scholarly journals On-Surface Bottom-Up Construction of COF Nanoshells towards Photocatalytic H2 Production

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yao Chen ◽  
Dong Yang ◽  
Yuchen Gao ◽  
Runlai Li ◽  
Ke An ◽  
...  
Keyword(s):  
Charge Separation ◽  
Rational Design ◽  
Interfacial Polymerization ◽  
Building Blocks ◽  
H2 Production ◽  
Core Shell ◽  
Fast Diffusion ◽  
The Core ◽  
Molecule Transport ◽  
Exceptional Stability

The rational design of an outer shell is of great significance to promote the photocatalytic efficiency of core-shell structured photocatalysts. Herein, a covalent organic framework (COF) nanoshell was designed and deposited on the cadmium sulfide (CdS) core surface. A typical COF material, TPPA, featuring exceptional stability, was synthesized through interfacial polymerization using 1, 3, 5-triformylphloroglucinol (TP) and p-phenylenediamine (PA) as monomers. The nanoshell endows the CdS@TPPA nanosphere with ordered channels for unimpeded light-harvesting and fast diffusion of reactants/products and well-defined modular building blocks for spatially charge separation. Moreover, the heterojunction formed between CdS and TPPA can further facilitate the effective charge separation at the interface via lower exciton binding energy compared with that of pristine TPPA. By modulating the thickness of TPPA nanoshell, the CdS@TPPA nanosphere photocatalyst with the nanoshell thickness of about 8±1 nm exhibits the highest photocatalytic H2 evolution of 194.1 μmol h-1 (24.3 mmol g-1 h-1, 8 mg), which is superior to most of the reported COF-based photocatalysts. The framework nanoshell in this work may stimulate the thinking about how to design advanced shell architecture in the core-shell structured photocatalysts to achieve coordinated charge and molecule transport.

The ultimate step towards a tailored engineering of core@shell and core@shell@shell nanoparticles

Nanoscale ◽  
2014 ◽  
Vol 6 (22) ◽  
pp. 13483-13486 ◽  
Author(s):  
D. Llamosa ◽  
M. Ruano ◽  
L. Martínez ◽  
A. Mayoral ◽  
E. Roman ◽  
...  
Keyword(s):  
Building Blocks ◽  
Core Shell ◽  
Chemical Methods ◽  
Shell Nanoparticles ◽  
The Core ◽  
One Step ◽  
Step Generation ◽  
The One

Core@shell and core@shell@shell nanoparticles are building blocks for more sophisticated systems and a plethora of applications. The one-step generation of such complex nanoparticles is reported where the atoms of the core and shell can be easily inverted, avoiding intrinsic constraints of chemical methods.

scholarly journals Elastic forces drive nonequilibrium pattern formation in a model of nanocrystal ion exchange

2021 ◽  
Vol 118 (52) ◽  
pp. e2114551118
Author(s):  
Layne B. Frechette ◽  
Christoph Dellago ◽  
Phillip L. Geissler
Keyword(s):  
Ion Exchange ◽  
Rational Design ◽  
Chemical Potential ◽  
Chemical Species ◽  
Core Shell ◽  
Chemical Transformations ◽  
Elastic Deformations ◽  
The Core ◽  
Elastic Forces ◽  
Far From Equilibrium

Chemical transformations, such as ion exchange, are commonly employed to modify nanocrystal compositions. Yet the mechanisms of these transformations, which often operate far from equilibrium and entail mixing diverse chemical species, remain poorly understood. Here we explore an idealized model for ion exchange in which a chemical potential drives compositional defects to accumulate at a crystal’s surface. These impurities subsequently diffuse inward. We find that the nature of interactions between sites in a compositionally impure crystal strongly impacts exchange trajectories. In particular, elastic deformations which accompany lattice-mismatched species promote spatially modulated patterns in the composition. These same patterns can be produced at equilibrium in core/shell nanocrystals, whose structure mimics transient motifs observed in nonequilibrium trajectories. Moreover, the core of such nanocrystals undergoes a phase transition—from modulated to unstructured—as the thickness or stiffness of the shell is decreased. Our results help explain the varied patterns observed in heterostructured nanocrystals produced by ion exchange and suggest principles for the rational design of compositionally patterned nanomaterials.

