Embedded High Density Metal Nanoparticles with Extraordinary Thermal Stability Derived from Guest−Host Mediated Layered Double Hydroxides

Zhao, Meng‐Qiang; Zhang, Qiang; Zhang, Wei; Huang, Jia‐Qi; Zhang, Yinghao; Su, Dang Sheng; Wei, Fei

doi:10.1021/ja106421g

Cited by 180 publications

(106 citation statements)

References 40 publications

Supporting

Mentioning

105

Contrasting

Unclassified

Order By: Relevance

“…4a). In the reduction process, as excess NaBH 4 was used, the BH 4 À concentration can be considered as a constant throughout the reaction. The ratio of C t and C 0 , where C t and C 0 are 4-NP concentrations at time t and 0, respectively, was measured from the relative intensity of the respective absorbances, A t /A 0 .…”

Section: -7mentioning

confidence: 99%

“…In summary, we have successfully developed a novel, efficient and scalable strategy for the development of advanced hollow hierarchical Ni@C catalysts with highly dispersed Ni NPs embedded in the well-graphitized carbon matrix by using organic-inorganic layered nickel hydroxides as single-source precursors. The integration of highly dispersed embedded Ni NPs, high Ni NPs content (up to $88.01 wt%), well-graphitized carbon matrix as well as strong interaction between the Ni NPs and carbon in the Ni@C catalysts make them excellent active, stable catalysts toward the reduction of 4-NP by NaBH 4 . The catalysts can be successfully recycled by an external magnet aer the catalytic reduction and reused for at least ten successive cycles of reaction with stable conversion efficiency of around 87%, which make the products be attractive materials for various potential applications.…”

Section: -7mentioning

confidence: 99%

See 1 more Smart Citation

Facile synthesis of hollow hierarchical Ni@C nanocomposites with well-dispersed high-loading Ni nanoparticles embedded in carbon for reduction of 4-nitrophenol

et al. 2018

View full text Add to dashboard Cite

Hollow hierarchical Ni@C nanocomposites with highly dispersed Ni nanoparticles (NPs) embedded in wellgraphitized carbon matrix have been synthesized by solid-state pyrolysis of simple, well-defined organicinorganic layered nickel hydroxide. The integration of highly dispersed Ni NPs, high Ni NPs content (up to $88.01 wt%), well-graphitized carbon as well as strong Ni/carbon interaction in the Ni@C make them display excellent catalytic activity and stable magnetic recyclability toward the reduction of 4-nitrophenol by NaBH 4 .The development of more efficient and stable catalysts has been an increasingly important goal for chemists and materials scientists for both economic and environmental reasons. As efficient and cost-effective non-noble metal, Ni NPs have attracted much attention owing to their potential applications in electronic or optical materials, as well as in catalysis.1-3 In general, the overall performance of Ni NPs depends heavily upon the size, shape and dispersion. It is widely accepted that a higher catalytic activity can be achieved by increasing the surface area of the specic active phase of the catalysts through reducing the size of the corresponding catalytic particles. 4-7However, due to their high surface area to volume ratio, Ni NPs are typically unstable and tend to sinter into larger species, especially at high metal contents, which results in a dramatic decrease in catalytic activity and selectivity. It is thus highly important to prepare stable Ni NPs with uniform dispersion and narrow size distribution to promote their catalytic activities.Over the past decades, embedding of Ni NPs inside the porous supports has been proved to enhance catalytic activity and impede nanoparticle sintering. [8][9][10][11][12][13][14][15] The advantages of carbon supports with respect to conventional oxidic supports, like silica and zirconia, involve the high specic surface area, high stability, intrinsic high electrical conductivity, as well as easy recovery of metal active phases from spent catalysts by burning away carbon. To date, various methods for preparing carbon-supported Ni NPs have been developed. [16][17][18][19][20][21][22] In particular, incipient wetness impregnation and coprecipitation are commonly used methods to prepare these supported catalysts. It is well known that traditional carbons (including activated carbon, carbon nanotubes, graphene and carbon nanobers) are poor in functional groups and a complex functionalization pre-treatment (such as acid oxidation, ionic liquid linking or polymer wrapping) is always required. In addition, the excess reducing regents are also needed for the reduction of Ni NPs. Although a high dispersion of Ni NPs on porous carbon can be achieved by employing this methods, this tedious post-synthetic method renders instable catalysts with dispersed Ni NPs on the external surface or near pore mouths and Ni NPs still have a tendency to be sintered, especially at high metal loading or high temperature, resulting in a signicant loss of reactivity because of...

