Yang,Yapeng Tian,Yi Tang,Xingtian Yin,Wenxiu Que
To enhance rate and cycle performances of nickel sulfide, the two-dimensional (2D) titanium carbide (Ti 3 C 2 , MXene) with good electrical conductivity and electrochemical stability is chosen as 2D supporting matrix for synthesizing nickel sulfide/delaminated Ti 3 C 2 (Ni–S/d-Ti 3 C 2 ) nanohybrids by a solvothermal method . The Ni–S/d-Ti 3 C 2 nanohybrids show a coexistence of Ni 3 S 2 and NiS with the characteristic peak of d-Ti 3 C 2 nanosheets , and have electroactive species-on-sheet structures. The optimal Ni–S/1d-Ti 3 C 2 nanohybrid delivers a high specific capacity of 840.4 C g −1 at 1 A g −1 with enhanced capacity retention of 64.3% at 30 A g −1 and an outstanding cycle performance, which are ascribed to an integration of d-Ti 3 C 2 nanosheets that can act as electric channels to accelerate electrons transport at interface of the nanohybrid during charge-discharge processes. An increased Ni 2+ content and BET surface area also contribute to redox reactions of Ni–S/1d-Ti 3 C 2 nanohybrid electrode. An asymmetric supercapacitor (ASC) fabricated by using the Ni–S/1d-Ti 3 C 2 nanohybrid as positive electrode and d-Ti 3 C 2 film as negative electrode exhibits an energy density of 20.0 Wh kg −1 at 0.5 kW kg −1 and a good cycling stability. Our work provides a favorable ingenuity for synthesizing advanced nickel sulfide-based nanohybrids and an alternative strategy of using 2D MXene as capacitive electrode for high-performance supercapacitors .
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JOURNAL OF AOAC INTERNATIONAL
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2019
·Vol. 98
·期 1
·225-229
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IF 1.201
Zhang Jing,Yong Xiaojing,Zhao Dongyan,Shi Qiuyi
The content of mononuclear Al (Ala%) changed with its determination time (ta) under different dosages of Ferron (7-iodo-8-hydroxyquinoline-5-sulfonic acid, [Ferron]), and the change of Ala% with [Ferron] at different ta was systematically investigated for the firsttime. Thus, the most appropriate ta was found with the optimal [Ferron]. Also, the judgment of the platform (flat or level portion) of the complete reaction on the absorption-time curve determined in the hydroxyl polyaluminum solution by Ferron timed spectrophotometry (Ferron assay) was first digitized. The time point (tb) of complete reaction between the medium polyaluminum (Alb)and Ferron reagent depended on the reaction extent, and time could not be used only to judge. Thus, the tb was accurately determined and reduced
to half of original, which improved the experiment efficiency significantly. The Ferron assay was completely optimized.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Handong Jiao,Shuqiang Jiao,Shijie Li,Wei-Li Song,Haosen Chen,Jiguo Tu,Mingyong Wang,Donghua Tian,Daining Fang
Although rechargeable Al batteries attract interests due to their features of abundant Al source and high safety, the Al negative electrodes suffer from critical problems, including dendrite, corrosion, pulverization, non-recyclable Al wastes, etc. For addressing these challenges, here a novel liquid gallium is demonstrated for negative electrodes of Al batteries. The results show that the liquid gallium negative electrode enables the reversible alloying/dealloying between Al and Ga. Remarkably, the essential problems in the solid Al negative electrodes, including dendrite, corrosion and pulverization, would be well avoided attributed to the liquid state of the Ga electrode during cycling. In addition to the enhanced stable cycling performance, Ga negative electrode is also recyclable, allowing the cycled Ga for further presenting stable cycling in the re-assembled batteries, and which is helpful for its practical application. The results in the present work open a precedent way to develop the advanced negative electrode with dendrite-free, corrosion resistant and recyclable features and advantages for various types of rechargeable batteries.