Preparation and Characterization of Platinum/Polyaniline Core-Shell Composite

2011 ◽  
Vol 347-353 ◽  
pp. 3302-3305
Author(s):  
Jing Na Zhu ◽  
Zhen Lu Shen ◽  
Wei Min Mo ◽  
Mei Chao Li
Keyword(s):  
Electron Microscopy ◽  
Interfacial Polymerization ◽  
Core Shell ◽  
The Core ◽  
Transmission Electron ◽  
Shell Composite ◽  
Synthesis Approach ◽  
Granular Morphology ◽  
Platinum Salt

Abstract. The core-shell composite of platinum/polyaniline (Pt@PAN) had been prepared by chemical synthesis approach. Reduction of the platinum salt in aqueous solution leaded to the formation of platinum nanoparticles, and then polyaniline were synthesized by interfacial polymerization to get Pt@PAN composite. Transmission electron microscopy of Pt@PAN showed Pt particles are uniform with spherical and granular morphology. Pt@PAN was also characterized by EDAX, XPS and FTIR.

Thermal Conductivity of Core-Shell Nanostructures: From Nanowires to Nanocomposites

2005 ◽  
Author(s):  
Ronggui Yang ◽  
Gang Chen ◽  
Mildred S. Dresselhaus
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nanowires ◽  
High Efficiency ◽  
Longitudinal Direction ◽  
Building Blocks ◽  
Phonon Transport ◽  
Generic Model ◽  
Core Shell ◽  
The Core ◽  
Shell Nanostructures

Core-shell heterostructures could potentially become the building blocks of nanotechnology for electronic and optoelectronic applications. The increased surface or interface area will decrease the thermal conductivity of such nanostructures and impose challenges for the thermal management such devices. In the mean time, the decreased thermal conductivity might benefit the thermoelectric conversion efficiency. In this paper, a generic model is established to study phonon transport in core-shell nanowire structures in the longitudinal direction using the phonon Boltzmann equation. The model can be used to simulate a variety of nanostructures, including nanowires and nanocomposites by changing some of the input parameters. We first report the dependence of the thermal conductivity on the surface conditions and the core-shell geometry for silicon core - germanium shell and tubular silicon nanowires. When the scattering at the outer shell surface in the generic model is assumed to be totally specular, the core-shell nanostructure resembles a simulation unit cell of periodic two-dimensional (2-D) nanocomposites. Thermal conductivity of nanowire composites and cylindrical nanoporous material in longitudinal direction is thus predicted as a function of the size of the nanowires and nanopores, and the volumetric fraction of the constituent materials. Results of this study can be used to direct the development of high efficiency thermoelectric materials.

scholarly journals The Core-Shell Heterostructure CNT@Li2FeSiO4@C as a Highly Stable Cathode Material for Lithium-Ion Batteries

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Tao Peng ◽  
Wei Guo ◽  
Yingge Zhang ◽  
Yangbo Wang ◽  
Kejia Zhu ◽  
...  
Keyword(s):  
Cathode Material ◽  
High Performance ◽  
Rational Design ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Carbon Layer ◽  
Core Shell ◽  
Lithium Ions ◽  
The Core ◽  
Core Shell Structure

Abstract The reasonable design of nanostructure is the key to solving the inherent defects and realizing a high performance of Li2FeSiO4 cathode materials. In this work, a novel heterostructure CNT@Li2FeSiO4@C has been designed and synthesized and used as a cathode material for lithium-ion battery. It is revealed that the product has a uniform core-shell structure, and the thickness of the Li2FeSiO4 layer and the outer carbon layer is about 19 nm and 2 nm, respectively. The rational design effectively accelerates the diffusion of lithium ions, improves the electric conductivity, and relieves the volume change during the charging/discharging process. With the advantages of its specific structure, CNT@Li2FeSiO4@C has successfully overcome the inherent shortcomings of Li2FeSiO4 and shown good reversible capacity and cycle properties.