show abstract

Section: -7mentioning

confidence: 99%

Section: -7mentioning

confidence: 99%

Facile synthesis of hollow hierarchical Ni@C nanocomposites with well-dispersed high-loading Ni nanoparticles embedded in carbon for reduction of 4-nitrophenol

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Hydrotalcite-like layered clays, also well-known LDH, [15][16][17][18] have been extensively explored in the field of catalysts and catalyst supports, 19 flame retardants, 20 anion exchange, 21 optical and electrical functional materials, 22 and Nano-additives. LDH are rich in lamellae as electrode materials for supercapacitors.…”

mentioning

confidence: 99%

Investigation of the Electrochemical Properties of CoAl-Layered Double Hydroxide/Ni(OH)₂

Musharavati

Sun

et al. 2018

J. Electrochem. Soc.

View full text Add to dashboard Cite

Layered double hydroxides (LDH) as active electrode materials have become the focus of research in energy storage applications. The manufacturing of excellent electrochemical performance of the LDH electrode is still a challenge. In this paper, the production of CoAl-LDH@Ni(OH) 2 is carried out in two steps, including hydrothermal and electrodeposition techniques. The prominent features of this electrode material are shown in the structural and morphological aspects, and the electrochemical properties are investigated by improving the conductivity and cycle stability. The core of this experimental study is to investigate the properties of the materials by depositing different amounts of nickel hydroxide and changing the loading of the active materials. The experimental results show that the specific capacity is 1810.5F · g −1 at 2 A/g current density and the cycle stability remained at 76% at 30 A g −1 for 3000 cycles. Moreover, a solid-state asymmetric supercapacitor with CoAl-LDH@Ni(OH) 2 as the positive electrode and multi-walled carbon nanotube coated on the nickel foam as the negative electrode delivers high energy density (16.72 Wh kg −1 at the power density of 350.01 W kg −1 ). This study indicates the advantages of the design and synthesis of layered double hydroxides, a composite with excellent electrochemical properties that has potential applications in energy storage. Supercapacitors (SCs) are currently of widespread interest in energy storage, which has become a research area due to the development of various energy storage devices, long cycle life, high power density, high safety, and low maintenance costs. Numerous studies have concentrated on the enhancing the performance of the electrode material. Electrochemical capacitors (ECs), also known as supercapacitors, 1,2 are a new type of energy storage device that have been developed in recent years. Typically, according to the charge storage mechanism of different electrode materials, 3-5 the use of supercapacitors can be divided into two categories including the electric double layer capacitor (EDLC), Faraday pseudocapacitor and hybrid supercapacitor.6-9 The electric double layer capacitor uses high surface area carbon as the electrode material, while the Faraday pseudocapacitor uses a transition metal oxide or a conductive polymer as an electrode material.The electric double layer capacitor is a new capacitor which is based on the interface of the double layer theory.10,11 The reversible electrostatic adsorption /desorption on the electrode surface is used to store the charge.12 By arrangement of the opposite sign charge an electric double layer is formed in the vicinity of the electrode/electrolyte interface, a so-called "electric double layer capacitor".13,14 Its working principle is: the electrode surface and solution on both sides of the electrolyte solution appear on the opposite sides of the excess charge.Hydrotalcite-like layered clays, also well-known LDH, 15-18 have been extensively explored in the field of catalysts and catalyst supports...

show abstract

“…By contrast, for particles larger than 5 nm, the formation of MWCNTs encapsulated particles and led to catalyst deactivation (Figure 2(b)-(e)). We also explored the idea of chemically-mediated-precursorinduced formation of metal nanoparticles with higher density (ranging from 10 15 to 10 16 m 2 ) on MoO 4 2 intercalated LDH flakes [18,19]. The metal nanoparticles were much smaller and had better thermal stability because of the pinning effect, and the Mo-containing LDH flakes were demonstrated to be excellent catalyst precursors for the production of aligned SWCNTs.…”

