scholarly journals Methods to Generate Structurally Hierarchical Architectures in Nanoporous Coinage Metals

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1440
Author(s):  
Palak Sondhi ◽  
Keith J. Stine
Keyword(s):  
Functional Materials ◽  
Material Design ◽  
Nanoporous Gold ◽  
Porous Metals ◽  
Transport Pathways ◽  
Structural Hierarchy ◽  
Enhanced Sensitivity ◽  
Coinage Metals ◽  
Hierarchical Architectures ◽  
Rapid Transport

The fundamental essence of material design towards creating functional materials lies in bringing together the competing aspects of a large specific surface area and rapid transport pathways. The generation of structural hierarchy on distinct and well-defined length scales has successfully solved many problems in porous materials. Important applications of these hierarchical materials in the fields of catalysis and electrochemistry are briefly discussed. This review summarizes the recent advances in the strategies to create a hierarchical bicontinuous morphology in porous metals, focusing mainly on the hierarchical architectures in nanoporous gold. Starting from the traditional dealloying method and subsequently moving to other non-traditional top-down and bottom-up manufacturing processes including templating, 3D printing, and electrodeposition, this review will thoroughly examine the chemistry of creating hierarchical nanoporous gold and other coinage metals. Finally, we conclude with a discussion about the future opportunities for the advancement in the methodologies to create bimodal structures with enhanced sensitivity.

scholarly journals Design of Heat-Conductive hBN–PMMA Composites by Electrostatic Nano-Assembly

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 134 ◽  
Author(s):  
Atsushi Yokoi ◽  
Wai Kian Tan ◽  
Taichi Kuroda ◽  
Go Kawamura ◽  
Atsunori Matsuda ◽  
...  
Keyword(s):  
Composite Materials ◽  
Hexagonal Boron Nitride ◽  
Functional Materials ◽  
Polymeric Materials ◽  
Material Design ◽  
Heat Conducting ◽  
Matrix Composites ◽  
Assembly Method ◽  
Functional Additives ◽  
Energy Consuming

Micro/nanoscale design of composite materials enables alteration of their properties for advanced functional materials. One of the biggest challenges in material design is the controlled decoration of composite materials with the desired functional additives. This study reports on and demonstrates the homogeneous decoration of hexagonal boron nitride (hBN) on poly(methylmethacrylate) (PMMA) and vice versa. The formation of the composite materials was conducted via a low environmental load and a low-energy-consuming, electrostatic nano-assembly method which also enabled the efficient usage of nano-sized additives. The hBN/PMMA and PMMA/hBN composites were fabricated in various size combinations that exhibited percolated and layer-oriented structures, respectively. The thermal conductivity behaviors of hBN/PMMA and PMMA/hBN composites that exhibited good microstructure were compared. The results showed that microstructural design of the composites enabled the modification of their heat-conducting property. This novel work demonstrated the feasibility of fabricating heat-conductive PMMA matrix composites with controlled decoration of hBN sheets, which may provide a platform for further development of heat-conductive polymeric materials.

A facile electrochemical approach to fabricate a nanoporous gold film electrode and its electrocatalytic activity towards dissolved oxygen reduction

2015 ◽  
Vol 17 (43) ◽  
pp. 28510-28514 ◽  
Author(s):  
Anandhakumar Sukeri ◽  
Lucas Patricio Hernández Saravia ◽  
Mauro Bertotti
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Reduction ◽  
Electrocatalytic Activity ◽  
Gold Film ◽  
Reducing Agents ◽  
Nanoporous Gold ◽  
Film Electrode ◽  
Enhanced Sensitivity ◽  
Electrochemical Approach ◽  
Low Overpotential

NPGF electrode was fabricated in absence of alloys, templates & chemical reducing agents and its electrocatalytic activity towards DO reduction was achieved at very low overpotential with enhanced sensitivity.

scholarly journals Strain-driven autonomous control of cation distribution for artificial ferroelectrics

2021 ◽  
Vol 7 (18) ◽  
pp. eabd7394
Author(s):  
Changhee Sohn ◽  
Xiang Gao ◽  
Rama K. Vasudevan ◽  
Sabine M. Neumayer ◽  
Nina Balke ◽  
...  
Keyword(s):  
Functional Materials ◽  
Material Design ◽  
Mechanical Deformation ◽  
Strain Engineering ◽  
New Materials ◽  
Crystallographic Position ◽  
Atomic Position ◽  
Steep Ascent ◽  
Specific Position ◽  
Synthesis Methodology

