New Advances in Graphene-Based Three-Dimensional Structures

Graphene is defined as a two-dimensional network of carbon atoms with a single atom thickness and a hexagonal crystalline structure with sp2 hybridization compacted by covalent bonds. Due to its structure and geometry, graphene has unique properties, including a large specific surface area, rapid mobility of load carriers, and high thermal and electrical conductivity. However, these characteristics are limited due to the restructuring of graphene sheets. For this reason, there are many studies devoted to the synthesis of three-dimensional structures that prevent the agglomeration of the sheets and the loss of properties of the graphene structure. These three-dimensional structures have low density, high porosity and surface area, stable mechanical properties, and good mass and electron transfer properties. This chapter aims to summarize the synthesis methods of the different three-dimensional structures derived from graphene as well as their wide range of applications in environmental remediation, sensors, biomedical and energy-related applications, among many others.

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Toward the control of graphenic foams

Pure and Applied Chemistry ◽

10.1515/pac-2016-1117 ◽

2017 ◽

Vol 89 (4) ◽

pp. 565-577 ◽

Cited By ~ 3

Author(s):

Lucie Speyer ◽

Océane Louppe ◽

Sébastien Fontana ◽

Sébastien Cahen ◽

Claire Hérold

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Three Dimensional ◽

Solvothermal Reaction ◽

Synthesis Methods ◽

Structure And Properties ◽

Optimal Conditions ◽

Experimental Conditions ◽

Wide Range

AbstractGraphene-based materials are extensively studied, due to their excellent properties and their wide range of possible applications. Attention has recently been paid to three-dimensional-like graphenic structures, such as crumpled graphene sheets and graphenic foams: these kinds of materials can combine the properties of graphene associating high surface area and porosity, what is particularly interesting for energy or catalysis applications. Most of the synthesis methods leading to such structures are based on graphite oxide exfoliation and re-assembly, but in this work we focus on the preparation of graphenic foams by a solvothermal-based process. We performed a solvothermal reaction between ethanol and sodium at 220°C, during 72 h, under 200 bar, followed by a pyrolysis under nitrogen flow. An extended study of the influence of the temperature (800°C–900°C) of pyrolysis evidences an unexpected strong effect of this parameter on the characteristics of the materials. The optimal conditions provide multi-layer graphene (10 layers) foam with a surface area of 2000 m2·g−1. This work is an important step for the understanding of the mechanisms of the thermal treatment. Post-treatments in different experimental conditions are performed in order to modulate the structure and properties of the graphenic foams.

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Antibacterial performance of Berberine loaded carrageenan/konjac glucomannan hydrogels

Materials Express ◽

10.1166/mex.2021.2049 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1516-1522

Author(s):

Lei Jiang ◽

Qiuxian Chen ◽

Jia Liu ◽

Zhongjie Zhu ◽

Wei Shao

Keyword(s):

Antibacterial Effect ◽

Three Dimensional ◽

Konjac Glucomannan ◽

High Porosity ◽

Release Behavior ◽

Cell Compatibility ◽

Antibacterial Materials ◽

Antibacterial Performance ◽

Dimensional Network ◽

Good Cell

Carrageenan and konjac glucomannan are non-toxic polysaccharides which have been widely applied in the biomedical fields. Berberine as the antibacterial agent was successfully loaded into carrageenan/konjac glucomannan hydrogels. The Berberine loaded carrageenan/konjac glucomannan dried hydrogels display three-dimensional network structure, good swelling behavior and high porosity. These dried hydrogels also show controlled release behavior of Berberine. A good antibacterial effect towards S. aureus and C. albicans with good cell compatibility is exhibited. Thus, the fabricated Berberine loaded carrageenan/konjac glucomannan dried hydrogels could be considered as novel antibiotic alternative antibacterial materials.

