scholarly journals Fabrication of β-Ni(OH)2 Particles by Alkaline Etching Layered Double Hydroxides Precursor for Supercapacitor

2022 ◽  
Vol 9 ◽  
Author(s):  
Lumei Chen ◽  
Xiaotong Yang ◽  
Ye Tian ◽  
Yiping Wang ◽  
Xuhui Zhao ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Layered Double Hydroxides ◽  
Active Material ◽  
Great Influence ◽  
Rate Capability ◽  
Precipitation Reaction ◽  
Double Hydroxides

We report the facile preparation of β-Ni(OH)2 particles by etching a NiAl-layered double hydroxides (NiAl-LDHs) precursor with KOH solution. The amphoteric Al3+ ions in LDHs crystal were selectively dissolved out by KOH solution and LDHs crystals were proposed to be in situ topologically transformed to form β-Ni(OH)2. Alkaline concentration has a great influence on the structure, morphology, specific surface area, and porous structure of the resulting samples. Compared to LDHs precursor and β-Ni(OH)2 prepared by a precipitation reaction, the sample etched in 10 M KOH solution has enhanced specific capacitance (829 F/g at 1 A/g), high rate capability (capacitance retention 57.3% with current density 8 A/g), and good charge/discharge stability. We suggested that the high accessible specific surface area and appropriate porous structure, which is conducive to full contact between active material and electrolyte, can improve the utilization rate of the active material to increase the rate capacity of the 10 M KOH-etched sample.

Tuneable ultra high specific surface area Mg/Al-CO3layered double hydroxides

2015 ◽  
Vol 44 (37) ◽  
pp. 16392-16398 ◽  
Author(s):  
Chunping Chen ◽  
Aunchana Wangriya ◽  
Jean-Charles Buffet ◽  
Dermot O'Hare
Keyword(s):  
Organic Solvent ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Layered Double Hydroxides ◽  
High Specific Surface Area ◽  
Double Hydroxides

We report the synthesis of tuneable ultra high specific surface area Aqueous Miscible Organic solvent-Layered Double Hydroxides (AMO-LDHs).

scholarly journals Properties of calcium sulfoaluminate cement-based grouting materials with LiAl-layered double hydroxides slurries

2020 ◽  
Vol 29 ◽  
pp. 2633366X2092652 ◽  
Author(s):  
Haiyan Li ◽  
Xianping Wang ◽  
Xuemao Guan ◽  
Dinghua Zou
Keyword(s):  
Compressive Strength ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Layered Double Hydroxides ◽  
Setting Time ◽  
Hydration Products ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Double Hydroxides

In this study, LiAl-layered double hydroxides Lithium aluminum hydrotalcite (LiAl-LDH) with different specific surface area were prepared by the separate nucleation and aging steps (SNAS) method and then were employed to prepare calcium sulfoaluminate cement-based grouting material (CBGM) paste. The influence of LiAl-LDH slurries on fresh and hardened properties of the CBGM paste was investigated in terms of fluidity, stability, setting time, and compressive strength. Additionally, the hydration process and hydration products of the CBGM paste were characterized by hydration heat, X-ray diffraction, differential thermal analysis–thermogravimetry, and Fourier transform infrared analyses. The acquired results illustrated that LiAl-LDH with larger specific surface area led to a faster hydration rate at early age, a lower fluidity, a shorter setting time, and a higher stability. Furthermore, due to the crystal nucleation effect, the addition of LiAl-LDH slurries did not cause a new phase to form but changed the morphology and increased the amount of hydration products, yielding higher compressive strength.

scholarly journals Synthesis of dense porous layered double hydroxides from struvite

2021 ◽  
Vol 23 (4) ◽  
pp. 1616-1620
Author(s):  
W. L. Joyce Kwok ◽  
Hongri Suo ◽  
Chunping Chen ◽  
D. W. Justin Leung ◽  
Jean-Charles Buffet ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Layered Double Hydroxides ◽  
Pore Volume ◽  
Wastewater Treatment Plants ◽  
High Specific Surface Area ◽  
Large Pore Volume ◽  
Double Hydroxides

An atom economic synthesis of dense porous layered double hydroxides (SLDHs) using an undesirable waste in wastewater treatment plants (struvite) is reported. The obtained SLDHs show high specific surface area, large pore volume and high density.

scholarly journals High MB Solution Degradation Efficiency of FeSiBZr Amorphous Ribbon with Surface Tunnels

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3694 ◽  
Author(s):  
Qi Chen ◽  
Zhicheng Yan ◽  
Hao Zhang ◽  
Lai-Chang Zhang ◽  
Haijian Ma ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Free Volume ◽  
Specific Surface Area ◽  
Degradation Rate ◽  
High Efficiency ◽  
Amorphous Ribbon ◽  
Degradation Efficiency ◽  
Characteristic Distance

