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Yang Liu

Bio: Yang Liu is an academic researcher from Dalian University of Technology. The author has contributed to research in topics: Catalysis & Chemical vapor deposition. The author has an hindex of 20, co-authored 89 publications receiving 1239 citations. Previous affiliations of Yang Liu include University of Jinan & Tsinghua University.


Papers
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TL;DR: In this paper, hollow polyhedral hybrid CoSe2 nanospheres are synthesized from CNT-bridged carbon-coated CoSe 2 nanosphere polyhedral hybrids (CoSe2@C/CNTs), which are used as anode materials for SIBs.
Abstract: Nanostructured CoSe2 anode materials hold great promise for sodium ion batteries (SIBs), drawing much recent research attention However, high-performance CoSe2 based anodes are still challenging to obtain Herein, using zeolitic imidazolate framework-67 (ZIF-67) particles as the starting material, nondestructive hollow polyhedral hybrids have been synthesized successfully, which are structured from CNT-bridged carbon-coated CoSe2 nanospheres (CoSe2@C/CNTs) During the synthesis, the controlled in situ growth of CNTs introduces additional mesopores and open channels to the hybrids, and avoids serious agglomeration of the CoSe2 nanospheres When employed as anode materials for SIBs with ether-based electrolyte, the CoSe2@C/CNTs show overwhelming merits over graphitic carbon-coated CoSe2 nanosphere polyhedral hybrids (CoSe2@GC) and bare CoSe2 particles Specifically, the CoSe2@C/CNTs anode displays a high reversible capacity (∼470 mA h g−1 at 02 A g−1), a good rate capability of ∼373 mA h g−1 even at 10 A g−1, and an excellent cycling stability of over 1000 cycles with a capacity retention of ∼100% calculated from the 70th cycle In addition, the electrochemical reaction dynamics analysis indicates a considerable capacitive contribution during the discharge–charge cycles, which is beneficial to enhance the rate capability and cyclability of the CoSe2@C/CNTs anode Such results could be ascribed to the stable ether-based electrolyte-active material intermediates, improved electrolyte-active material contact, and shortened charge transfer paths afforded by the unique hybrid nanostructure

212 citations

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TL;DR: In this paper, the best catalyst (H-MnO2 (30-0.2-6)) could be tailored via a facile and green process by engineering a proper combination of treatment temperature (30 ǫ°C), HNO3 aqueous concentration ( 0.2 ÃǫM) and treatment period (6 Ã h). And the thus-obtained MnO2 exhibited a stable removal efficiency of ˜94% for 318 Ã pm of benzene under a high space velocity of 120 Ã l·g−
Abstract: Volatile organic compounds (VOCs) are notorious for global air pollution. It is key to find a material with high and stable activity to catalytically oxidize VOCs at low temperatures. In this paper, benzene, as a typical VOC contaminant, could be completely oxidized on a highly efficient and moisture-resistant birnessite MnO2 at temperatures significantly lower than the reported values in literature. The best catalyst (H-MnO2 (30-0.2-6)) could be tailored via a facile and green process by engineering a proper combination of treatment temperature (30 °C), HNO3 aqueous concentration (0.2 M) and treatment period (6 h). The thus-obtained MnO2 exhibited a stable removal efficiency of ˜94% for 318 ppm of benzene under a high space velocity of 120 L·g−1 h−1 and 1.5 vol.% H2O at 250 °C. XRD, SEM, (HR)TEM, EDS mapping, XPS, H2-TPR, O2-TPD and pyridine adsorption IR were combined with the deliberately designed C6H6-TPD, surface oxidation reaction of benzene and CO2-TPD to disclose the tremendous role of acid treatment in benzene oxidation. The increased acid sites and acidity of the acid-treated surface promoted the adsorption and activation of gaseous benzene, and the lattice oxygen and surface adsorbed oxygen became more facile and reactive due to the generated active oxygen vacancies via acid treatment, these two favorable factors together with the easy desorption of reaction products resulting in the excellent performance of the acid-treated sample. Finally, the acid treatment method can be extended to most of other crystal structures of manganese dioxides except α-MnO2.

133 citations

Journal ArticleDOI
TL;DR: Insight is provided into a new pathway for the creation of free-standing composite electrodes used in the energy storage and conversion of sodium ion batteries through in situ reduction, evaporation-induced self-assembly, and sulfuration.
Abstract: Ultrafine SnS2 nanocrystals–reduced graphene oxide nanoribbon paper (SnS2–RGONRP) has been created by a well-designed process including in situ reduction, evaporation-induced self-assembly, and sulfuration. The as-formed SnS2 nanocrystals possess an average diameter of 2.3 nm and disperse on the surface of RGONRs uniformly. The strong capillary force formed during evaporation leads to a compact assembly of RGONRs to give a flexible paper structure with a high density of 0.94 g cm–3. The as-prepared SnS2–RGONRP composite could be directly used as free-standing electrode for sodium ion batteries. Due to the synergistic effects between the ultrafine SnS2 nanocrystals and the conductive, tightly connected RGONR networks, the composite paper electrode exhibits excellent electrochemical performance. A high volumetric capacity of 508–244 mAh cm–3 was obtained at current densities in the range of 0.1–10 A g–1. Discharge capacities of 334 and 255 mAh cm–3 were still kept, even after 1500 cycles tested at current d...

