查找使用阿拉丁产品的科研文献

Stepwise assembly of multidimensional Al–Pb based coordination polymers

San-Tai Wang,Wei-Hui Fang,Shu-Hua Zhang

The coordination chemistry of the main group elements has always been attractive. Present herein is a stepwise assembly approach toward multidimensional Al–Pb based crystalline compounds. [Al 2 Pb 3 (L) 2 (HL) 2 (μ 3 −OH) 2 ]·2Hdma·2H 2 O·2Cl (AlOC-48) and [AlPb 2 (L) 2 (μ 3 −OH)]·3H 2 O (AlOC-49) (H 3 L ​= ​2,3-dihydroxybenzoic acid, Cat ​= ​catechol and dma ​= ​dimethylamine) represent the first examples of multidimensional Al–Pb based compounds. They are assembled through [Al 4 (L) 4 (Cat) 2 ]] 4- (Al 4 , AlOC-13) polyanions and Pb ions. During the process of coordination assembly, metal site substitution occurs on the Al 4 precursors and transform into Al 2 Pb 2 unit. AlOC-48 and AlOC-49 are two-dimensional and three-dimensional frameworks based on Al 2 Pb 2 clusters. Moreover, the optical band gap and photocurrent response of these two compounds are studied.

A Polyurethane Organic Framework for Flexible Al–Air Batteries

Songmao Zhang,Yichun Wang,Yawen Li,Manhui Wei,Keliang Wang

Flexible Al–air batteries with hydrogels are regarded as a promising power source owing to their high specific capacity, their high ionic conductivity, and having no leakage. However, the mechanical properties of the hydrogels remain unresolved. Here, we present a polyurethane organic framework (POF) employing a polyurethane skeleton as an internal support for poly(acrylic acid) (PAA) hydrogel, where the POF can exhibit high strength and toughness, and an Al–air battery using the POF can output good electrochemical properties. The results demonstrate that the tensile stress of 30 ppi POF is 49.5 kPa owing to the stress-transfer mechanism, while that of PAA is only 3.1 kPa. Compared to that of the PAA hydrogel, the discharging capacity of Al–air batteries with 20 ppi POF can be increased by 79 mAh cm–2 at a current density of 1 mA cm–2, which can be attributed to corrosion inhibition and the surface roughness change of the POF during the discharging process. This work will deliver a selectable strategy for a trade-off between mechanical and electrochemical properties.

Laser emission from flash ignition of Zr/Al nanoparticles

Fan Yang,Xiaoli Kang,Jiangshan Luo,Laixi Sun,Handing Xia,Zao Yi,Yongjian Tang

We report the first laser emission from flash ignition of Zr/Al nanoparticles with the addition of strong oxidizer KClO4 using Nd: YAG as a laser medium. The mixture Zr/Al/Kp-45 (mass ratio = 33%Zr: 33%Al: 34%KClO4) has the highest brightness temperature Tb = 4615 K and the adiabatic flame temperature Tf = 4194 K with the duration of 20 ms. At 1064 nm we measured a maximum output energy of 702.5 mJ with the duration of nearly 10 ms by using only 100 mg mixture with an output coupler (transmission T = 10%). Further optimizing the concentration cavity and increasing the mixture content will yield much higher efficiency and output energy.

Highly reactive Al–Cr2O3 coating for electric-explosion applications

Daixiong Zhang,Qing Xiang,Xueming Li

As a nanoenergetic material with high energy density, nanothermite coatings composed of metal and oxidant have potential applications in electric-explosion devices. In this study, a novel highly reactive Al–Cr2O3 coating was successfully fabricated via electrophoretic deposition (EPD) technology. Moreover, with the advantage of high fabrication rate by employing high concentration of Al and Cr2O3 nanoparticles, an electric-explosion device with successful explosion could be easily obtained via assembling an Al–Cr2O3 coating onto Cu electric-explosion bridges in only 1 minute, which is much more efficient than other coating technologies. More importantly, considering the successful preparation of other reactive coatings in previous work, we also believe that EPD is a promising general strategy for rapidly preparing electric-explosion device with many other nanoenergetic material coatings such as nanothermite and bimetallic reactive composites.

