scholarly journals Enhanced Hydrogen Generation Performance of Al-Rich Alloys by a Melting-Mechanical Crushing-Ball Milling Method

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7889
Author(s):  
Lixiang Zhu ◽  
Meishuai Zou ◽  
Xiaodong Zhang ◽  
Lichen Zhang ◽  
Xiaoxuan Wang ◽  
...  
Keyword(s):  
Melting Point ◽  
Ball Milling ◽  
Room Temperature ◽  
Hydrogen Generation ◽  
Al Alloys ◽  
X Ray ◽  
H2 Generation ◽  
Milling Method ◽  
Hydrolysis Of ◽  
Mechanical Crushing

The main problem for the application of hydrogen generated via hydrolysis of metal alloys is the low hydrogen generation rate (HGR). In this paper, active Al alloys were prepared using a new coupled method-melting-mechanical crushing-mechanical ball milling method to enhance the HGR at room temperature. This method contains three steps, including the melting of Al, Ga, In, and Sn ingots with low melting alloy blocks and casting into plates, then crushing alloy plate into powders and ball milling with chloride salts such as NiCl2 and CoCl2 were added during the ball milling process. The microstructure and phase compositions of Al alloys and reaction products were investigated via X-ray diffraction and scanning electron microscopy with energy dispersed X-ray spectroscopy. The low-melting-point Ga-In -Sn (GIS) phases contain a large amount of Al can act as a transmission medium for Al, which improves the diffusion of Al to Al/H2O reaction sites. Finer GIS phases after ball milling can further enhance the diffusion of Al and thus enhance the activity of Al alloy. The hydrogen generation performance through hydrolysis of water with Al at room temperature was investigated. The results show that the H2 generation performance of the Al-low-melting point alloy composite powder is significantly higher than the results reported to date. The highest H2 generation rate and H2 conversion efficiency can reach 5337 mL·min−1·g−1 for the hydrolysis of water with 1 g active alloy.

Effect of High-Energy Ball Milling on Microstructure and Microwave Absorbing Properties of NdFe Material

2011 ◽  
Vol 311-313 ◽  
pp. 1281-1285 ◽  
Author(s):  
Pei Hao Lin ◽  
Lei Wang ◽  
Shun Kang Pan ◽  
Hua Mei Wan
Keyword(s):  
Ball Milling ◽  
Particle Morphology ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray ◽  
Microwave Absorbing Properties ◽  
Absorbing Materials ◽  
Milling Method ◽  
Energy Ball ◽  
Microwave Absorbing

The NdFe magnetic absorbing materials were prepared by rapid solidification and high-energy ball milling method. The effect of high-energy ball milling on particle morphology, organizational structure and microwave absorbing properties of NdFe magnetic absorbing materials were analyzed with the aid of X-ray diffractometer, scanning electron microscope and vector network analysis. The results show that the Nd2Fe17 and α-Fe phase are refined, the particles become smaller and thinner; the span-ratio of the particles increases along with time during the process of high-energy ball milling; and meanwhile, the frequency of absorbing peak reduces. The absorbing bandwidth broadens as the increase of the time of ball milling, except that of 48h.The minimum reflectance of the powder decreases from -22dB to - 44dB under the circumstances that the time of high energy ball milling reaches 48h and the thickness of the microwave absorbing coating is 1.5mm. But it rebounds to about - 6dB when the time of ball milling reaches 72h.

scholarly journals Copper Nanowires as Highly Efficient and Recyclable Catalyst for Rapid Hydrogen Generation from Hydrolysis of Sodium Borohydride

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1153 ◽  
Author(s):  
Aina Shasha Hashimi ◽  
Muhammad Amirul Nazhif Mohd Nohan ◽  
Siew Xian Chin ◽  
Poi Sim Khiew ◽  
Sarani Zakaria ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Sodium Borohydride ◽  
Fossil Fuels ◽  
Hydrogen Generation ◽  
Clean Energy ◽  
Catalytic Performance ◽  
Copper Nanowires ◽  
H2 Generation ◽  
Hydrolysis Of ◽  
Hydrolysis Of Nabh4

Hydrogen (H2) is a clean energy carrier which can help to solve environmental issues with the depletion of fossil fuels. Sodium borohydride (NaBH4) is a promising candidate material for solid state hydrogen storage due to its huge hydrogen storage capacity and nontoxicity. However, the hydrolysis of NaBH4 usually requires expensive noble metal catalysts for a high H2 generation rate (HGR). Here, we synthesized high-aspect ratio copper nanowires (CuNWs) using a hydrothermal method and used them as the catalyst for the hydrolysis of NaBH4 to produce H2. The catalytic H2 generation demonstrated that 0.1 ng of CuNWs could achieve the highest volume of H2 gas in 240 min. The as-prepared CuNWs exhibited remarkable catalytic performance: the HGR of this study (2.7 × 1010 mL min−1 g−1) is ~3.27 × 107 times higher than a previous study on a Cu-based catalyst. Furthermore, a low activation energy (Ea) of 42.48 kJ mol−1 was calculated. Next, the retreated CuNWs showed an outstanding and stable performance for five consecutive cycles. Moreover, consistent catalytic activity was observed when the same CuNWs strip was used for four consecutive weeks. Based on the results obtained, we have shown that CuNWs can be a plausible candidate for the replacement of a costly catalyst for H2 generation.