99 citations

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TL;DR: In this article, highly water-resistant birnessite-type MnO2 was designed for humid ozone (O3) decomposition, which is important for alleviating global O3 pollution.

91 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of tungsten doping on the activity of α-MnO2 for ozone decomposition was investigated, and the results indicated that doping of Tungsten made the morphology change from nanorods to nanoparticles with great increase of specific surface area.
Abstract: Ozone is a universal air pollutant and its stable decomposition under humid condition is still a challenge. In this work, the effect of tungsten doping on the activity of α-MnO2 for ozone decomposition was first investigated. Tungsten was doped into MnO2 with addition of tungstate in a hydrothermal reaction solution. The as-synthesized catalysts were characterized by XRD, SEM, TEM, BET, XPS, ICP-AES, Raman, H2-TPR, O2-TPD, NH3-TPD and EPR. The results indicated that doping of tungsten made the morphology change from nanorods to nanoparticles with great increase of specific surface area. In addition, more oxygen vacancies were formed, and the surface acidity was greatly enhanced, accordingly the tungsten-doped MnO2 exhibited enhanced activity and stability at room temperature under dry and particularly under humid condition (RH = 65%). It indicates that the doping with a high valence metal such as W6+ into MnO2 is a promising method to obtain efficient ozone-decomposition catalyst.

75 citations


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TL;DR: The role of defects and impurities on the transport and optical properties of bulk, epitaxial, and nanostructures material, the difficulty in p-type doping, and the development of processing techniques like etching, contact formation, dielectrics for gate formation, and passivation are discussed in this article.
Abstract: Gallium oxide (Ga2O3) is emerging as a viable candidate for certain classes of power electronics, solar blind UV photodetectors, solar cells, and sensors with capabilities beyond existing technologies due to its large bandgap. It is usually reported that there are five different polymorphs of Ga2O3, namely, the monoclinic (β-Ga2O3), rhombohedral (α), defective spinel (γ), cubic (δ), or orthorhombic (e) structures. Of these, the β-polymorph is the stable form under normal conditions and has been the most widely studied and utilized. Since melt growth techniques can be used to grow bulk crystals of β-GaO3, the cost of producing larger area, uniform substrates is potentially lower compared to the vapor growth techniques used to manufacture bulk crystals of GaN and SiC. The performance of technologically important high voltage rectifiers and enhancement-mode Metal-Oxide Field Effect Transistors benefit from the larger critical electric field of β-Ga2O3 relative to either SiC or GaN. However, the absence of clear demonstrations of p-type doping in Ga2O3, which may be a fundamental issue resulting from the band structure, makes it very difficult to simultaneously achieve low turn-on voltages and ultra-high breakdown. The purpose of this review is to summarize recent advances in the growth, processing, and device performance of the most widely studied polymorph, β-Ga2O3. The role of defects and impurities on the transport and optical properties of bulk, epitaxial, and nanostructures material, the difficulty in p-type doping, and the development of processing techniques like etching, contact formation, dielectrics for gate formation, and passivation are discussed. Areas where continued development is needed to fully exploit the properties of Ga2O3 are identified.

1,535 citations

Journal ArticleDOI
TL;DR: This dendrite issue in Zn anodes, with regard to fundamentals, protection strategies, characterization techniques, and theoretical simulations, is systematically discussed and comprehensively summarized to generate an overview of respective superiorities and limitations of various strategies.
Abstract: Aqueous Zn batteries that provide a synergistic integration of absolute safety and high energy density have been considered as highly promising energy-storage systems for powering electronics. Despite the rapid progress made in developing high-performance cathodes and electrolytes, the underestimated but non-negligible dendrites of Zn anode have been observed to shorten battery lifespan. Herein, this dendrite issue in Zn anodes, with regard to fundamentals, protection strategies, characterization techniques, and theoretical simulations, is systematically discussed. An overall comparison between the Zn dendrite and its Li and Al counterparts, to highlight their differences in both origin and topology, is given. Subsequently, in-depth clarifications of the specific influence factors of Zn dendrites, including the accumulation effect and the cathode loading mass (a distinct factor for laboratory studies and practical applications) are presented. Recent advances in Zn dendrite protection are then comprehensively summarized and categorized to generate an overview of respective superiorities and limitations of various strategies. Accordingly, theoretical computations and advanced characterization approaches are introduced as mechanism guidelines and measurement criteria for dendrite suppression, respectively. The concluding section emphasizes future challenges in addressing the Zn dendrite issue and potential approaches to further promoting the lifespan of Zn batteries.