In past few decades, there have been substantial advances in theoretical material design and experimental synthesis, which play a key role in the steep ascent of developing functional materials with unprecedented properties useful for next-generation technologies. However, the ultimate goal of synthesis science, i.e., how to locate atoms in a specific position of matter, has not been achieved. Here, we demonstrate a unique way to inject elements in a specific crystallographic position in a composite material by strain engineering. While the use of strain so far has been limited for only mechanical deformation of structures or creation of elemental defects, we show another powerful way of using strain to autonomously control the atomic position for the synthesis of new materials and structures. We believe that our synthesis methodology can be applied to wide ranges of systems, thereby providing a new route to functional materials.

scholarly journals Anatase-Wrapped Rutile Nanorods as an Effective Electron Collector in Hybrid Photoanodes for Visible Light-Driven Oxygen Evolution

2021 ◽  
Vol 9 ◽  
Author(s):  
Ruihao Gong ◽  
Dariusz Mitoraj ◽  
Robert Leiter ◽  
Manuel Mundszinger ◽  
Alexander K. Mengele ◽  
...  
Keyword(s):  
Visible Light ◽  
Surface Area ◽  
Oxygen Evolution ◽  
Functional Materials ◽  
Transport Pathways ◽  
Effective Electron ◽  
Faradaic Efficiency ◽  
Interfacial Engineering ◽  
Visible Light Driven ◽  
Anatase Nanoparticles

Arrays of single crystal TiO2 rutile nanorods (RNRs) appear highly promising as electron-collecting substrates in hybrid photoanodes as the RNRs offer direct charge carriers transport pathways, contrary to the conventional electrodes prepared from TiO2 powders that suffer from the numerous charge traps at the grain boundaries. However, the specific surface area of the nanorods is highly limited by their smooth morphology, which might be detrimental in view of utilizing the RNR as a substrate for immobilizing other functional materials. In this study, we developed a novel anatase-wrapped RNR (ARNR) material fabricated by a facile seed layer-free hydrothermal method. The ARNR comprises polycrystalline anatase nanoparticles formed on the surface of RNR, resulting in a large surface area that provides more deposition sites compared to the bare nanorods. Herein, we functionalize ARNR and RNR electrodes with polymeric carbon nitride (CNx) coupled with a CoO(OH)x cocatalyst for dioxygen evolution. The anatase wrapping of the rutile nanorod scaffold is found to be crucial for effective deposition of CNx and for improved photoanode operation in visible light-driven (λ > 420 nm) oxygen evolution, yielding a significant enhancement of photocurrent (by the factor of ∼3.7 at 1.23 V vs. RHE) and faradaic efficiency of oxygen evolution (by the factor of ∼2) as compared to photoanodes without anatase interlayer. This study thus highlights the importance of careful interfacial engineering in constructing photoelectrocatalytic systems for solar energy conversion and paves the way for the use of ARNR-based electron collectors in further hybrid and composite photochemical architectures for solar fuel production.

scholarly journals Anisotropic Magnetism in Gradient Porous Carbon Composite Aerogels

2021 ◽  
Vol 7 (1) ◽  
pp. 22
Author(s):  
Jochen Bahner ◽  
Nicolas Hug ◽  
Sebastian Polarz
Keyword(s):  
Porous Carbon ◽  
High Surface ◽  
Sol Gel ◽  
Functional Materials ◽  
Material Design ◽  
Carbon Composite ◽  
Functionally Graded ◽  
Carbon Aerogels ◽  
Pore Sizes ◽  
Composite Aerogels

Porosity is of high importance for functional materials, as it allows for high surface areas and the accessibility of materials. While the fundamental interplay between different pore sizes and functionalities is quite well understood, few studies on gradually changing properties in a material exist. To date, only a few examples of such materials have been synthesized successfully. Herein, we present a facile method for synthesizing macroscopic carbon aerogels with locally changing pore sizes and functionalities. We used ultracentrifugation to fractionate differently functionalized and sized polystyrene nanoparticles. The assembly into gradient templates was conducted in a resorcinol–formaldehyde (RF) sol, which acted as a liquid phase and carbon precursor. We show that the modification of nanoparticles and a sol–gel precursor is a powerful tool for introducing dopants (sulfur and phosphorous) and metal nanoparticles (e.g., Ni) into gradient porous carbons formed during the carbonization of the RF sol. Understanding the underlying interactions between particles and precursors will lead to a plethora of possibilities in the material design of complex functionally graded materials. We showed this by exchanging parts of the template with magnetite–polystyrene composites as templating nanoparticles. This led to the incorporation of magnetite nanoparticles in the formed gradient porous carbon aerogels. Finally, gradually increasing concentrations of magnetite were obtained, ultimately leading to macroscopic carbon aerogels with locally changing magnetic properties, while the graded porosity was maintained.