CoO-Co2P composite nanosheets as highly active catalysts for sodium borohydride hydrolysis to generate hydrogen

2020 ◽  
Vol 13 (06) ◽  
pp. 2051025
Author(s):  
Hongyan Liu ◽  
Qianyu Shi ◽  
Yumei Yang ◽  
Ya-Na Yu ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Sodium Borohydride ◽  
Hydrogen Generation ◽  
Sodium Hypophosphite ◽  
X Ray Diffraction ◽  
Water Displacement ◽  
X Ray ◽  
Highly Active ◽  
Naoh Solution ◽  
Adsorption Desorption ◽  
Hydrolysis Of

In this paper, CoO[Formula: see text]Co2P composite nanocatalysts as highly active catalysts were successfully prepared for catalytic hydrolysis of sodium borohydride (NaBH[Formula: see text] to generate hydrogen. For catalyst preparation, pre-synthesized Co(OH)2 nanosheets were uniformly mixed with sodium hypophosphite (NaH2PO[Formula: see text] and then treated through vapor-phase phosphorization process. For characterization, field-emission scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), N2 adsorption–desorption measurement and X-ray photoelectric spectroscopy (XPS) were carried out, and traditional water-displacement method was performed to measure the hydrogen generation rate (HGR). It was found that component and catalytic activity of the composites were greatly affected by the ratio of Co(OH)2 to NaH2PO2. When the ratio was 2:1, the obtained catalyst composed of CoO and Co2P presented the highest HGR up to 3.94[Formula: see text]L min[Formula: see text] g[Formula: see text] using a 2[Formula: see text]wt.% NaBH[Formula: see text][Formula: see text]wt.% NaOH solution at [Formula: see text]C, and the apparent activation energy was detected as low as 27.4[Formula: see text]kJ mol[Formula: see text]. Additionally, the optimum CoO[Formula: see text]Co2P catalyst still retains 60% of the initial activity after recycling four times.

Study on the Heterojunction Photocatalyst Nb2WO8/ZnO Prepared by Ball Milling Method

2011 ◽  
Vol 399-401 ◽  
pp. 1241-1245
Author(s):  
Jin Feng Zhang ◽  
Xiao Ling Yu ◽  
Wei Liu ◽  
Shi Fu Chen
Keyword(s):  
Photocatalytic Activity ◽  
Ball Milling ◽  
Photocatalytic Oxidation ◽  
Diffuse Reflectance Spectroscopy ◽  
Fluorescence Emission ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Activity Effect ◽  
Transmission Electron ◽  
Milling Method

Orthorhombic Nb2WO8 was synthesized by solid state reaction in Nb2O5-WO3 system. Heterojunction photocatalyst Nb2WO8/ZnO was prepared by ball milling. The structural and optical properties of the photocatalyst were characterized by X-ray powder diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, and fluorescence emission spectroscopy.The photocatalytic activity was evaluated by photocatalytic oxidation of rhodamine B and reduction of Cr6+. The results showed that the photocatalytic activity of the Nb2WO8/ZnO was higher than that of ZnO. When the amount of doped Nb2WO8 was 10 wt.% and the sample was ball milled for 9 h, the Nb2WO8/ZnO showed the optimal photocatalytic activity. Effect of ball milling time on the photocatalytic activity was also investigated. The mechanisms of the increase in the photocatalytic activity were discussed by the valence band principle.

