Research

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13 pages, 7361 KiB

Open AccessArticle

Bio-Template Synthesis of V₂O₃@Carbonized Dictyophora Composites for Advanced Aqueous Zinc-Ion Batteries

by Wei Zhou, Guilin Zeng, Haotian Jin, Shaohua Jiang, Minjie Huang, Chunmei Zhang and Han Chen

Molecules 2023, 28(5), 2147; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28052147 - 24 Feb 2023

Cited by 47 | Viewed by 1989

Abstract

In terms of new-generation energy-storing devices, aqueous zinc-ion batteries (AZIBs) are becoming the prime candidates because of their inexpensive nature, inherent safety, environmental benignity and abundant resources. Nevertheless, due to a restrained selection of cathodes, AZIBs often perform unsatisfactorily under long-life cycling and [...] Read more.

In terms of new-generation energy-storing devices, aqueous zinc-ion batteries (AZIBs) are becoming the prime candidates because of their inexpensive nature, inherent safety, environmental benignity and abundant resources. Nevertheless, due to a restrained selection of cathodes, AZIBs often perform unsatisfactorily under long-life cycling and high-rate conditions. Consequently, we propose a facile evaporation-induced self-assembly technique for preparing V₂O₃@carbonized dictyophora (V₂O₃@CD) composites, utilizing economical and easily available biomass dictyophora as carbon sources and NH₄VO₃ as metal sources. When assembled in AZIBs, the V₂O₃@CD exhibits a high initial discharge capacity of 281.9 mAh g⁻¹ at 50 mA g⁻¹. The discharge capacity is still up to 151.9 mAh g⁻¹ after 1000 cycles at 1 A g⁻¹, showing excellent long-cycle durability. The extraordinary high electrochemical effectiveness of V₂O₃@CD could be mainly attributed to the formation of porous carbonized dictyophora frame. The formed porous carbon skeleton can ensure efficient electron transport and prevent V₂O₃ from losing electrical contact due to volume changes caused by Zn²⁺ intercalation/deintercalation. The strategy of metal-oxide-filled carbonized biomass material may provide insights into developing high-performance AZIBs and other potential energy storage devices, with a wide application range. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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11 pages, 3282 KiB

Open AccessEditor’s ChoiceArticle

Efficient Hydrogen and Oxygen Evolution Catalysis Using 3D-Structured Nickel Phosphosulfide Nanosheets in Alkaline Media

by Lei Lin, Qiang Fu, Junbei Hu, Ran Wang and Xianjie Wang

Molecules 2023, 28(1), 315; https://doi.org/10.3390/molecules28010315 - 30 Dec 2022

Cited by 2 | Viewed by 1833

Abstract

Water electrolysis offers a zero-carbon route to generate renewable energy conversion systems. Herein, a self-supported nickel phosphosulfide nanosheet (NS) electrocatalyst was fabricated at a low temperature on carbon cloth, which was then subjected to Ar etching to enhance its catalytic activity. Etching resulted [...] Read more.

Water electrolysis offers a zero-carbon route to generate renewable energy conversion systems. Herein, a self-supported nickel phosphosulfide nanosheet (NS) electrocatalyst was fabricated at a low temperature on carbon cloth, which was then subjected to Ar etching to enhance its catalytic activity. Etching resulted in better hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance than other samples, with overpotentials of 103.1 mV (at 10 mA cm⁻²) and 278.9 mV (at 50 mA cm⁻²), respectively. The characterization results confirmed that Ar etching created a thin amorphous layer around the NiPS₃ NSs, which increased the number of active sites and modulated their electronic structures. These 3D-structured NiPS₃ NSs and their subsequent Ar etching process show promise for applications in overall water splitting in alkaline media. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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11 pages, 2670 KiB

Open AccessArticle

Thermal, Mechanical and Dielectric Properties of Polyimide Composite Films by In-Situ Reduction of Fluorinated Graphene

by Yuyin Zhang, Tian Hu, Rubei Hu, Shaohua Jiang, Chunmei Zhang and Haoqing Hou

Molecules 2022, 27(24), 8896; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27248896 - 14 Dec 2022

Cited by 10 | Viewed by 1528

Abstract

Materials with outstanding mechanical properties and excellent dielectric properties are increasingly favored in the microelectronics industry. The application of polyimide (PI) in the field of microelectronics is limited because of the fact that PI with excellent mechanical properties does not have special features [...] Read more.

