Biopolymer-assisted synthesis of assembled g-C3N4 open frameworks with electron delocalization channels for prompted H2 production

2022 ◽  
Author(s):  
Yao Liu ◽  
Guangzhao Wang ◽  
Yunfei Li ◽  
Peng Du ◽  
Xuefang Lan ◽  
...  
Keyword(s):  
Water Splitting ◽  
Three Dimensional ◽  
H2 Production ◽  
Electron Delocalization ◽  
Two Dimensional

Three-dimensional (3D) photocatalysts can overcome the serious two-dimensional (2D) nanosheet aggregation reduced by unavoidable Van del Waals forces. However, its water splitting efficiency needs further improvement via boosting the exciton...

Anchoring Zn0.5Cd0.5S solid solution onto 2D porous Co-CoO nanosheets for highly improved photocatalytic H2 generation

2021 ◽  
Author(s):  
Xueyou Gao ◽  
Deqian Zeng ◽  
Qingru Zeng ◽  
Zongzhuo Xie ◽  
Toyohisha Fujita ◽  
...  
Keyword(s):  
Solid Solution ◽  
Water Splitting ◽  
Noble Metal ◽  
H2 Production ◽  
Two Dimensional ◽  
Photocatalytic Water Splitting ◽  
H2 Generation ◽  
Photocatalytic H2 Generation

Co-based cocatalysts have attracted considerable attention as potential alternatives for the noble-metal (Pt) in photocatalytic water splitting. However, the two-dimensional (2D) porous-structured Co-based cocatalysts toward photocatalytic hydrogen (H2) production application...

Two-dimensional layered Type-II MS2/BiOCl (M = Zr, Hf) van der Waals heterostructures: A promising photocatalysts for hydrogen generation

2021 ◽  
Author(s):  
Francis Opoku ◽  
Osei Akoto ◽  
Samuel Osei-Bonsu Oppong ◽  
Anthony Apeke Adimado
Keyword(s):  
Energy Storage ◽  
Water Splitting ◽  
Hydrogen Generation ◽  
Van Der Waals ◽  
H2 Production ◽  
Type Ii ◽  
Two Dimensional ◽  
Van Der Waals Heterostructures ◽  
Photocatalytic Water Splitting ◽  
Van Der Waals Heterostructure

Sustainable hydrogen (H2) production via photocatalytic water splitting is considered the most promising energy storage, where two-dimensional van der Waals heterostructure, composed of two or more 2D monolayer materials, has...

Well-aligned metal–organic framework array-derived CoS2 nanosheets toward robust electrochemical water splitting

2018 ◽  
Vol 2 (9) ◽  
pp. 1732-1738 ◽  
Author(s):  
Na Yao ◽  
Tan Tan ◽  
Fulin Yang ◽  
Gongzhen Cheng ◽  
Wei Luo
Keyword(s):  
Water Splitting ◽  
Hydrogen Evolution Reaction ◽  
Metal Organic Framework ◽  
Three Dimensional ◽  
Alkaline Media ◽  
Carbon Cloth ◽  
Two Dimensional ◽  
Metal Organic ◽  
Hierarchical Architectures ◽  
Electrochemical Water Splitting

Highly open three-dimensional (3D) hierarchical architectures composed of two-dimensional (2D) CoS2 nanosheets grown on carbon cloth (CoS2 NS/CC) have been synthesized by vulcanizing well-aligned MOF-array precursors and further used as superior bifunctional electrocatalysts toward the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and overall water splitting under alkaline media.

scholarly journals Hierarchically Ordinated Two-Dimensional MoS2 Nanosheets on Three-Dimensional Reduced Graphene Oxide Aerogels as Highly Active and Stable Catalysts for Hydrogen Evolution Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 182
Author(s):  
Hyeonggeun Choi ◽  
Suok Lee ◽  
Min-Cheol Kim ◽  
Yeonsu Park ◽  
A-Rang Jang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrogen Production ◽  
Water Splitting ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Mos2 Nanosheets ◽  
Reduced Graphene ◽  
Electrochemical Water Splitting

