[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.

http://repository.ust.hk/ir/bitstream/1783.1-77094/1/acs.chemrev.5b00462_withlink.pdf

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

TiO(2) is one of the most studied compounds in materials science. Owing to some outstanding properties it is used for instance in photocatalysis, dye-sensitized solar cells, and biomedical devices. In 1999, first reports showed the feasibility to grow highly ordered arrays of TiO(2) nanotubes by a simple but optimized electrochemical anodization of a titanium metal sheet. This finding stimulated intense research activities that focused on growth, modification, properties, and applications of these one-dimensional nanostructures. This review attempts to cover all these aspects, including underlying principles and key functional features of TiO(2), in a comprehensive way and also indicates potential future directions of the field.

TiO2 nanotubes: synthesis and applications.

Interfacial Charge Field in Hierarchical Yolk–Shell Nanocapsule Enables Efficient Immobilization and Catalysis of Polysulfides Conversion

The ingenious design of a freestanding flexible electrode brings the possibility for power sources in emerging wearable electronic devices Here, reduced graphene oxide (rGO) wraps carbon nanotubes (CNTs) and rGO tightly surrounded by MnO2 nanosheets, forming a 3D multilevel porous conductive structure via vacuum freeze-drying The sandwich-like architecture possesses multiple functions as a flexible anode for lithium-ion batteries Micrometer-sized pores among the continuously waved rGO layers could extraordinarily improve ion diffusion Nano-sized pores among the MnO2 nanosheets and CNT/rGO@MnO2 particles could provide vast accessible active sites and alleviate volume change The tight connection between MnO2 and carbon skeleton could facilitate electron transportation and enhance structural stability Due to the special structure, the rGO-wrapped CNT/rGO@MnO2 porous film as an anode shows a high capacity, excellent rate performance, and superior cycling stability (13442 mAh g-1 over 630 cycles at 2 A g-1 , 6085 mAh g-1 over 1000 cycles at 75 A g-1 ) Furthermore, the evolutions of microstructure and chemical valence occurring inside the electrode after cycling are investigated to illuminate the structural superiority for energy storage The excellent electrochemical performance of this freestanding flexible electrode makes it an attractive candidate for practical application in flexible energy storage

Flexible Graphene-Wrapped Carbon Nanotube/Graphene@MnO2 3D Multilevel Porous Film for High-Performance Lithium-Ion Batteries.

To meet the demands of strengthening microwave absorption capability, self-assembly nanoparticles (NP) with flexible morphology and abundant interfaces are important and their synthesis remains great challenge. In this paper, cobalt monoxide (CoO) nanostructures with octahedral and 3-dimensional (3D) nano-flower morphologies were controllably synthesized by decomposition of cobalt acetylacetonate at 280 °C, chelated with dual-surfactants of oleylamine and oleic acid with various volume ratios (10 : 1–7 : 4). The basic structural units of both octahedrons and 3D nano-flowers are octahedral CoO NP, which was demonstrated by advanced 3D transmission electron microscopy tomography. Dependency of the tunable microwave absorption properties on the 3D geometric morphologies of CoO NP was well established. The absorption bandwidth with a reflection loss (RL) of less than −10 dB is larger than 6 GHz for both octahedrons and nano-flowers. Compared to the spherical CoO NP, the octahedral nano-flowers have highly enhanced microwave absorption capability. Moreover, the maximum RL peak of the nano-flower CoO NP reached as high as −37 dB at 10.5 GHz, compared to that of −17 dB at 12 GHz for the octahedral CoO NP and −6.3 dB at 7.5 GHz for the spherical CoO NP. These results indicate a remarkable dependency of the dielectric polarization absorption and magnetic coupling absorption on the geometric morphology of CoO nano-architecture. It can be supposed from our findings that various morphologies of self-assembling CoO NP might become an effective path to achieve high-performance microwave absorption for electromagnetic shielding and stealth camouflage applications.

Morphology-dominant microwave absorption enhancement and electron tomography characterization of CoO self-assembly 3D nano-flowers

Superstructure silver micro-tube composites for ultrahigh electromagnetic wave shielding

Rational designing of one-dimensional (1D) magnetic alloy to facilitate electromagnetic (EM) wave attenuation capability in low-frequency (2-6 GHz) microwave absorption field is highly desired but remains a significant challenge. In this study, a composite EM wave absorber made of a FeCoNi medium-entropy alloy embedded in a 1D carbon matrix framework is rationally designed through an improved electrospinning method. The 1D-shaped FeCoNi alloy embedded composite demonstrates the high-density and continuous magnetic network using off-axis electronic holography technique, indicating the excellent magnetic loss ability under an external EM field. Then, the in-depth analysis shows that many factors, including 1D anisotropy and intrinsic physical features of the magnetic medium-entropy alloy, primarily contribute to the enhanced EM wave absorption performance. Therefore, the fabricated EM wave absorber shows an increasing effective absorption band of 1.3 GHz in the low-frequency electromagnetic field at an ultrathin thickness of 2 mm. Thus, this study opens up a new method for the design and preparation of high-performance 1D magnetic EM absorbers. 

https://link.springer.com/content/pdf/10.1007/s40820-022-00920-7.pdf

Renchao Che

Papers

Interfacial Charge Field in Hierarchical Yolk–Shell Nanocapsule Enables Efficient Immobilization and Catalysis of Polysulfides Conversion

Flexible Graphene-Wrapped Carbon Nanotube/Graphene@MnO2 3D Multilevel Porous Film for High-Performance Lithium-Ion Batteries.

Morphology-dominant microwave absorption enhancement and electron tomography characterization of CoO self-assembly 3D nano-flowers

Superstructure silver micro-tube composites for ultrahigh electromagnetic wave shielding

One-Dimensional Magnetic FeCoNi Alloy Toward Low-Frequency Electromagnetic Wave Absorption