Materials with outstanding mechanical properties and excellent dielectric properties are increasingly favored in the microelectronics industry. The application of polyimide (PI) in the field of microelectronics is limited because of the fact that PI with excellent mechanical properties does not have special features in the dielectric properties. In this work, PI composite films with high dielectric properties and excellent mechanical properties are fabricated by in-situ reduction of fluorinated graphene (FG) in polyamide acid (PAA) composites. The dielectric permittivity of pure PI is 3.47 and the maximum energy storage density is 0.664 J/cm³ at 100 Hz, while the dielectric permittivity of the PI composite films reaches 235.74 under the same conditions, a 68-times increase compared to the pure PI, and the maximum energy storage density is 5.651, a 9-times increase compared to the pure PI films. This method not only solves the problem of the aggregation of the filler particles in the PI matrix and maintains the intrinsic excellent mechanical properties of the PI, but also significantly improves the dielectric properties of the PI. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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13 pages, 4394 KiB

Open AccessArticle

Electronic Structure-, Phonon Spectrum-, and Effective Mass- Related Thermoelectric Properties of PdXSn (X = Zr, Hf) Half Heuslers

by Bindu Rani, Aadil Fayaz Wani, Utkir Bahodirovich Sharopov, Lokanath Patra, Jaspal Singh, Atif Mossad Ali, A. F. Abd El-Rehim, Shakeel Ahmad Khandy, Shobhna Dhiman and Kulwinder Kaur

Molecules 2022, 27(19), 6567; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27196567 - 04 Oct 2022

Cited by 10 | Viewed by 1383

Abstract

We hereby discuss the thermoelectric properties of PdXSn(X = Zr, Hf) half Heuslers in relation to lattice thermal conductivity probed under effective mass (hole/electrons) calculations and deformation potential theory. In addition, we report the structural, electronic, mechanical, and lattice dynamics of these materials [...] Read more.

We hereby discuss the thermoelectric properties of PdXSn(X = Zr, Hf) half Heuslers in relation to lattice thermal conductivity probed under effective mass (hole/electrons) calculations and deformation potential theory. In addition, we report the structural, electronic, mechanical, and lattice dynamics of these materials as well. Both alloys are indirect band gap semiconductors with a gap of 0.91 eV and 0.82 eV for PdZrSn and PdHfSn, respectively. Both half Heusler materials are mechanically and dynamically stable. The effective mass of electrons/holes is (0.13/1.23) for Zr-type and (0.12/1.12) for Hf-kind alloys, which is inversely proportional to the relaxation time and directly decides the electrical/thermal conductivity of these materials. At 300K, the magnitude of lattice thermal conductivity observed for PdZrSn is 15.16 W/mK and 9.53 W/mK for PdHfSn. The highest observed ZT value for PdZrSn and PdHfSn is 0.32 and 0.4, respectively. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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11 pages, 1897 KiB

Open AccessArticle

Synthesis of Silver Nanoparticles-Modified Graphitic Carbon Nitride Nanosheets for Highly Efficient Photocatalytic Hydrogen Peroxide Evolution

by Jixiang Hou, Xu Zhang, Kaiwen Wang, Peijie Ma, Hanwen Hu, Xiyuan Zhou and Kun Zheng

Molecules 2022, 27(17), 5535; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27175535 - 28 Aug 2022

Cited by 6 | Viewed by 1661

Abstract

As a promising metal-free photocatalyst, graphitic carbon nitride (g-C₃N₄) is still limited by insufficient visible light absorption and rapid recombination of photogenerated carriers, resulting in low photocatalytic activity. Here, we adjusted the microstructure of the pristine bulk-g-C₃N [...] Read more.

As a promising metal-free photocatalyst, graphitic carbon nitride (g-C₃N₄) is still limited by insufficient visible light absorption and rapid recombination of photogenerated carriers, resulting in low photocatalytic activity. Here, we adjusted the microstructure of the pristine bulk-g-C₃N₄ (PCN) and further loaded silver (Ag) nanoparticles. Abundant Ag nanoparticles were grown on the thin-layer g-C₃N₄ nanosheets (CNNS), and the Ag nanoparticles decorated g-C₃N₄ nanosheets (Ag@CNNS) were successfully synthesized. The thin-layer nanosheet-like structure was not only beneficial for the loading of Ag nanoparticles but also for the adsorption and activation of reactants via exposing more active sites. Moreover, the surface plasmon resonance (SPR) effect induced by Ag nanoparticles enhanced the absorption of visible light by narrowing the band gap of the substrate. Meanwhile, the composite band structure effectively promoted the separation and transfer of carriers. Benefiting from these merits, the Ag@CNNS reached a superior hydrogen peroxide (H₂O₂) yield of 120.53 μmol/g/h under visible light irradiation in pure water (about 8.0 times higher than that of PCN), significantly surpassing most previous reports. The design method of manipulating the microstructure of the catalyst combined with the modification of metal nanoparticles provides a new idea for the rational development and application of efficient photocatalysts. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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11 pages, 2415 KiB