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Covalent Organic Frameworks for Electrochemical Sensors: Recent Research and Future Prospects

Current Analytical Chemistry ◽

10.2174/1573411017666210324141739 ◽

2021 ◽

Vol 17 ◽

Author(s):

Linyu Wang ◽

Shasha Hong ◽

Yuxi Yang ◽

Yonghai Song ◽

Li Wang

Keyword(s):

Specific Surface ◽

Electrochemical Sensors ◽

Gas Adsorption ◽

Low Cost ◽

High Sensitivity ◽

Crystalline Polymer ◽

Synthesis Methods ◽

High Porosity ◽

Covalent Organic Frameworks ◽

Covalent Bonds

Background: In recent years, electrochemical sensors are widely preferred because of their high sensitivity, rapid response, low cost and easy miniaturization. Covalent organic frameworks (COFs), a porous crystalline polymer formed by organic units connected by covalent bonds, have been widely used in gas adsorption and separation, drug transportation, energy storage, photoelectric catalysis, electrochemistry and other aspects due to their large specific surface, excellent stability, high inherent porosity, good crystallinity as well as structural and functional controllability. The topological structure of COFs can be designed in advance, the structural units and linkage are diversified, and the structure is easy to be functionalized, which are all beneficial to their application in electrochemical sensors. Methods: The types, synthesis methods, properties of covalent organic frameworks and some examples of using covalent organic frameworks in electrochemical sensors are reviewed. Results: Due to their characteristics of a large specific surface, high porosity, orderly channel and periodically arranged π electron cloud, COFs are often used to immobilize metal nanoparticles, aptamers or other materials to achieve the purpose of building electrochemical sensors with high sensitivity and good stability. Since the structure of COFs can be predicted, different organic units can build COFs with different structures and properties. Therefore, organic units with certain functional groups can be selected to build COFs with certain properties and used directly for electrochemical sensors. Conclusion: COFs have a good application prospect in electrochemical sensors.

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3-D image-based numerical computations of snow permeability: links to specific surface area, density, and microstructural anisotropy

The Cryosphere ◽

10.5194/tc-6-939-2012 ◽

2012 ◽

Vol 6 (5) ◽

pp. 939-951 ◽

Cited By ~ 74

Author(s):

N. Calonne ◽

C. Geindreau ◽

F. Flin ◽

S. Morin ◽

B. Lesaffre ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Three Dimensional ◽

Analytical Models ◽

Simple Relationship ◽

Snow Density ◽

Average Value ◽

Wide Range ◽

Snow Samples

Abstract. We used three-dimensional (3-D) images of snow microstructure to carry out numerical estimations of the full tensor of the intrinsic permeability of snow (K). This study was performed on 35 snow samples, spanning a wide range of seasonal snow types. For several snow samples, a significant anisotropy of permeability was detected and is consistent with that observed for the effective thermal conductivity obtained from the same samples. The anisotropy coefficient, defined as the ratio of the vertical over the horizontal components of K, ranges from 0.74 for a sample of decomposing precipitation particles collected in the field to 1.66 for a depth hoar specimen. Because the permeability is related to a characteristic length, we introduced a dimensionless tensor K*=K/res2, where the equivalent sphere radius of ice grains (res) is computed from the specific surface area of snow (SSA) and the ice density (ρi) as follows: res=3/(SSA×ρi. We define K and K* as the average of the diagonal components of K and K*, respectively. The 35 values of K* were fitted to snow density (ρs) and provide the following regression: K = (3.0 &pm; 0.3) res2 exp((−0.0130 &pm; 0.0003)ρs). We noted that the anisotropy of permeability does not affect significantly the proposed equation. This regression curve was applied to several independent datasets from the literature and compared to other existing regression curves or analytical models. The results show that it is probably the best currently available simple relationship linking the average value of permeability, K, to snow density and specific surface area.

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Manufacture of Fine-Pored Ceramics by the Gelcasting Method

Advances in Materials Science and Engineering ◽

10.1155/2017/5923976 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Bronisław Psiuk ◽

Anna Gerle ◽

Małgorzata Osadnik ◽

Andrzej Śliwa

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Design Theory ◽

Nanoporous Materials ◽

Silica Sol ◽

High Porosity ◽

Simple Method ◽

Fine Grained ◽

Wide Range

The fine-pored materials represent a wide range of applications and searches are being continued to develop methods of their manufacturing. In the article, based on measurements on fine-grained powders of Al2O3, TiO2, and SiO2, it has been demonstrated that gelcasting can be relatively simple method of obtaining of nanoporous materials with high values of both specific surface area and open porosity. The powders were dispersed in silica sol, and the gelling initiator was NH4Cl. The usefulness of experiment design theory for developing of fine-pored materials with high porosity and specific surface area was also shown.