Direct Interaction of Colloidal Nanostructured ZnO and SnO2 with NO and SO2

2008 ◽  
Vol 8 (12) ◽  
pp. 6389-6397 ◽  
Author(s):  
D. Velasco-Arias ◽  
D. Díaz ◽  
P. Santiago-Jacinto ◽  
G. Rodríguez-Gattorno ◽  
A. Vázquez-Olmos ◽  
...  
Keyword(s):  
Electronic Absorption ◽  
Room Temperature ◽  
Emission Spectra ◽  
Direct Interaction ◽  
X Ray Diffraction ◽  
Wurtzite Phase ◽  
X Ray ◽  
Spontaneous Hydrolysis ◽  
Uv Visible ◽  
Hydrolysis Of

A novel and easy synthesis pathway of small SnO2 nanoparticles is reported. The method consists of the spontaneous hydrolysis of SnCl4·5H2O in dimethyl sulfoxide (DMSO), containing 3% water, at room temperature. The structure of the SnO2 nanocrystals corresponds to that of the cassiterite phase, as shown by powder X-ray diffraction and HR-TEM. The UV-visible electronic absorption and emission spectra of the SnO2 colloids are discussed. The reactions of NO(g) and SO2(g) with ZnO (wurtzite phase) and SnO2 nanocolloids are studied. The interaction of NO with ZnO nanoparticles generates the dissolution of the particles and it is quite probable that NO−13, NO−12, N2O and N2 are formed; while its contact with SO2 probably yields SO−24, SO−23 and also the dissolution of the particles is observed. When these gases are reacted with SnO2, then NO−13, NO−12, SO−23 and SO−24, were respectively obtained.

Processing of Nano Hydroxyapatite from Eggshell and Seashell

2010 ◽  
Vol 659 ◽  
pp. 159-164 ◽  
Author(s):  
Gréta Gergely ◽  
Ferenc Wéber ◽  
Mihály Tóth ◽  
Attila Lajos Tóth ◽  
Zsolt E. Horváth ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Ball Milling ◽  
Milling Process ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Attrition Milling ◽  
Milling Method ◽  
Scanning Electron

Hydroxyapatite (HAp) was successfully produced from recycled eggshell, seashell and phosphoric acid by using two different type of milling method (attrition milling and ball milling). According to the analysis, the attrition milling resulted nanosize HAp even after milling, while the ball milling process provided HAp only after a 400oC, 2 h long heat treatment. The grain size in both cases were approximately preserved during the heat treatment. The effect of temperature on stoichiometry, morphology and crystallinity of HAp powders were investigated. The structures of the HAp were characterized by X-ray diffraction and Scanning Electron Microsopy.

Structures of Li1+xMn2-XO4 Synthesized by Different Methods

2013 ◽  
Vol 652-654 ◽  
pp. 844-847 ◽  
Author(s):  
Xing Hua Liang ◽  
Tian Jiao Liu ◽  
Xiao Ming Hua
Keyword(s):  
Crystal Lattice ◽  
Ball Milling ◽  
Lithium Battery ◽  
Diffraction Peak ◽  
Coprecipitation Method ◽  
Synthetic Method ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Milling Method

In the paper, Li1+xMn2-xO4 are synthesized by ball-milling method and coprecipitation method. The phases of three compounds have been analyzed by X-ray diffraction to compare diffraction peak, crystal system and crystal lattice′ s size. Advisedly, the results show that a compound has more purity phase and better crystallinity. Synthetic method and reaction conditions of this compound are as follows: via coprecipitation method, heat the sample at 250°C for 4h in air, followed by heating at 750°C for 36h in air. This analysis provides a reasonable and valuable thinking for research of the structures of Li1+xMn2-xO4. And it is propitious to develop the positive material of lithium battery.

Synchrotron X-ray Absorption Studies of Atomic-Level Alloying in Immiscible Mixtures

1998 ◽  
Vol 524 ◽  
Author(s):  
J.-H. He ◽  
P. J. Schilling ◽  
E. Ma
Keyword(s):  
Ball Milling ◽  
Room Temperature ◽  
High Energy ◽  
Atomic Level ◽  
High Energy Ball Milling ◽  
Edge Structure ◽  
X Ray ◽  
Energy Ball ◽  
Immiscible Mixtures ◽  
X Ray Absorption

ABSTRACTAn X-ray absorption beamline has been developed recently at the electron storage ring of the LSU Center for Advanced Microstructures and Devices. Using Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES), we have studied the local atomic environments in immiscible mixtures processed by high-energy ball milling, a mechanical alloying technique involving heavy deformation. By examining the local coordination and bond distances, it is concluded that atomic-level alloying can indeed be induced between Cu and Fe through milling at room temperature, forming substitutional fcc and bcc solid solutions. In addition to single-phase regions, a two-phase region consisting of fcc/bcc solutions has been found after milling at both room temperature and liquid nitrogen temperature. In contrast to the Cu-Fe system, solid solution formation is not detectable in milled Ag-Fe and Cu-Ta mixtures. This work demonstrates the power of synchrotron EXAFS/XANES experiments in monitoring nonequilibrium alloying on the atomic level. At the same time, the results provide direct experimental evidence of the capability as well as limitations of high-energy ball milling to form alloys in positive-heat-of-mixing systems.

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