Special Issue "Nanoporous Metals"

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (31 May 2018)

Special Issue Editor

Guest Editor
Prof. Dr. Takeshi Fujita

School of Environmental Science and Engineering, Kochi University of Technology, 185 Miyanokuchi, Tosayamada, Kami City, Kochi 782-8502, Japan
Website | E-Mail
Interests: nanoporous metal; catalysis; 2D materials; transmission electron microscopy

Special Issue Information

Dear Colleagues,

Nanoporous metals prepared by the dealloying (selective leaching) of a solid-solution alloy or compound represent an emerging class of materials. Nanoporous metal has a three-dimensional structure of randomly interpenetrating ligaments/nanopores, of which sizes can be tuned, from 5 nm to several tens of microns, by altering conditions (dealloying time, temperature and subsequent thermal coarsening). Nanoporous metals have several merits for application compared with other nanostructured materials; bicontinuous structure, tunable pore size, bulk form, good conductivity, and high structural stability. Therefore, nanoporous metal is an ideal 3D material to meet various applications, and the attractive versatile functionality such as catalysis, optical sensing, actuation or energy storage and conversion has been emerged. The understanding of the atomistic description of surface roughening and nanopore formation is also important to maximize the functionality.

This Special Issue focuses on recent advances of nanoporous metals by alloy corrosion from fundamental aspects to various applications. We welcome contributions from experimentalists, theorists, and computational scientists in this research field.

Prof. Takeshi Fujita
Guest Editor

Manuscript Submission Information

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Keywords

  • Nanoporous metal
  • Dealloy
  • Catalysis
  • Energy storage and conversion
  • Pore formation
  • Optical sensing
  • Actuation
  • Mechanical property

Published Papers (6 papers)