Open AccessArticle

Enhanced Electrochemical Water Oxidation Activity by Structural Engineered Prussian Blue Analogue/rGO Heterostructure

by Xiuyun An, Weili Zhu, Chunjuan Tang, Lina Liu, Tianwei Chen, Xiaohu Wang, Jianguo Zhao and Guanhua Zhang

Molecules 2022, 27(17), 5472; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27175472 - 25 Aug 2022

Cited by 1 | Viewed by 1302

Abstract

Prussian blue analogue (PBA), with a three-dimensional open skeleton and abundant unsaturated surface coordination atoms, attracts extensive research interest in electrochemical energy-related fields due to facile preparation, low cost, and adjustable components. However, it remains a challenge to directly employ PBA as an [...] Read more.

Prussian blue analogue (PBA), with a three-dimensional open skeleton and abundant unsaturated surface coordination atoms, attracts extensive research interest in electrochemical energy-related fields due to facile preparation, low cost, and adjustable components. However, it remains a challenge to directly employ PBA as an electrocatalyst for water splitting owing to their poor charge transport ability and electrochemical stability. Herein, the PBA/rGO heterostructure is constructed based on structural engineering. Graphene not only improves the charge transfer efficiency of the compound material but also provides confined growth sites for PBA. Furthermore, the charge transfer interaction between the heterostructure interfaces facilitates the electrocatalytic oxygen evolution reaction of the composite, which is confirmed by the results of the electrochemical measurements. The overpotential of the PBA/rGO material is only 331.5 mV at a current density of 30 mA cm⁻² in 1.0 M KOH electrolyte with a small Tafel slope of 57.9 mV dec⁻¹, and the compound material exhibits high durability lasting for 40 h. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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10 pages, 2018 KiB

Open AccessArticle

Atomic-Scale Tracking of Dynamic Nucleation and Growth of an Interfacial Lead Nanodroplet

by Xiaoxue Chang, Chunhao Sun, Leguan Ran, Ran Cai and Ruiwen Shao

Molecules 2022, 27(15), 4877; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27154877 - 30 Jul 2022

Viewed by 1106

Abstract

Revealing the evolutional pathway of the nucleation and crystallization of nanostructures at the atomic scale is crucial for understanding the complex growth mechanisms at the early stage of new substances and spices. Real-time discrimination of the atomic mechanism of a nanodroplet transition is [...] Read more.

Revealing the evolutional pathway of the nucleation and crystallization of nanostructures at the atomic scale is crucial for understanding the complex growth mechanisms at the early stage of new substances and spices. Real-time discrimination of the atomic mechanism of a nanodroplet transition is still a formidable challenge. Here, taking advantage of the high temporal and spatial resolution of transmission electron microscopy, the detailed growth pathway of Pb nanodroplets at the early stage of nucleation was directly observed by employing electron beams to induce the nucleation, growth, and fusion process of Pb nanodroplets based on PbTiO₃ nanowires. Before the nucleation of Pb nanoparticles, the atoms began to precipitate when they were irradiated by electrons, forming a local crystal structure, and then rapidly and completely crystallized. Small nanodroplets maintain high activity and high density and gradually grow and merge into stable crystals. The whole process was recorded and imaged by HRTEM in real time. The growth of Pb nanodroplets advanced through the classical path and instantaneous droplet coalescence. These results provide an atomic-scale insight on the dynamic process of solid/solid interface, which has implications in thin-film growth and advanced nanomanufacturing. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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12 pages, 1553 KiB

Open AccessArticle

Dielectric Properties Investigation of Metal–Insulator–Metal (MIM) Capacitors

by Li Xiong, Jin Hu, Zhao Yang, Xianglin Li, Hang Zhang and Guanhua Zhang

Molecules 2022, 27(12), 3951; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27123951 - 20 Jun 2022

Cited by 7 | Viewed by 3098

Abstract

This study presents the construction and dielectric properties investigation of atomic-layer-deposition Al₂O₃/TiO₂/HfO₂ dielectric-film-based metal–insulator–metal (MIM) capacitors. The influence of the dielectric layer material and thickness on the performance of MIM capacitors are also systematically investigated. The [...] Read more.

