ACS Materials Au

Journal Information
ISSN / EISSN : 2694-2461 / 2694-2461
Published by: American Chemical Society (ACS) (10.1021)
Total articles ≅ 20
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Karleena Rybacki, Stacy A. Love, Bailey Blessing, Abneris Morales, Emily McDermott, Kaylyn Cai, ,
Published: 25 October 2021
Abstract:
In this study, the structural, thermal, and morphological properties of biocomposite films composed of wool keratin mixed with cellulose and regenerated with ionic liquids and various coagulation agents were characterized and explored. These blended films exhibit different physical and thermal properties based on the polymer ratio and coagulation agent type in the fabrication process. Thus, understanding their structure and molecular interaction will enable an understanding of how the crystallinity of cellulose can be modified in order to understand the formation of protein secondary structures. The thermal, morphological, and physiochemical properties of the biocomposites were investigated by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray scattering. Analysis of the results suggests that both the wool keratin and the cellulose structures can be manipulated during dissolution and regeneration. Specifically, the β-sheet content in wool keratin increases with the increase of the ethanol solution concentration during the coagulation process; likewise, the cellulose crystallinity increases with the increase of the hydrogen peroxide concentration via coagulation. These findings suggest that the different molecular interactions in a biocomposite can be tuned systematically. This can lead to developments in biomaterial research including advances in natural based electrolyte batteries, as well as implantable bionics for medical research.
Jaehyun Kim, Sungkyun Choi, Jinhyuk Cho, ,
Published: 25 October 2021
Abstract:
Single-atom catalysts (SACs) have recently emerged as the ultimate solution for overcoming the limitations of traditional catalysts by bridging the gap between homogeneous and heterogeneous catalysts. Atomically dispersed identical active sites enable a maximal atom utilization efficiency, high activity, and selectivity toward the wide range of electrochemical reactions, superior structural robustness, and stability over nanoparticles due to strong atomic covalent bonding with supports. Mononuclear active sites of SACs can be further adjusted by engineering with multicomponent elements, such as introducing dual-metal active sites or additional neighbor atoms, and SACs can be regarded as multicomponent SACs if the surroundings of the active sites or the active sites themselves consist of multiple atomic elements. Multicomponent engineering offers an increased combinational diversity in SACs and unprecedented routes to exceed the theoretical catalytic performance limitations imposed by single-component scaling relationships for adsorption and transition state energies of reactions. The precisely designed structures of multicomponent SACs are expected to be responsible for the synergistic optimization of the overall electrocatalytic performance by beneficially modulating the electronic structure, the nature of orbital filling, the binding energy of reaction intermediates, the reaction pathways, and the local structural transformations. This Review demonstrates these synergistic effects of multicomponent SACs by highlighting representative breakthroughs on electrochemical conversion reactions, which might mitigate the global energy crisis of high dependency on fossil fuels. General synthesis methods and characterization techniques for SACs are also introduced. Then, the perspective on challenges and future directions in the research of SACs is briefly summarized. We believe that careful tailoring of multicomponent active sites is one of the most promising approaches to unleash the full potential of SACs and reach the superior catalytic activity, selectivity, and stability at the same time, which makes SACs promising candidates for electrocatalysts in various energy conversion reactions.
Sungwoo Kang, Seungwu Han,
Published: 21 October 2021
Abstract:
The luminescence line shape is an important feature of semiconductor quantum dots (QDs) and affects performance in various optical applications. Here, we report a first-principles method to predict the luminescence spectrum of thousands of atom QDs. In our approach, neural network potential calculations are combined with density functional theory calculations to describe exciton–phonon coupling (EPC). Using the calculated EPC, the luminescence spectrum is evaluated within the Franck–Condon approximation. Our approach results in the luminescence line shape for an InP/ZnSe core/shell QD (3406 atoms) that exhibits excellent agreement with the experiments. From a detailed analysis of EPC, we reveal that the coupling of both acoustic and optical phonons to an exciton are important in determining the spectral line shapes of core/shell QDs, which is in contrast with previous studies. On the basis of the present simulation results, we provide guidelines for designing high-performance core/shell QDs with ultrasharp emission spectra.