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Research

Open AccessArticle Fabrication of a Porous Metal via Selective Phase Dissolution in Al-Cu Alloys
Metals 2018, 8(6), 378; https://doi.org/10.3390/met8060378
Received: 16 April 2018 / Revised: 17 May 2018 / Accepted: 21 May 2018 / Published: 24 May 2018
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Abstract
Through free corrosion, a new low cost porous material was successfully fabricated by removing a single phase of a binary aluminum-copper alloy. This selective phase dissolution was carried out an Al-Al2Cu eutectic alloy of the Al-Cu binary system and additionally for
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Through free corrosion, a new low cost porous material was successfully fabricated by removing a single phase of a binary aluminum-copper alloy. This selective phase dissolution was carried out an Al-Al2Cu eutectic alloy of the Al-Cu binary system and additionally for two hypereutectic compositions. The porosity of the material depends on the microstructure formed upon solidification. For this reason, several solidification methods were studied to define the most convenient in terms of uniformity and refinement of the average pore and ligament sizes. The samples were corroded in a 10% v/v NaOH aqueous solution, which demonstrated to be the most convenient in terms of time involved and resulting porosity conditions after the corrosion process. The porosity was measured through analysis of secondary electron images. The effectiveness of the process was verified using X-ray diffraction, which showed that, under the proposed methodology, there was complete removal of one of the phases, namely the aluminum one. Full article
(This article belongs to the Special Issue Nanoporous Metals)
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Open AccessArticle Skeletonization, Geometrical Analysis, and Finite Element Modeling of Nanoporous Gold Based on 3D Tomography Data
Metals 2018, 8(4), 282; https://doi.org/10.3390/met8040282
Received: 12 March 2018 / Revised: 12 April 2018 / Accepted: 16 April 2018 / Published: 19 April 2018
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Abstract
Various modeling approaches simplify and parametrize the complex network structure of nanoporous gold (NPG) for studying the structure–property relationship based on artificially generated structures. This paper presents a computational efficient and versatile finite element method (FEM) beam model that is based on skeletonization
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Various modeling approaches simplify and parametrize the complex network structure of nanoporous gold (NPG) for studying the structure–property relationship based on artificially generated structures. This paper presents a computational efficient and versatile finite element method (FEM) beam model that is based on skeletonization and diameter information derived from the original 3D focused ion beam-scanning electron microscope (FIB-SEM) tomography data of NPG. The geometrical skeleton network is thoroughly examined for a better understanding of the NPG structure. A skeleton FEM beam model is derived that can predict the macroscopic mechanical behavior of the material. Comparisons between the mechanical response of this skeleton beam model and a solid FEM model are conducted. Results showed that the biggest-sphere diameter algorithm implemented in the open-source software FIJI, commonly used for geometrical analysis of microstructural data, overestimates the diameter of the curved NPG ligaments. The larger diameters lead to a significant overestimation of macroscopic stiffness and strength by the skeleton FEM beam model. For a parabolic shaped ligament with only 20% variation in its diameter, a factor of more than two was found in stiffness. It is concluded that improved algorithms for image processing are needed that provide accurate diameter information along the ligament axis. Full article
(This article belongs to the Special Issue Nanoporous Metals)
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Open AccessArticle Chemical Dealloying Synthesis of CuS Nanowire-on-Nanoplate Network as Anode Materials for Li-Ion Batteries
Metals 2018, 8(4), 252; https://doi.org/10.3390/met8040252
Received: 7 March 2018 / Revised: 3 April 2018 / Accepted: 4 April 2018 / Published: 9 April 2018
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Abstract
CuS is a metal sulfide anode material used in constructing lithium ion batteries (LIBs) with great promise. However, its practical application is limited by rapid capacity decline, poor cycling, and rate performance. In this work, the CuS nanowire-on-nanoplate network is synthesized through an
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CuS is a metal sulfide anode material used in constructing lithium ion batteries (LIBs) with great promise. However, its practical application is limited by rapid capacity decline, poor cycling, and rate performance. In this work, the CuS nanowire-on-nanoplate network is synthesized through an improved dealloying method under two contrasting reaction temperatures. When used as an LIB anode, the as-obtained CuS network exhibits superior cycling performance (420 mAh·g−1 retained after 100 cycles at 0.2 C). When at 3 C, it still delivers a capacity of around 350 mAh·g−1. The improved electrochemical performances of the CuS anode should be attributed to the well-designed nanowire-on-nanoplate network structure in which the introduction of nanowires improves Li storage sites, shortens Li-ion diffusion distance, enhances the conductivity of active materials, and offers multiscale spaces for buffering the volume variation. The fabrication route adopted in this paper has an important significance for developing the dealloying technique and designing more suitable anode structures for LIBs. Full article
(This article belongs to the Special Issue Nanoporous Metals)
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Open AccessFeature PaperCommunication Bottom-up Synthesis of Porous NiMo Alloy for Hydrogen Evolution Reaction
Metals 2018, 8(2), 83; https://doi.org/10.3390/met8020083
Received: 15 October 2017 / Revised: 22 December 2017 / Accepted: 20 January 2018 / Published: 23 January 2018
Cited by 3 | PDF Full-text (3175 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Bottom-up synthesis of porous NiMo alloy reduced by NiMoO4 nanofibers was systematically investigated to fabricate non-noble metal porous electrodes for hydrogen production. The different annealing temperatures of NiMoO4 nanofibers under hydrogen atmosphere reveal that the 950 °C annealing temperature is key
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Bottom-up synthesis of porous NiMo alloy reduced by NiMoO4 nanofibers was systematically investigated to fabricate non-noble metal porous electrodes for hydrogen production. The different annealing temperatures of NiMoO4 nanofibers under hydrogen atmosphere reveal that the 950 °C annealing temperature is key for producing bicontinuous porous NiMo alloy without oxide phases. The porous NiMo alloy acts as a cathode in electrical water splitting, which demonstrates not only almost identical catalytic activity with commercial Pt/C in 1.0 M KOH solution, but also superb stability for 12 days at an electrode potential of −200 mV vs. reversible hydrogen electrode (RHE). Full article
(This article belongs to the Special Issue Nanoporous Metals)
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Open AccessCommunication Synthesis of Metastable Au-Fe Alloy Using Ordered Nanoporous Silica as a Hard Template
Metals 2018, 8(1), 17; https://doi.org/10.3390/met8010017
Received: 24 November 2017 / Revised: 22 December 2017 / Accepted: 23 December 2017 / Published: 30 December 2017
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Abstract
Nanoporous Au-Fe alloy was synthesized via a wet chemistry route using ordered nanoporous silica as a hard template. The nanoporous Au-Fe consisted of aligned arrays of nanopores that were uniform in composition and ordered in hexagonal lattice, whereas Au-Fe nanoparticles synthesized without templates
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Nanoporous Au-Fe alloy was synthesized via a wet chemistry route using ordered nanoporous silica as a hard template. The nanoporous Au-Fe consisted of aligned arrays of nanopores that were uniform in composition and ordered in hexagonal lattice, whereas Au-Fe nanoparticles synthesized without templates exhibited broad dispersions in the chemical composition and/or particle size. Nanoporous Au-Fe has potential for applications as catalysts and/or adsorbents because of the large specific surface area of 81.2 m2·g−1 and high pore volume of 0.56 cm3·g−1. Full article
(This article belongs to the Special Issue Nanoporous Metals)
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Open AccessFeature PaperCommunication In-Situ TEM Study of a Nanoporous Ni–Co Catalyst Used for the Dry Reforming of Methane
Metals 2017, 7(10), 406; https://doi.org/10.3390/met7100406
Received: 24 August 2017 / Revised: 21 September 2017 / Accepted: 28 September 2017 / Published: 1 October 2017
Cited by 1 | PDF Full-text (12173 KB) | HTML Full-text | XML Full-text
Abstract
We performed in-situ transmission electron microscopy (TEM) on a dealloyed nanoporous NiCo catalyst used for the dry reforming of methane (DRM) to investigate the origin of the catalytic activity and structural durability. The in-situ observations and local chemical analysis indicated that the DRM
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We performed in-situ transmission electron microscopy (TEM) on a dealloyed nanoporous NiCo catalyst used for the dry reforming of methane (DRM) to investigate the origin of the catalytic activity and structural durability. The in-situ observations and local chemical analysis indicated that the DRM induced chemical demixing of Ni and Co accompanied by grain refinement, implying possible “synergic effects” in a general bimetallic NiCo catalyst when used for the DRM. Full article
(This article belongs to the Special Issue Nanoporous Metals)
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