Microstructured Al/Fe2O3/Nitrocellulose Energetic Fibers Realized by Electrospinning

Rui Li,Hongmei Xu,Hailong Hu,Guangcheng Yang,Jun Wang,Jinpeng Shen

Promoted CF4 Decomposition via Enhanced Tricoordinated Al Active Sites

Xiaojian Wang,Hang Zhang,Yingkang Chen,Jialin Zheng,Heping Chen,Kang Liu,Junwei Fu,Zhang Lin,Liyuan Chai,Min Liu

Tetrafluoromethane (CF4), as a typical perfluorocarbon (PFC), has a remarkable global warming potential (GWP) of 7390 and an ultralong lifetime of 50 000 years, making its effective treatment crucial for mitigating environmental impact. Catalytic hydrolysis is a promising way for its effective decomposition, in which Al-based materials have been widely used as efficient catalysts. However, the deficiency of strong Lewis acidic-tricoordinated Al (AlIII) sites strongly limits their catalytic performance. In this work, efficient CF4 decomposition was achieved via promoting AlIII sites over ZnAl2O4 through a facile acid treatment strategy. Among various acid treatments, it was found that H2SO4 treated ZnAl2O4 could achieve 100% CF4 decomposition under a relatively low temperature of 600 °C and kept above 70% removal for over 160 h running. The 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectra demonstrated that the proportion of AlIII was increased from ∼0% of the pristine one to 7.5% after H2SO4 treatment. Pyridine-infrared (Py-IR) spectroscopy and NH3 temperature-programmed desorption (NH3-TPD) and CF4-TPD tests indicated that the amount of acid sites and the adsorption capacity of CF4 were dramatically improved after acid treatment. This work proposes a new strategy to improve CF4 decomposition.

Preparation of Morphologically and Dimensionally Controlled MIL-53(Al)

Chen Lin,Zhang Hang,Fouad Hassan,Akhtar M. S.,Wang Zhihong

This study presents a straightforward hydrothermal synthesis technique for modifying the crystal size and shape of MIL-53(Al) via the use of a mixed solvent solution consisting of water and DMF. Without the use of coordination inhibitors or surfactants, a sequence of nanosized MIL-53(Al) crystals was efficiently synthesized. The lowest crystal size we were able to achieve in this work was 100 nm, but present technologies are not suited to creating nanoscale crystals of this size. Large crystallinity and yield were attained, and the samples’ very large specific surface areas expanded the usefulness of this MOF material for gas adsorption and storage. X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, nitrogen gas adsorption/desorption, and infrared spectroscopy were all used to characterize the samples. Finally, the effect of moisture concentration on crystal size and shape was investigated.

Synthesis of porous Al doped ZnO nanosheets with high adsorption and photodecolorizative activity and the key role of Al doping for methyl orange removal

Xiaohua Sun,Weilong Luo,Linlin Chen,Linjie Zheng,Chao Bao,Panpan Sun,Niu Huang,Yihua Sun,Liang Fang,Lei Wang

Porous Al doped ZnO (AZO) nanosheets have been prepared as an efficient multifunctional water treatment material. Their fundamental properties were characterized by various spectroscopic testing methods. The AZO nanosheets displayed very rapid adsorption rate and high adsorption capacity for methyl orange (MO) dye. The kinetics and equilibrium of adsorption process were found to follow the pseudo-second-order kinetic and Langmuir isotherm models, respectively. Furthermore, the AZO nanosheets exhibited superior photodecolorizative activity compared with the commercial P25 TiO2 nanoparticles. It was found that Al doping increased the zeta potential of AZO nanosheets and then significantly enhanced the adsorption capacity for MO dye and, at the same time, retarded the recombination of photoexcited electron–hole pairs, and prolonged the lifetime of the photo-generated carriers, and then improved the semiconductor photocatalytic activity. In addition, the visible-light-driven dye photosensitized degradation was also an important reason for enhanced photodecolorizative activity. Therefore, AZO nanosheets are a potential multifunctional water treatment material combining highly efficient adsorption and photocatalytic degradation.

The Effect of Annealing on Electrochemical Performances of an Al–Sn–Ga–Mg Alloy as an Anode for Al–air Batteries in Alkaline Electrolytes

Zhaohui Han,Yang Xu,Shenggang Zhou,Lei Xu,Peixian Zhu

In this study, an Al-0.08Sn-0.08Ga-0.5Mg alloy was annealed at 200 °C–400 °C for 10 h. The microstructure and corrosion morphology of the Al anode were observed by scanning electron microscopy (SEM), and the effects of different annealing temperatures on the electrochemical properties of the Al anodes were studied by the hydrogen evolution rate, open circuit potential, Tafel curves, EIS and constant current discharge. The results show that the annealing treatment had a certain effect on the number and size of precipitates on the alloy surface, which improved the electrochemical activity and corrosion resistance of the Al alloy. Additionally, the Al–Sn–Ga–Mg alloy anode material has an excellent discharge performance in the actual use process when the annealing temperature is 350 °C, the related performance parameters were greatly improved compared with other annealing temperature conditions. The capacity density is 2670.99 mAh·g−1, and the energy density is 3379.15 mWh·g−1.