Jesimiel Glaycon Rodrigues Antonio, Jefferson Honorio Franco, Paula Z. Almeida, Thiago S. Almeida, Maria de Lourdes Teixeira de Morais Polizeli, ,
Published: 18 October 2021
Abstract:
We report a hybrid catalytic system containing metallic PtSn nanoparticles deposited on multiwalled carbon nanotubes (Pt65Sn35/MWCNTs), prepared by the microwave-assisted method, coupled to the enzyme oxalate oxidase (OxOx) for complete ethylene glycol (EG) electrooxidation. Pt65Sn35/MWCNTs, without OxOx, showed good electrochemical activity toward EG oxidation and all the byproducts. Pt65Sn35/MWCNTs cleaved the glyoxilic acid C–C bond, producing CO2 and formic acid, which was further oxidized at the electrode. Concerning EG oxidation, the catalytic activity of the hybrid system (Pt65Sn35/MWCNTs+OxOx) was twice the catalytic activity of Pt65Sn35/MWCNTs. Long-term electrolysis revealed that Pt65Sn35/MWCNTs+OxOx was much more active for EG oxidation than Pt65Sn35/MWCNTs: the charge increased by 65%. The chromatographic results proved that Pt65Sn35/MWCNTs+OxOx collected all of the 10 electrons per molecule of the fuel and was able to catalyze EG oxidation to CO2 due to the associative oxidation between the metallic nanoparticles and the enzymatic pathway. Overall, Pt65Sn35/MWCNTs+OxOx proved to be a promising system to enhance the development of enzymatic biofuel cells for further application in the bioelectrochemistry field.
Published: 13 October 2021
Abstract:
Superomniphobic surfaces that can self-repair physical damage are desirable for sustainable performance over time in many practical applications that include self-cleaning, corrosion resistance, and protective gears. However, fabricating such self-repairing superomniphobic surfaces has thus far been a challenge because it necessitates the regeneration of both low-surface-energy materials and hierarchical topography. Herein, a water-responsive self-repairing superomniphobic film is reported by utilizing cross-linked hydroxypropyl cellulose (HPC) composited with silica (SiO2) nanoparticles (HPC-SiO2) that is treated with a low-surface-energy perfluorosilane. The film can repair physical damage (e.g., a scratch) in approximately 10 s by regenerating its hierarchical topography and low-surface-energy material upon the application of water vapor. The repaired region shows an almost complete recovery of its inherent superomniphobic wettability and mechanical hardness. The repairing process is driven by the reversible hydrogen bond between the hydroxyl (−OH) groups which can be dissociated upon exposure to water vapor. This results in a viscous flow of the HPC-SiO2 film into the damaged region. A mathematical model composed of viscosity and surface tension of the HPC-SiO2 film can describe the experimentally measured viscous flow with reasonable accuracy. Finally, we demonstrate that the superomniphobic HPC-SiO2 film can repair physical damage by a water droplet pinned on a damaged area or by sequential rolling water droplets.
Jingfeng Zheng, Brian Perry,
Published: 30 September 2021
Abstract:
Antiperovskites of composition M3AB (M = Li, Na, K; A = O; B = Cl, Br, I, NO2, etc.) have recently been investigated as solid-state electrolytes for all-solid-state batteries. Inspired by the impressive ionic conductivities of Li3OCl0.5Br0.5 and Na3OBH4 as high as 10–3 S/cm at room temperature, many variants of antiperovskite-based Li-ion and Na-ion conductors have been reported, and K-ion antiperovskites are emerging. These materials exhibit low melting points and thus have the advantages of easy processing into films and intimate contacts with electrodes. However, there are also issues in interpreting the stellar materials and reproducing their high ionic conductivities. Therefore, we think a critical review can be useful for summarizing the current results, pointing out the potential issues, and discussing best practices for future research. In this critical review, we first overview the reported compositions, structural stabilities, and ionic conductivities of antiperovskites. We then discuss the different conduction mechanisms that have been proposed, including the partial melting of cations and the paddlewheel mechanism for cluster anions. We close by reviewing the use of antiperovskites in batteries and suggest some practices for the community to consider.
, Iryna Zelenina, Quirin E. Stahl, , Primož Koželj, Mitja Krnel, Ulrich Burkhardt, Igor Veremchuk, , Wilder Carrillo-Cabrera, et al.
Published: 20 September 2021
Abstract:
The compound IrGa3 was synthesized by direct reaction of the elements. It is formed as a high-temperature phase in the Ir-Ga system. Single-crystal X-ray diffraction analysis confirms the tetragonal symmetry (space group P42/mnm, No. 136) with a = 6.4623(1) Å and c = 6.5688(2) Å and reveals strong disorder in the crystal structure, reflected in the huge values and anisotropy of the atomic displacement parameters. A model for the real crystal structure of ht-IrGa3 is derived by the split-position approach from the single-crystal X-ray diffraction data and confirmed by an atomic-resolution transmission electron microscopy study. Temperature-dependent electrical resistivity measurements evidence semiconductor behavior with a band gap of 30 meV. A thermoelectric characterization was performed for ht-IrGa3 and for the solid solution IrGa3–xZnx.
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