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Report on the Real Structure of Benzene Molecules and the Thickness of Graphene

10.21203/rs.3.rs-900329/v1 ◽

2021 ◽

Author(s):

Ning Wang ◽

Dulun Wang

Keyword(s):

Molecular Structure ◽

Layer Structure ◽

Three Dimensional ◽

Dimensional Structure ◽

Quantum Mechanical ◽

Ultraviolet Spectroscopy ◽

Quantum Mechanical Calculations ◽

Covalent Bonds ◽

Wide Range ◽

Long Time

Abstract The problem of the benzene molecular structure has not been solved for a long time. This research proposes a new concept of covalent bonds based on the existing theory: each electron shared by the nucleus corresponds to a half-valent bond, and a half-valent bond can be formed between interval carbon atoms of the benzene ring. A new theory was established. Quantum mechanical calculations results can quantitatively explain experimental results, such as the hydrogenation heat and ultraviolet spectroscopy of benzene. It has solved more than one hundred years of difficult problems. The design of the new structural forms of benzene molecules shows half-valent bonds with dotted lines, which have a wide range of adaptability, and shows the structural forms and reaction formulas of more than dozens of benzene homologs and derivatives. Under the guidance of the new theory, the stacked three-dimensional structure of benzene was explored. The thickness of the three-layer benzene tube is calculated to be almost equal to the thickness of the graphene. Therefore, it is speculated that graphene may be a three layer structure.

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Methods for tuning plasmonic and photonic optical resonances in high surface area porous electrodes

Scientific Reports ◽

10.1038/s41598-021-86813-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Lauren M. Otto ◽

E. Ashley Gaulding ◽

Christopher T. Chen ◽

Tevye R. Kuykendall ◽

Aeron T. Hammack ◽

...

Keyword(s):

Photonic Crystal ◽

Photonic Crystals ◽

Titanium Nitride ◽

Surface Area ◽

Periodic Structures ◽

High Surface ◽

High Surface Area ◽

Three Dimensional ◽

Porous Electrodes ◽

Wide Range

AbstractSurface plasmons have found a wide range of applications in plasmonic and nanophotonic devices. The combination of plasmonics with three-dimensional photonic crystals has enormous potential for the efficient localization of light in high surface area photoelectrodes. However, the metals traditionally used for plasmonics are difficult to form into three-dimensional periodic structures and have limited optical penetration depth at operational frequencies, which limits their use in nanofabricated photonic crystal devices. The recent decade has seen an expansion of the plasmonic material portfolio into conducting ceramics, driven by their potential for improved stability, and their conformal growth via atomic layer deposition has been established. In this work, we have created three-dimensional photonic crystals with an ultrathin plasmonic titanium nitride coating that preserves photonic activity. Plasmonic titanium nitride enhances optical fields within the photonic electrode while maintaining sufficient light penetration. Additionally, we show that post-growth annealing can tune the plasmonic resonance of titanium nitride to overlap with the photonic resonance, potentially enabling coupled-phenomena applications for these three-dimensional nanophotonic systems. Through characterization of the tuning knobs of bead size, deposition temperature and cycle count, and annealing conditions, we can create an electrically- and plasmonically-active photonic crystal as-desired for a particular application of choice.

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3-D image-based numerical computations of snow permeability: links to specific surface area, density, and microstructural anisotropy

The Cryosphere Discussions ◽

10.5194/tcd-6-1157-2012 ◽

2012 ◽

Vol 6 (2) ◽

pp. 1157-1180 ◽

Cited By ~ 1

Author(s):