This study presents the construction and dielectric properties investigation of atomic-layer-deposition Al₂O₃/TiO₂/HfO₂ dielectric-film-based metal–insulator–metal (MIM) capacitors. The influence of the dielectric layer material and thickness on the performance of MIM capacitors are also systematically investigated. The morphology and surface roughness of dielectric films for different materials and thicknesses are analyzed via atomic force microscopy (AFM). Among them, the 25 nm Al₂O₃-based dielectric capacitor exhibits superior comprehensive electrical performance, including a high capacitance density of 7.89 fF·µm⁻², desirable breakdown voltage and leakage current of about 12 V and 1.4 × 10⁻¹⁰ A·cm⁻², and quadratic voltage coefficient of 303.6 ppm·V⁻². Simultaneously, the fabricated capacitor indicates desirable stability in terms of frequency and bias voltage (at 1 MHz), with the corresponding slight capacitance density variation of about 0.52 fF·µm⁻² and 0.25 fF·µm⁻². Furthermore, the mechanism of the variation in capacitance density and leakage current might be attributed to the Poole–Frenkel emission and charge-trapping effect of the high-k materials. All these results indicate potential applications in integrated passive devices. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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12 pages, 2342 KiB

Open AccessArticle

Binding and Degradation Reaction of Hydroxide Ions with Several Quaternary Ammonium Head Groups of Anion Exchange Membranes Investigated by the DFT Method

by Mirat Karibayev, Bauyrzhan Myrzakhmetov, Sandugash Kalybekkyzy, Yanwei Wang and Almagul Mentbayeva

Molecules 2022, 27(9), 2686; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27092686 - 21 Apr 2022

Cited by 11 | Viewed by 2249

Abstract

Commercialization of anion exchange membrane fuel cells (AEMFCs) has been limited due to the chemical degradation of various quaternary ammonium (QA) head groups, which affects the transportation of hydroxide (

{OH}^{-}

) ions in AEMs. Understanding how various QA head groups bind [...] Read more.

Commercialization of anion exchange membrane fuel cells (AEMFCs) has been limited due to the chemical degradation of various quaternary ammonium (QA) head groups, which affects the transportation of hydroxide (

{OH}^{-}

) ions in AEMs. Understanding how various QA head groups bind and interact with hydroxide ions at the molecular level is of fundamental importance to developing high-performance AEMs. In this work, the binding and degradation reaction of hydroxide ions with several QA head groups—(a) pyridinium, (b) 1,4-diazabicyclo [2.2.2] octane (DABCO), (c) benzyltrimethylammonium (BTMA), (d) n-methyl piperidinium, (e) guanidium, and (f) trimethylhexylammonium (TMHA)—are investigated using the density functional theory (DFT) method. Results of binding energies (“∆” EBinding) show the following order of the binding strength of hydroxide ions with the six QA head groups: (a) > (c) > (f) > (d) > (e) > (b), suggesting that the group (b) has a high transportation rate of hydroxide ions via QA head groups of the AEM. This trend is in good agreement with the trend of ion exchange capacity from experimental data. Further analysis of the absolute values of the LUMO energies for the six QA head groups suggests the following order for chemical stability: (a) < (b)~(c) < (d) < (e) < (f). Considering the comprehensive studies of the nucleophilic substitution (S_N2) degradation reactions for QA head groups (c) and (f), the chemical stability of QA (f) is found to be higher than that of QA (c), because the activation energy (“∆” EA) of QA (c) is lower than that of QA (f), while the reaction energies (“∆” ER) for QA (c) and QA (f) are similar at the different hydration levels (HLs). These results are also in line with the trends of LUMO energies and available chemical stability data found through experiments. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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Review

Jump to: Research

24 pages, 12420 KiB

Open AccessReview

The Development of iDPC-STEM and Its Application in Electron Beam Sensitive Materials

by Hongyi Wang, Linlin Liu, Jiaxing Wang, Chen Li, Jixiang Hou and Kun Zheng

Molecules 2022, 27(12), 3829; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules27123829 - 14 Jun 2022

Cited by 5 | Viewed by 4206

Abstract

The main aspects of material research: material synthesis, material structure, and material properties, are interrelated. Acquiring atomic structure information of electron beam sensitive materials by electron microscope, such as porous zeolites, organic-inorganic hybrid perovskites, metal-organic frameworks, is an important and challenging task. The [...] Read more.

The main aspects of material research: material synthesis, material structure, and material properties, are interrelated. Acquiring atomic structure information of electron beam sensitive materials by electron microscope, such as porous zeolites, organic-inorganic hybrid perovskites, metal-organic frameworks, is an important and challenging task. The difficulties in characterization of the structures will inevitably limit the optimization of their synthesis methods and further improve their performance. The emergence of integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM), a STEM characterization technique capable of obtaining images with high signal-to-noise ratio under lower doses, has made great breakthroughs in the atomic structure characterization of these materials. This article reviews the developments and applications of iDPC-STEM in electron beam sensitive materials, and provides an outlook on its capabilities and development. Full article

(This article belongs to the Special Issue Advanced Energy Storage Materials and Their Applications)

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