The as spun amorphous (Fe78Si9B13)99.5Zr0.5 (Zr0.5) and (Fe78Si9B13)99Zr1 (Zr1) ribbons having a Fenton-like reaction are proved to bear a good degradation performance in organic dye wastewater treatment for the first time by evaluating their degradation efficiency in methylene blue (MB) solution. Compared to the widely studied (Fe78Si9B13)100Zr0 (Zr0) amorphous ribbon for degradation, with increasing cZr (Zr atomic content), the as-spun Zr0, Zr0.5 and Zr1 amorphous ribbons have gradually increased degradation rate of MB solution. According to δc (characteristic distance) of as-spun Zr0, Zr0.5 and Zr1 ribbons, the free volume in Zr1 ribbon is higher Zr0 and Zr0.5 ribbons. In the reaction process, the Zr1 ribbon surface formed the 3D nano-porous structure with specific surface area higher than the cotton floc structure formed by Zr0 ribbon and coarse porous structure formed by Zr0.5 ribbon. The Zr1 ribbon’s high free volume and high specific surface area make its degradation rate of MB solution higher than that of Zr0 and Zr0.5 ribbons. This work not only provides a new method to remedying the organic dyes wastewater with high efficiency and low-cost, but also improves an application prospect of Fe-based glassy alloys.

Fabrication of an N-doped mesoporous bio-carbon electrocatalyst efficient in Zn–air batteries by an in situ gas-foaming strategy

2019 ◽  
Vol 55 (100) ◽  
pp. 15117-15120 ◽  
Author(s):  
Hong Wang ◽  
Wei Li ◽  
Zhiwei Zhu ◽  
Yijuan Wang ◽  
Pan Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrocatalytic Activity ◽  
High Specific Surface Area ◽  
Carbon Catalyst ◽  
Gas Foaming

An N-doped bio-carbon catalyst with a hierarchical interconnected macro/meso-porous structure and high specific surface area exhibited significantly enhanced electrocatalytic activity.

Effect of aging and alkali activator on the porous structure of a geopolymer

2014 ◽  
Vol 47 (1) ◽  
pp. 316-324 ◽  
Author(s):  
Prune Steins ◽  
Arnaud Poulesquen ◽  
Fabien Frizon ◽  
Olivier Diat ◽  
Jacques Jestin ◽  
...  
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Inorganic Polymers ◽  
Porous Network ◽  
X Ray ◽  
Alkali Activator ◽  
Effects Of Aging

Nitrogen sorption and small- and wide-angle X-ray and neutron scattering techniques were used to study the porous structure of geopolymers, inorganic polymers synthesized by reaction of a strongly alkaline solution and an aluminosilicate source (metakaolin). The effects of aging and the use of alkali activators (Na+, K+) of different sizes were investigated at room temperature. The influence of aging time on the microstructure of both geopolymer matrixes was verified in terms of pore volume and specific surface area. The results suggested a refinement of the porosity and therefore a reduction in the pore volume over time. Regardless of the age considered, some characteristics of the porous network such as pore size, shape and distribution depend on the alkali activator used. Whatever the technique considered, the potassium geopolymer has a greater specific surface area than the sodium geopolymer. According to the scattering results, the refinement of the porosity can be associated with, first, a densification of the solid network and, secondly, a partial closure of the porosity at the nanometre scale. The kinetics are much slower for the sodium geopolymer than for the potassium geopolymer in the six months of observation.

Micro/Nanostructured α-Fe2O3 with Structural Enhanced Removal Capacity of Cr(VI) Ions

2012 ◽  
Vol 518-523 ◽  
pp. 1753-1756 ◽  
Author(s):  
Gang Liu ◽  
Quan Deng ◽  
Yong Yang ◽  
Hui Min Wang ◽  
Guo Zhong Wang
Keyword(s):  
Specific Surface ◽  
Porous Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Diameter ◽  
High Specific Surface Area ◽  
Removal Capacity

We have succeeded in preparing micro/nanostructured α-Fe2O3 spheres (MNFSs). The resulted MNFSs have an average diameter of about 5 µm, and are constructed by subunits of interlinked and elongated particles with a diameter of 20~60 nm. MNFSs show an obviously structural enhanced Cr(VI) removal capacity (5.88 mg/g) compared with nanoscaled (0.81 mg/g) and microscaled α-Fe2O3 (0.1 mg/g) due to its high specific surface area together with the special porous structure. Moreover, MNFSs show good availability of reusing to remove Cr(VI) ions.

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