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Catalysts
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2019
·Vol. 9
·期 11
·944
·
IF 3.444
Jun Zhou,Yue Zhang,Song Li,Jing Chen
Heterogeneous catalysis often involves charge transfer between adsorbed molecules and the surface of catalyst, and thus their activity depends on the surface charge density. The efficiency of charge transfer could be optimized by adjusting the concentration of oxygen vacancies (Ov). In this work, hexagonal Ni(OH)2nanoparticles were initially synthesized by a hydrothermal process using aluminum powder as the sacrificial agent, and were then converted into 2D Ni/NiO nanocomposites through in situ reduction in hydrogen flow. The oxygen vacancy concentration in the NiO nanosheet could be well-controlled by adjusting the reduction temperature. This resulted in strikingly high activities for hydrogenation of nitrophenol. The Ni/NiO nanocomposite could easily be recovered by a magnetic field for reuse. The present finding is beneficial for producing better hydrogenation catalysts and paves the way for the design of highly efficient catalysts.Keywords:metal-oxide interaction;oxygen vacancy;hydrogenation;catalyst
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Materials Research Express
·
2019
·Vol. 6
·期 4
·045207
·
IF 1.449
Jing Liu,Yunzhu Ma,Wensheng Liu,Xiaolei Song,Shuwei Yao,Juan Wang,Ming Cheng,Chunlan Li
Precursor sol with a high solid content is significant for alumina fiber synthesis. In the present work, alumina precursor sols used for preparing alumina fibers were synthesized by dissolving aluminum powder (AP) into a mixture of formic acid, acetic acid and deionized water. The effects of preparation temperatures on solubility of AP, structure of the synthesized sols and gels were investigated. The reaction mechanism of hydrolysis and polymerization was also studied. Based on the reaction mechanism, alumina precursor sol with a high solid content was acquired through the adjustment of temperature. The results revealed that all the sols synthesized at the temperature from 85 °C to 115 °C consisted of polymers, linear oligomers and monomeric species. Colloidal particles presented spherical shape with a uniform size. However, AP cannot dissolve entirely at 85 °C and white precipitates (HO)Al(CH3COO)2 was produced at 105 °C and 115 °C. AP had the highest dissolution degree at 95 °C. A colorless and transparent alumina sol with the highest solid content was acquired at this temperature. The structure of concentrated gels was also discussed. It was revealed that network polymers increased when using sols synthesized at temperature above 105 °C, which were negative for spinning. Continuous green fibers were obtained successfully using the alumina sol prepared at 95 °C.
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Junfang Ding,Liping Li,Haorui Zheng,Ying Zuo,Xiyang Wang,Huixia Li,Shaoqing Chen,Dan Zhang,Xingliang Xu,Guangshe Li
Nanomaterials are widely used as redox-type reaction catalysts, while reactant adsorption and O2 activation are hardly to be promoted simultaneously, restricting their applications in many important catalytic fields such as preferential CO oxidation (CO-PROX) in H2-rich stream. In this work, an interface-enhanced Co3O4–CuCoO2 nanomesh was initially synthesized by a hydrothermal process using aluminum powder as a sacrificial agent. This nanomesh is systematically characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption, X-ray photoelectron spectroscopy, UV–vis absorption spectroscopy, Raman spectroscopy, X-ray absorption near-edge spectroscopy, hydrogen temperature-programmed reduction, and oxygen temperature-programmed desorption. It is demonstrated that the nanomesh possesses high-density nanopores, enabling a large number of CO adsorption sites exposed to the surface. Meanwhile, electron transfer from O2– to Co3+/Co2+ and the weakened bonding strength of Co–O bond at surfaces promoted the oxygen activation and redox ability of Co3O4. When tested as a catalyst for CO-PROX, this nanomesh with an optimized pore structure and a surface electronic structure, exhibits a strikingly high catalytic oxidation activity at low temperatures as well as a broader operation temperature window (i.e., CO conversion >99.0%, 100–200 °C) in the CO selective oxidation reaction. The present finding should be highly useful in promoting the quest for better CO-PROX catalysts, a hot topic for proton exchange membrane fuel cells and automotive vehicles.
