Direct Measurement of Size, Three-Dimensional Shape, and Specific Surface Area of Anatase Nanocrystals

ChemPhysChem ◽  
2007 ◽  
Vol 8 (6) ◽  
pp. 805-809 ◽  
Author(s):  
Armin Feldhoff ◽  
Cecilia Mendive ◽  
Thomas Bredow ◽  
Detlef Bahnemann
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Direct Measurement ◽  
Specific Surface Area ◽  
Three Dimensional ◽  
Dimensional Shape ◽  
Three Dimensional Shape

Three-dimensional graphene encapsulated hollow CoSe2-SnSe2 nanoboxes for high performance asymmetric supercapacitors

2022 ◽  
Author(s):  
Kainan Li ◽  
Ke Zheng ◽  
Zhifang Zhang ◽  
Kuan Li ◽  
Ziyao Bian ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Specific Capacity ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Large Specific Surface Area ◽  
Composite Aerogel

Abstract Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g-1 at 0.5 A g-1, good rate capability of 212.7 F g-1 at 10 A g-1, and excellent cycle stability due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g-1 at 1A g-1 and an energy density of 11.89 W h kg-1 at 749.9 W kg-1, as well as a capacitance retention of 91.1% after 3000 cycles. This work provides a new method for preparing electrode material.

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

2012 ◽  
Vol 6 (5) ◽  
pp. 939-951 ◽  
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 ± 0.3) res2 exp((−0.0130 ± 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.

scholarly journals Three-Dimensional Versus Rectangular Sticky Yellow Traps for Western Cherry Fruit Fly (Diptera: Tephritidae)

2019 ◽  
Vol 112 (4) ◽  
pp. 1780-1788
Author(s):  
Wee L Yee
Keyword(s):  
Surface Area ◽  
Three Dimensional ◽  
Fruit Fly ◽  
Trap Surface ◽  
Trap Color ◽  
Yellow Traps ◽  
Effective Option ◽  
Dimensional Shape ◽  
Rhagoletis Indifferens ◽  
Three Dimensional Shape

Abstract The most effective traps tested against western cherry fruit fly, Rhagoletis indifferens Curran, have been the Yellow Sticky Strip (YSS) rectangle made of styrene and the three-dimensional yellow Rebell cross made of polypropylene. However, three-dimensional YSS styrene traps have never been tested against this or any other fruit fly. The main objectives of this study were to determine the efficacies of 1) YSS cross, Rebell cross, YSS cylinder, and YSS rectangle traps, 2) Rebell cross versus Rebell rectangle traps, and 3) YSS tent versus YSS rectangle traps for R. indifferens. For 1), the YSS cross caught more flies than the Rebell cross of equivalent surface area and more than a smaller YSS cylinder, but not any more than a YSS rectangle of similar surface area as the YSS cross. For 2), a Rebell cross caught more flies than a rectangle of equivalent surface area made of Rebell panels. For 3), YSS tent and YSS rectangle traps of equivalent surface area did not differ in fly captures. Results suggest that the YSS cross was more effective than the Rebell cross due to its color and that when trap color is highly attractive, three-dimensional shape may be unimportant, whereas it could be when trap color is less attractive. A new trap modeled after the YSS cross, compact but with high trap surface area to increase fly captures, could be an effective option or addition to rectangles for monitoring R. indifferens.

scholarly journals Three-Dimensional Zn0.5Cd0.5S/Reduced Graphene Oxide Hybrid Aerogel: Facile Synthesis and the Visible-Light-Driven Photocatalytic Property for Reduction of Cr(VI) in Water

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Xiao ◽  
Wenjie Zhou ◽  
Yanhua Zhang ◽  
Liangliang Tian ◽  
Hongdong Liu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Specific Surface ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Specific Surface Area ◽  
Three Dimensional ◽  
Reduced Graphene ◽  
Visible Light Driven

A series of three-dimensional ZnxCd1-xS/reduced graphene oxide (ZnxCd1-xS/RGO) hybrid aerogels was successfully synthesized based on a one-pot hydrothermal approach, which were subsequently used as visible-light-driven photocatalysts for photoreduction of Cr(VI) in water. Over 95% of Cr(VI) was photoreduced by Zn0.5Cd0.5S/RGO aerogel material within 140 min, and such photocatalytic performance was superior to that of other ZnxCd1-xS/RGO aerogel materials (x≠0.5) and bare Zn0.5Cd0.5S. It was assumed that the enhanced photocatalytic activity of Zn0.5Cd0.5S/RGO aerogel was attributed to its high specific surface area and the preferable synergetic catalytic effect between Zn0.5Cd0.5S and RGO. Besides, Zn0.5Cd0.5S/RGO aerogel materials were robust and durable enough so that they could be reused several times with merely limited loss of photocatalytic activity. The chemical composition, phase, structure, and morphology of Zn0.5Cd0.5S/RGO aerogel material were carefully examined by a number of techniques like XRD, SEM, TEM, BET, Raman characterizations, and so on. It was found that Zn0.5Cd0.5S/RGO aerogel possessed hierarchically porous architecture with the specific surface area as high as 260.8 m2 g−1. The Zn0.5Cd0.5S component incorporated in Zn0.5Cd0.5S/RGO aerogel existed in the form of solid solution nanoparticles, which were uniformly distributed in the RGO matrix.

scholarly journals Preparation and application of methimazole molecularly imprinted polymer based on silver-loaded dendritic fiber-type silica

RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13446-13457
Author(s):  
Chu Hongtao ◽  
Chen Jiaqi ◽  
Yao Dong ◽  
Yu Miao ◽  
Lin Qing ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Molecularly Imprinted Polymer ◽  
Fiber Type ◽  
Three Dimensional ◽  
High Specific Surface Area ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Radial Structure

Dendritic fiber-type silica (KCC-1) has attracted the attention of researchers because of its unique three-dimensional radial structure and high specific surface area.

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

2012 ◽  
Vol 6 (2) ◽  
pp. 1157-1180 ◽  
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.

Specific Surface Area and Three-Dimensional Nanostructure Measurements of Porous Titania Photocatalysts by Electron Tomography and Their Relation to Photocatalytic Activity

2011 ◽  
Vol 17 (2) ◽  
pp. 264-273 ◽  
Author(s):  
Kenta Yoshida ◽  
Masaki Makihara ◽  
Nobuo Tanaka ◽  
Shinobu Aoyagi ◽  
Eiji Nishibori ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Real Space ◽  
Surface Measurement ◽  
Analysis And Design ◽  
Porous Titania ◽  
Highly Porous

AbstractVarious porous titania photocatalysts are analyzed three-dimensionally in real space by electron tomography. Shapes and three-dimensional (3D) distributions of fine pores and silver (Ag) particles (2 nm in diameter) within the pores are successfully reconstructed from the 3D data. Electron tomography is applied for measuring the specific surface area of the porous structures including open and closed porosity. Calculated specific surface areas of 22.8 m2/g for a conventional sol-gel TiO2 sample and 366 m2/g for a highly porous TiO2 sample prepared using the Pluronic P-123 self-assembly process are compared with those measured by the general BET method. The real-space surface measurement indicates that the highly porous TiO2 produced by the present method using block copolymers has a greater number of effective reaction sites for the degradation of methylene blue. Electron tomography shows a great potential to contribute considerably to the nanostructural analysis and design of such catalyst materials for photocatalysis.

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