Hydrogen gas (H2) is being intensively proposed as a next-generation clean energy owing to the depletion of fossil fuels. Electrochemical water splitting is one of the most promising processes for hydrogen production. Furthermore, many efforts focusing on electrochemical water splitting have been made to develop low-cost, electrochemically active, and stable catalysts for efficient hydrogen production. MoS2 has emerged as an attractive material for developing catalysts for the hydrogen evolution reaction (HER). Hence, in this study, we design hierarchically ordinated two-dimensional (2D) MoS2 nanosheets on three-dimensional (3D) reduced graphene oxide (rGO) (H-2D/3D-MoS2-rGO) aerogel structures as a new class of electrocatalysts for the HER. We use the one-pot hydrothermal synthesis route for developing high-performance electroactive materials for the HER. The as-prepared H-2D/3D-MoS2-rGO contains a unique 3D hierarchical structure providing large surface areas owing to the 3D porous networks of rGO and more active sites owing to the many edge sites in the MoS2 nanosheets. In addition, the H-2D/3D-MoS2-rGO structure exhibits remarkable electrochemical properties during the HER. It shows a lower overpotential than pure MoS2 and excellent electrochemical stability owing to the large number of active sites (highly exposed edge sites) and high electrical conductivity from the rGO structure.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

A linearity test for thick specimens imaged by HVEM over a 180° angular range

1991 ◽  
Vol 49 ◽  
pp. 552-553
Author(s):  
Yu Liu
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Angular Range ◽  
Two Dimensional ◽  
Back Projection ◽  
Line Integral ◽  
Exponential Law ◽  
Transmission Electron ◽  
Absorption Law ◽  
Linearity Test

The image obtained in a transmission electron microscope is the two-dimensional projection of a three-dimensional (3D) object. The 3D reconstruction of the object can be calculated from a series of projections by back-projection, but this algorithm assumes that the image is linearly related to a line integral of the object function. However, there are two kinds of contrast in electron microscopy, scattering and phase contrast, of which only the latter is linear with the optical density (OD) in the micrograph. Therefore the OD can be used as a measure of the projection only for thin specimens where phase contrast dominates the image. For thick specimens, where scattering contrast predominates, an exponential absorption law holds, and a logarithm of OD must be used. However, for large thicknesses, the simple exponential law might break down due to multiple and inelastic scattering.

An Image Reconstruction System Applied to High Voltage Microscopy

1975 ◽  
Vol 33 ◽  
pp. 292-293
Author(s):  
D. E. Johnson
Keyword(s):  
High Voltage ◽  
Prior Information ◽  
Block Diagram ◽  
Three Dimensional ◽  
Real Space ◽  
Two Dimensional ◽  
Efficient Manner ◽  
Fourier Methods ◽  
Tilt Series ◽  
Methods Of Reconstruction

Increased specimen penetration; the principle advantage of high voltage microscopy, is accompanied by an increased need to utilize information on three dimensional specimen structure available in the form of two dimensional projections (i.e. micrographs). We are engaged in a program to develop methods which allow the maximum use of information contained in a through tilt series of micrographs to determine three dimensional speciman structure.In general, we are dealing with structures lacking in symmetry and with projections available from only a limited span of angles (±60°). For these reasons, we must make maximum use of any prior information available about the specimen. To do this in the most efficient manner, we have concentrated on iterative, real space methods rather than Fourier methods of reconstruction. The particular iterative algorithm we have developed is given in detail in ref. 3. A block diagram of the complete reconstruction system is shown in fig. 1.

Computer Assisted Image Reconstruction of Oligomer Structure

1976 ◽  
Vol 34 ◽  
pp. 472-473
Author(s):  
A.M. Jones ◽  
A. Max Fiskin
Keyword(s):  
Three Dimensional ◽  
Depth Of Field ◽  
Computer Assisted ◽  
Projection Data ◽  
Two Dimensional ◽  
Single Particles ◽  
Dimensional Reconstruction ◽  
Computer Assisted Image ◽  
The Fourier Transform ◽  
Space Approach

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.

Polymorphic phase transition of a membrane protein - analysis of continuous diffuse electron diffraction intensity

1986 ◽  
Vol 44 ◽  
pp. 166-167
Author(s):  
Douglas L. Dorset ◽  
Andrew K. Massalski
Keyword(s):  
Molecular Sieve ◽  
Three Dimensional ◽  
Pore Geometry ◽  
Two Dimensional ◽  
Diffraction Intensity ◽  
Polymorphic Phase Transition ◽  
E Coli ◽  
Crystallographic Study ◽  
Hexagonal Form ◽  
Polymorphic Forms

Matrix porin, the ompF gene product of E. coli, has been the object of a electron crystallographic study of its pore geometry in an attempt to understand its function as a membrane molecular sieve. Three polymorphic forms have been found for two-dimensional crystals reconstituted in phospholipid, two hexagonal forms with different lipid content and an orthorhombic form coexisting with and similar to the hexagonal form found after lipid loss. In projection these have been shown to retain the same three-fold pore triplet geometry and analyses of three-dimensional data reveal that the small hexagonal and orthorhombic polymorphs have similar structure as well as unit cell spacings.

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