Electrochemical Performance of Al-1Zn-0.1In-0.1Sn-0.5Mg-xMn (x = 0, 0.1, 0.2, 0.3) Alloys Used as the Anode of an Al-Air Battery

Wenfeng Zhang,Tongrui Hu,Tao Chen,Xiaowei Yang,Yunfeng Zhu,Tainian Yang,Liquan Li

In this work, Al-1Zn-0.1In-0.1Sn-0.5Mg-xMn (x = 0, 0.1, 0.2, 0.3) alloys are prepared and used as the anode of an Al-air battery (AAB). We use scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and optical microscopy (OM) to analyze the microstructures of the alloys. The hydrogen evolution rate, electrochemical performance (including polarization curves), electrochemical impedance spectroscopy (EIS), and battery performance of the samples are examined in the 4 M NaOH electrolyte. The experimental data display that the average grain size is significantly refined after adding manganese into the Al-1Zn-0.1In-0.1Sn-0.5Mg alloy, with a decrease in grain size from over 100 μm to about 10 μm. The improved activity of the aluminum anode in the AAB can be attributed to the introduction of manganese. The Al-1Zn-0.1In-0.1Sn-0.5Mg-0.1Mn alloy possesses the optimal overall performance with a lower self-corrosion rate (0.128 mL∙cm−2∙min−1), the highest working potential (1.630 V) and energy density (2415 mWh·g−1), a higher capacity (1481 mAh·g−1) and anodic utilization (49.75%).Keywords:aluminum alloy;aluminum-air battery;self-corrosion;grain size;electrochemical performance

High-performance Al-doped Cu/ZnO catalysts for CO2 hydrogenation to methanol: MIL-53(Al) source-enabled oxygen vacancy engineering and related promoting mechanisms

Guiming Xie,Xingyang Bai,Yi Man,Pengju Ren,Rongrong Jin,Runduo Zhang,Kostya (Ken) Ostrikov,Zhou-jun Wang,Qingyuan Yang

Innovative catalyst design and in-depth mechanism understanding are imperative for industrialization of CO 2 hydrogenation to methanol. Herein, Al-doped Cu/ZnO catalysts, Cu/Al-ZnO-x (x = 1/32, 1/16 and 1/8, denoting Al/Zn molar ratio), were creatively synthesized using MIL-53(Al) as Al sources and reactive templates. The Cu/Al-ZnO-1/16 catalyst exhibited the highest methanol production rate among the Cu/Al-ZnO-x catalysts, which was 1.93 times as active as the conventional Cu/Al-ZnO-1/16-C catalyst using Al(NO 3 ) 3 ·9H 2 O as Al source. Structural characterizations reveal that the use of MIL-53(Al) led to higher S BET , more uniform Al distribution, more abundant oxygen vacancies, more appropriate metal-support interactions and larger amount of medium basic sites. Mechanism studies demonstrate that Al doping would markedly induce oxygen vacancy formation on Cu-ZnO interfaces and thus significantly boost methanol synthesis activity. This work offers a facile approach to develop efficient methanol synthesis catalysts and provides new insights into the nature of Al promotion in Cu/ZnO-based catalysts.

Mechanism of transmethylation in anisole decomposition over HZSM-5: Experimental study

Jiajun Zhang,Beatriz Fidalgo,Dekui Shen,Rui Xiao,Sai Gu

This work investigated the decomposition of anisole (methoxyl-based lignin model compound) in a fluidized bed reactor over no catalysts and a series of HZSM-5 zeolite catalysts with different Si/Al atomic ratios. Transmethylation reaction was identified as the initial step of the thermal decomposition of anisole, leading to the prominent production of phenolic compounds. Methyl phenols were identified as the main products, with the yield of o -cresol being higher than that of p-cresol at the temperatures below 600°   C. The transmethylation reaction over HZSM-5 zeolite catalyst was found to occur at temperatures 150°   C lower than those for non-catalytic reaction, with the yield of the phenolic compounds being promoted by 2.5 times. Production of the main phenolic compounds during the catalytic decomposition of anisole was enhanced to different extents depending on the Si/Al ratio. The highest selectivity of 79   wt.% was achieved over the zeolite catalyst with a Si/Al ratio of 80. The Brønsted acid sites of the catalyst played a significant role in both the preferential formation of phenolic compounds and preservation of the methyl group.