N. Calonne ◽

C. Geindreau ◽

F. Flin ◽

S. Morin ◽

B. Lesaffre ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Three Dimensional ◽

Analytical Models ◽

Wide Range ◽

Sphere Radius ◽

Snow Microstructure ◽

Microstructural Anisotropy ◽

Good Agreement

Abstract. We used three-dimensional (3-D) images of snow microstructure to carry out numerical estimations of the full tensor of the intrinsic permeability of snow (K). This study was performed on 35 snow samples, spanning a wide range of seasonal snow types. Because the permeability is related to a characteristic length, we introduced a dimensionless tensor K*=K/ res2, where the equivalent sphere radius of ice grains (res) is computed from the specific surface area of snow (SSA) and the ice density (ρi) as follows: res=3/(SSA x ρi). Values of K*, the average of vertical and horizontal components of K*, were plotted vs. snow density (ρs) and compared to analytical models and data from the literature, showing generally a good agreement. The 35 values of K* were fitted to ρs and provide the following regression: K*=2.94 x exp(–0.013 ρs), with a correlation coefficient of 0.985. This indicates that permeability, if assumed isotropic, can be reasonably determined from SSA and ρs, which are both easily measurable in the field. However, the anisotropy coefficient of K, induced by the snow microstructure, ranges from 0.74 to 1.66 for the samples considered. This behavior is consistent with that of the effective thermal conductivity obtained in a previous work.

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Synthesis Methods For Ce(CrO4)2 · χH2O And Crystal Structures Of K2CrSO7, (NH4)2Cr2O7 And Na2Cr2O7 · 2H2O

Zeitschrift für Naturforschung B ◽

10.1515/znb-2007-0604 ◽

2007 ◽

Vol 62 (6) ◽

pp. 771-777 ◽

Cited By ~ 3

Author(s):

Barbara M. Casari ◽

Annika K. Eriksson ◽

Vratislav Langer

Keyword(s):

Three Dimensional ◽

Structural Features ◽

Solid State Reactions ◽

Synthesis Methods ◽

Exchange Reactions ◽

Hydrogen Atoms ◽

Space Group ◽

Dimensional Network ◽

High Yields ◽

Group Sharing

New and quick methods to synthesize Ce(CrO4)2 · 2H2O and Ce(CrO4)2 ·H2O, giving high yields, are described. The methods are based on exchange reactions by refluxing in water or on solid state reactions. The first crystal structure containing a chromatosulfato ion is presented. K2CrSO7 belongs to space group P21/n with a = 7.4024(1), b = 7.3908(1), c = 12.9883(2) Å , β = 90.021(1)° and Z = 4. The CrSO72− ion, consisting of one chromate group sharing one oxygen atom with one sulfate group, has a pseudo syn-C2v conformation with eclipsed oxygen atoms. K2CrSO7 forms a three dimensional network of CrSO72− ions held together by the charge balancing potassium ions, with the general structural features common with dichromate-like structures. The redetermination of the structures of (NH4)2Cr2O7 (space group C2/c, with hydrogen atoms located) and Na2Cr2O7 ·2H2O (space group P21, with hydrogen atoms located and the absolute structure established) are reported

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Effects of Surfactants on High Regularity of 3D Porous Nickel for Zn2+Adsorption Application

Journal of Nanomaterials ◽

10.1155/2014/358312 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Xiaogang Guo ◽

Xueming Li ◽

Yonghong Zheng ◽

Chuan Lai ◽

Wulin Li ◽

...

Keyword(s):

Surface Area ◽

Electrochemical Impedance ◽

Three Dimensional ◽

Absorption Spectrometry ◽

Product Formation ◽

High Porosity ◽

Porous Nickel ◽

High Regularity ◽

Additive Combination ◽

Dynamic Template

Three-dimensional porous nickel (3D-PN) film with large specific surface area (As) and high porosity has been successfully prepared by hydrogen bubble dynamic template (HBDT) method. This work presents the effects of PEG 10000 and 1,4-butynediol as new additive combination on surface morphology of the PN film. Meanwhile, the application of 3D-PN in Zn2+adsorption was preliminarily investigated in the paper. The surface area is determined as large as 166.7 cm2/mg and the porosity is 0.762 when the concentration of PEG 10000 and 1,4-butynediol was 0.3 g/100 mL and 0.1 g/100 mL, respectively. The adsorption capacity (QtandQ(%)) of PN for Zn2+is observed to be 9.145 mg/g and 0.691 for Zn(NO3)2·6H2O. The morphology and the microstructure, the product formation, theAsthe concentration of the metal ions were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), electrochemical impedance spectroscopy (EIS), and atomic absorption spectrometry (AAS), respectively.

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