Rational design of NixCoyP@C cocatalyst for enhanced overall water splitting based on g-C3N4 photocatalyst — the synergy of carbon-shell modification and bimetal modulation

2022 ◽  
Author(s):  
Tingfeng Zhang ◽  
Xuefang Lan ◽  
Lili Wang ◽  
Jinsheng Shi ◽  
Kefeng Xiao
Keyword(s):  
Solar Energy ◽  
Water Splitting ◽  
High Performance ◽  
Rational Design ◽  
Large Scale ◽  
Low Cost ◽  
H2 Production ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

Developing high-performance and low-cost cocatalyst is crucial to realize large-scale H2 production using solar energy. Herein, a non-precious NixCoy-P@C core-shell nanoparticles (NPs) is synthesized as a high active cocatalyst for...

Accelerated charge transfer of Cd0.5Zn0.5S@ZnS core–shell nano-spheres via decoration of Ni2P and g-C3N4 toward efficient visible-light-driven H2 production

2020 ◽  
Vol 49 (19) ◽  
pp. 6259-6269 ◽  
Author(s):  
Xiaowei Ma ◽  
Qinqin Ruan ◽  
Jiakun Wu ◽  
Ying Zuo ◽  
Xipeng Pu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Visible Light ◽  
Water Splitting ◽  
Charge Separation ◽  
Light Harvesting ◽  
H2 Production ◽  
Core Shell ◽  
Visible Light Driven ◽  
Enhanced Photostability ◽  
Accelerated Charge

Unique Cd0.5Zn0.5S@ZnS-Ni2P/g-C3N4 hybrid nano-spheres demonstrate enhanced photostability, improved light-harvesting and facilitated charge separation toward efficient H2 evolution from visible-light-driven water-splitting.

Efficient visible light-driven H2 production in water by CdS/CdSe core/shell nanocrystals and an ordinary nickel–sulfur complex

Nanoscale ◽  
2014 ◽  
Vol 6 (22) ◽  
pp. 13470-13475 ◽  
Author(s):  
Ping Wang ◽  
Jie Zhang ◽  
Haili He ◽  
Xiaolong Xu ◽  
Yongdong Jin
Keyword(s):  
Visible Light ◽  
Multicomponent System ◽  
H2 Production ◽  
Core Shell ◽  
Cdse Core ◽  
The Core ◽  
System P ◽  
Visible Light Driven

A simple nickel–sulfur complex is developed for the efficient visible light-driven H2 production in the core/shell QD-based multicomponent system.

Influence of heat treatment on hole transfer dynamics in core-shell quantum dot/organic hole conductor hybrid films

2017 ◽  
Vol 31 (23) ◽  
pp. 1750218 ◽  
Author(s):  
Mingye Sun ◽  
Youjin Zheng ◽  
Lei Zhang ◽  
Liping Zhao ◽  
Bing Zhang
Keyword(s):  
Heat Treatment ◽  
Rational Design ◽  
Effective Means ◽  
Treatment Temperature ◽  
Core Shell ◽  
Hybrid Films ◽  
Cdse Qds ◽  
Obvious Effect ◽  
Hole Transfer ◽  
The Core

The influence of heat treatment on hole transfer (HT) processes from the CdSe/ZnS and CdSe/CdS/ZnS quantum dots (QDs) to 4,4[Formula: see text],4[Formula: see text]-Tris(carbazol-9-yl)-triphenylamine (TCTA) in QD/TCTA hybrid films has been researched with time-resolved photoluminescence (PL) spectroscopy. The PL dynamic results demonstrated a heat-treatment-temperature-dependent HT process from the core-shell CdSe QDs to TCTA. The HT rates and efficiencies can be effectively increased due to reduced distance between core-shell CdSe QDs and TCTA after heat treatment. The CdS shell exhibited a more obvious effect on HT from the core-shell CdSe QDs to TCTA than on electron transfer to TiO2, due to higher barrier for holes to tunnel through CdS shell and larger effective mass of holes in CdS than electrons. These results indicate that heat treatment would be an effective means to further optimize solid-state QD sensitized solar cells and rational design of CdS shell is significant.

Magnetic Properties of Fe3O4/CoFe2O4 Composite Nanoparticles with Core/Shell Architecture

2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
Cofe2o4 Nanoparticles ◽  
Core Diameter ◽  
The Core ◽  
Shell Particles ◽  
Interface Parameters ◽  
Shell Composite

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.

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