From design to applications of stimuli-responsive hydrogel strain sensors

2020 ◽  
Vol 8 (16) ◽  
pp. 3171-3191 ◽  
Author(s):  
Dong Zhang ◽  
Baiping Ren ◽  
Yanxian Zhang ◽  
Lijian Xu ◽  
Qinyuan Huang ◽  
...  
Keyword(s):  
Functional Materials ◽  
Material Design ◽  
Strain Sensors ◽  
Stimuli Responsive ◽  
Human Machine Interfaces

Stimuli-responsive hydrogel strain sensors that synergize the advantages of both hydrogel and smart functional materials have attracted increasing interest from material design to emerging applications in health monitors and human–machine interfaces.

scholarly journals Applications of Synthetic Biology in Materials Science

2018 ◽  
Vol 2 (1) ◽  
pp. 14-18
Author(s):  
Chao Shang ◽  
Keyword(s):  
Synthetic Biology ◽  
High Efficiency ◽  
Materials Science ◽  
Low Cost ◽  
Functional Materials ◽  
Material Design ◽  
Inorganic Materials ◽  
Advanced Materials ◽  
Human Society ◽  
Material Sciences

Materials are the basis for human being survival and social development. To keep abreast with the increasing needs from all aspects of human society, there are huge needs in the development of advanced materials as well as high-efficiency but low-cost manufacturing strategies that are both sustainable and tunable. Synthetic biology, a new engineering principle taking gene regulation and engineering design as the core, greatly promotes the development of life sciences. This discipline has also contributed to the development of material sciences and will continuously bring new ideas to future new material design. In this paper, we review recent advances in applications of synthetic biology in material sciences, with the focus on how synthetic biology could enable synthesis of new polymeric biomaterials and inorganic materials, phage display and directed evolution of proteins relevant to materials development, living functional materials, engineered bacteria-regulated artificial photosynthesis system as well as applications of gene circuits for material sciences.

Reversible Strain in Porous Metals Charged in Electrolytes

2005 ◽  
Vol 876 ◽  
Author(s):  
Dominik Kramer ◽  
Raghavan Nadar Viswanath ◽  
Smrutiranjan Parida ◽  
Jörg Weissmüller
Keyword(s):  
Surface Charge ◽  
Composite Structures ◽  
General Concept ◽  
Nanoporous Gold ◽  
Surface Strain ◽  
Nanocrystalline Powders ◽  
Metal Foil ◽  
Porous Metals ◽  
Pt Alloy ◽  
Nanoporous Metals

AbstractNanoporous metal samples with millimetre size were prepared either by compacting nanocrystalline powders or by dealloying, the dissolution of the less noble metal(s) of an alloy. The samples were immersed in an electrolyte, and their length was measured as a function of the applied potential in-situ in a dilatometer. The results obtained for nanocrystalline platinum, nanoporous gold and for gold platinum alloys show that the length varies in dependence of the surface charge. The strain amplitude of nanocrystalline platinum was 0.15%, and even larger strains have been measured using an Au-Pt alloy. This strain is comparable to commercial piezoceramics, but it is achieved using smaller voltages.The strain measured for nanoporous gold prepared by dealloying was smaller than that mainly due to the larger structure size (20 nm structure size compared to 6 nm Pt crystallite size), but in the case of gold, it was possible to prepare stable composite structures of a metal foil and of the nanoporous gold. If such a bimetallic foil is charged, it is found to bend. Due to the mechanical amplification of the contraction or expansion of the nanoporous part of the foil, it was possible to observe the effect of electric charges on the surface stress of metals directly with the naked eye for the first time.These results demonstrate that nanoporous metals might be useful for actuator applications and for the study of surface strain effects. Furthermore, they are the first realization of a general concept that suggests that most of the properties of conducting nanomaterials can be tuned by controlling the surface charge.

Sign in / Sign up

Export Citation Format

Share Document