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高影响因子
Materials
·
2019
·Vol. 12
·期 2
·234
·
IF 2.972
Xiaogang Guo,Taotao Liang
In this study, a novel superhydrophobic nano-aluminum/iron (III) oxide composite has been prepared by a facile one-step process of electrophoretic deposition, with wide potential applications. The optimal suspension included ethanol, acetyl-acetone, and the additives of fluorotriphenylsilane and perfluorodecyltriethoxysilane. The microstructure, wettability, and exothermic performance were analyzed by field emission scanning electron microcopy (FESEM), X-ray diffraction (XRD), water contact angle measurements, and the differential scanning calorimetry (DSC) technique. The water contact angle and the heat-release of the target composites could reach to ~170° and 2.67 kJ/g, and could still keep stable, after exposure for six months, showing a great stability. These results provided an exquisite synthesis of ideas, for designing other superhydrophobic energetic materials with self-cleaning properties, for real industrial application.Keywords:aluminum/iron (III) oxide;electrophoretic deposition;perfluorodecyltriethoxysilane;self-cleaning;great stability
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高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 10
·5635-5642
·
IF 10.733
Lin Yang,Yohan Dall'Agnese,Kanit Hantanasirisakul,Christopher E. Shuck,Kathleen Maleski,Mohamed Alhabeb,Gang Chen,Yu Gao,Yoshitaka Sanehira,Ajay Kumar Jena,Liang Shen,Chunxiang Dall'Agnese,Xiao-Feng Wang,Yury Gogotsi,Tsutomu Miyasaka
MXenes, a class of two-dimensional (2D) transition metal carbides and nitrides, have a wide range of potential applications due to their unique electronic, optical, plasmonic, and other properties. Herein, we explore the use of the Ti3C2 MXene in organic–inorganic lead halide perovskite solar cells (PSCs). SnO2–Ti3C2 MXene nanocomposites with different contents of Ti3C2 (0, 0.5, 1.0, 2.0, and 2.5 wt‰) were used as electron transport layers (ETLs) in low-temperature processed planar-structured PSCs. Mixing SnO2 with 1.0 wt‰ Ti3C2 effectively increases the power conversion efficiency (PCE) from 17.23% to 18.34%, whereas the device prepared with pristine Ti3C2 as the ETL achieves a PCE of 5.28%. Photoluminescence and electrochemical impedance spectroscopy results reveal that metallic Ti3C2 MXene nanosheets provide superior charge transfer paths, enhancing electron extraction, electron mobility, and decreasing the electron transfer resistance at the ETL/perovskite interface, and thus leading to higher photocurrents. This work proposes a new field of application for MXenes and a promising method to increase the efficiency of solar cells.
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VACUUM
·
2019
·
IF 2.515
Yanjun Yin,Xueming Li
This study focus on the combustion performance and energy released of self-propagating Al/CuO nanothermite with nanorod structure comprehensively. CuO nanorods with lengths of 50 nm–100 nm were synthesized in large scale by template-free hydrothermal method . Al/CuO nanothermite coatings were further built successfully by co-deposition of the as-prepared CuO nanorods and nano-Al via electrophoretic deposition (EPD). Additionally, the EPD kinetic behavior of CuO nanorods and Al/CuO composites is investigated comprehensively. The optimum deposition time is 15 min and the composites is much homogenous when equivalence ratio (Ф) of Al and CuO is 0.75. Furthermore, the onset temperature is down to 315 °C and the energy release is approximately 3043 J/g along with rapid and violent combustion performance in the thermite reaction of Al/CuO nanorods. It is speculated that the excellent properties of the Al/CuO nanothermite could be ascribed to the uniform distributing and intimate interfacial contact between nano-Al and CuO nanorods.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Zizheng Ai,Yongliang Shao,Bin Chang,Lei Zhang,Jianxing Shen,Yongzhong Wu,Baibiao Huang,Xiaopeng Hao
As a metal-free polymeric semiconductor, graphitic carbon nitride (g-C 3 N 4 ) is a promising candidate for photocatalytic water splitting but suffers from the insufficient optical absorption and sluggish utilization of photocarriers. Herein, based on the energy band engineering theory, a new design philosophy of tunable p-n homojunction is proposed and realized in a novel P-doped g-C 3 N 4 (PCN) material. Through regulating the tendency of transformation in p-n homojunction, a strong internal electric field is built and integrated with two secondary internal electric fields by further decorating with Ti 3 C 2 , leading to the formation of a triple-internal electric field system. Thus the spatial separation efficiency of photocarriers is improved and their lifetime is prolonged. The specific photocatalyst exhibits excellent overall water splitting performance in pure water with a notable quantum yield. This work presents a peculiar concept of adjustable p-n homojunction and holds great significance for the rational design of advanced photocatalyst in water splitting.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Tao Yan,Hui Ren,Jie Liu,Qingjie Jiao
To improve reaction rate of energetic materials, electrospray technology was applied to develop microspheres in which recrystallized cyclotrimethylene trinitramine (RDX) was integrated with nano-Al (nAl) particles and Viton through a two-solvent strategy. Results on morphology properties and chemical heterogeneity demonstrated that the electrosprayed microspheres were hollow spheres containing well-dispersed RDX . It was suggested that RDX nano-crystals adhere tightly on both sides of the nAl@Viton skeletons, thereby increasing the contact area among components. The thermal analysis of the microspheres indicated that nAl particles accelerated the energy release by decreasing the apparent activation energy for microsphere decomposition. Experimental results showed that electrosprayed nAl@RDX@Viton had shorter laser ignition delay and more vigorous combustion flame than the physical mixture, which benefitted from the characteristic structure and synergistic effects of the components.
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