452 citations

Journal Article
TL;DR: In this paper, the authors demonstrate a novel technology for constructing large-scale electronic systems based on graphene/molybdenum disulfide (MoS2) heterostructures grown by chemical vapor deposition.
Abstract: Two-dimensional (2D) materials have generated great interest in the past few years as a new toolbox for electronics. This family of materials includes, among others, metallic graphene, semiconducting transition metal dichalcogenides (such as MoS2), and insulating boron nitride. These materials and their heterostructures offer excellent mechanical flexibility, optical transparency, and favorable transport properties for realizing electronic, sensing, and optical systems on arbitrary surfaces. In this paper, we demonstrate a novel technology for constructing large-scale electronic systems based on graphene/molybdenum disulfide (MoS2) heterostructures grown by chemical vapor deposition. We have fabricated high-performance devices and circuits based on this heterostructure, where MoS2 is used as the transistor channel and graphene as contact electrodes and circuit interconnects. We provide a systematic comparison of the graphene/MoS2 heterojunction contact to more traditional MoS2-metal junctions, as well as a theoretical investigation, using density functional theory, of the origin of the Schottky barrier height. The tunability of the graphene work function with electrostatic doping significantly improves the ohmic contact to MoS2. These high-performance large-scale devices and circuits based on this 2D heterostructure pave the way for practical flexible transparent electronics.

439 citations

Journal ArticleDOI
TL;DR: Morphological analysis reveals that vertically aligned Zn dendrites with sharp tips gradually become passivated and finally generate a smooth surface, and a first-in-class electrohealing methodology is developed to eliminate already-formed dendrite, generating extremely prolonged lifespans.
Abstract: The dendritic issue in aqueous zinc-ion batteries (ZBs) using neutral/mild electrolytes has remained an intensive controversy for a long time: some researchers assert that dendrites severely exist while others claim great cycling stability without any protection. This issue is clarified by investigating charge/discharge-condition-dependent formation of Zn dendrites. Lifespan degradation (120 to 1.2 h) and voltage hysteresis deterioration (134 to 380 mV) are observed with increased current densities due to the formation of Zn dendrites (edge size: 0.69-4.37 µm). In addition, the capacity is also found to remarkably affect the appearance of the dendrites as well. Therefore, at small current densities or loading mass, Zn dendrites might not be an issue, while the large conditions may rapidly ruin batteries. Based on this discovery, a first-in-class electrohealing methodology is developed to eliminate already-formed dendrites, generating extremely prolonged lifespans by 410% at 7.5 mA cm-2 and 516% at 10 mA cm-2 . Morphological analysis reveals that vertically aligned Zn dendrites with sharp tips gradually become passivated and finally generate a smooth surface. This developed electrohealing strategy may promote research on metal dendrites in various batteries evolving from passive prevention to active elimination, rescuing in-service batteries in situ to achieve elongated lifetime.

432 citations

Journal ArticleDOI
TL;DR: The identity, body of knowledge, safety concerns and antimicrobial resistance of valid taxonomic units were assessed and Lactobacillus animalis was a new taxonomic unit recommended to have the QPS status.
Abstract: Qualified presumption of safety (QPS) was developed to provide a generic safety evaluation for biological agents to support EFSA's Scientific Panels. The taxonomic identity, body of knowledge, safety concerns and antimicrobial resistance are assessed. Safety concerns identified for a taxonomic unit (TU) are where possible to be confirmed at strain or product level, reflected by 'qualifications'. No new information was found that would change the previously recommended QPS TUs and their qualifications. The list of microorganisms notified to EFSA was updated with 54 biological agents, received between April and September 2019; 23 already had QPS status, 14 were excluded from the QPS exercise (7 filamentous fungi, 6 Escherichia coli, Sphingomonas paucimobilis which was already evaluated). Seventeen, corresponding to 16 TUs, were evaluated for possible QPS status, fourteen of these for the first time, and Protaminobacter rubrum, evaluated previously, was excluded because it is not a valid species. Eight TUs are recommended for QPS status. Lactobacillus parafarraginis and Zygosaccharomyces rouxii are recommended to be included in the QPS list. Parageobacillus thermoglucosidasius and Paenibacillus illinoisensis can be recommended for the QPS list with the qualification 'for production purposes only' and absence of toxigenic potential. Bacillus velezensis can be recommended for the QPS list with the qualification 'absence of toxigenic potential and the absence of aminoglycoside production ability'. Cupriavidus necator, Aurantiochytrium limacinum and Tetraselmis chuii can be recommended for the QPS list with the qualification 'production purposes only'. Pantoea ananatis is not recommended for the QPS list due to lack of body of knowledge in relation to its pathogenicity potential for plants. Corynebacterium stationis, Hamamotoa singularis, Rhodococcus aetherivorans and Rhodococcus ruber cannot be recommended for the QPS list due to lack of body of knowledge. Kodamaea ohmeri cannot be recommended for the QPS list due to safety concerns.

347 citations