Section: Wall Number and Diameter-mediated Cnt Productionmentioning

confidence: 99%

A review of the large-scale production of carbon nanotubes: The practice of nanoscale process engineering

et al. 2011

Self Cite

View full text Add to dashboard Cite

Carbon nanotubes (CNTs) are nanomaterials that have attracted great research interest because of their unique properties and promising applications. The controllable synthesis of CNTs is a precondition for their broad application. In this review, we consider nanoscale process engineering and assess recent progress in the mass production of ultra-long, inexpensive CNTs with good alignment as well as tunability in wall number and diameter for fundamental and engineering science applications across multiple scales. Cutting-edge nanoscale process engineering research in the areas of physics, chemistry, materials, engineering, ecology, and social science will allow us to obtain high added value and multi-functional advanced CNTs. The synthesis of CNTs with controllable chirality, good-alignment, and predetermined sizes and lengths still presents great challenges. Through multidisciplinary scientific research, advanced CNT-based materials will promote the development of a sustainable society. According to the wall number of a CNT, it can be classified as a SWCNT, double-walled CNT (DWCNT), triple-walled CNT (TWCNT), or multi-walled CNT (MWCNT). Because of the covalent sp 2 bonds between individual carbon atoms, a nanotube can have a Young's modulus between 1.2-5.5 TPa, a tensile strength about a hundred times greater than that of steel, and can tolerate large strains before mechanical failure. A CNT can be a metal, semiconductor, or small-gap semiconductor. The state of the CNT depends heavily on the (m, n) indices, and, therefore, on the diameter and chirality. CNTs also possess tunable surfaces characteristics, well-defined hollow interiors, and high biocompatibility with living systems. Based on these properties, many potential applications, including both large-volume applications (such as conductive, electromagnetic, microwave absorbing, high-strength composites; super capacitor, or battery electrodes; catalyst and catalyst support; field emission displays; and transparent conducting films) and limited-volume applications (such as scanning probe tips; drug delivery systems; electronic devices; sensors; and actuators) have been proposed [2]. Controllable mass production of CNTs with the desired structures and properties is essential for future applications. In the past 20 years, arc discharge, laser ablation, and chemical vapor deposition (CVD) methods have been developed to produce CNTs in sizeable quantities. In CVD methods, the catalytic decomposition of a carbon feedstock into carbon and hydrogen atoms is initiated on an active catalyst surface, where the tubular CNTs grown. CVD growth can be achieved under mild conditions (such as normal pressure

show abstract

Embedded High Density Metal Nanoparticles with Extraordinary Thermal Stability Derived from Guest−Host Mediated Layered Double Hydroxides

Cited by 180 publications

References 40 publications

Facile synthesis of hollow hierarchical Ni@C nanocomposites with well-dispersed high-loading Ni nanoparticles embedded in carbon for reduction of 4-nitrophenol

Facile synthesis of hollow hierarchical Ni@C nanocomposites with well-dispersed high-loading Ni nanoparticles embedded in carbon for reduction of 4-nitrophenol

Investigation of the Electrochemical Properties of CoAl-Layered Double Hydroxide/Ni(OH)₂

A review of the large-scale production of carbon nanotubes: The practice of nanoscale process engineering

Contact Info

Product

Resources

About

Embedded High Density Metal Nanoparticles with Extraordinary Thermal Stability Derived from Guest−Host Mediated Layered Double Hydroxides

Cited by 180 publications

References 40 publications

Facile synthesis of hollow hierarchical Ni@C nanocomposites with well-dispersed high-loading Ni nanoparticles embedded in carbon for reduction of 4-nitrophenol

Facile synthesis of hollow hierarchical Ni@C nanocomposites with well-dispersed high-loading Ni nanoparticles embedded in carbon for reduction of 4-nitrophenol

Investigation of the Electrochemical Properties of CoAl-Layered Double Hydroxide/Ni(OH)2

A review of the large-scale production of carbon nanotubes: The practice of nanoscale process engineering

Contact Info

Product

Resources

About

Investigation of the Electrochemical Properties of CoAl-Layered Double Hydroxide/Ni(OH)₂