查找使用阿拉丁产品的科研文献

Fiber-in-tube and particle-in-tube hierarchical nanostructures enable high energy density of MnO2-based asymmetric supercapacitors

Guangdi Nie,Yaxue Luan,Zongkui Kou,Jiangmin Jiang,Zhenyuan Zhang,Na Yang,John Wang,Yun-Ze Long

Manganese dioxide (MnO 2 ) promises for high-performance asymmetric suprecapacitors, owing to its high theoretical capacity, abundant source, and low cost. However, insufficient practically-achievable capacity and relatively narrow voltage window in alkaline electrolyte are blocking high energy density of MnO 2 -based supercapacitors , where strategies for activating its capacitive performance and widening voltage window are the top priorities to solve the bottleneck problems. Herein, both the fiber-in-tube (NCCM-FiT) and particle-in-tube (NCCM-PiT) nanostructures coulping active NiCoO x nanoparticles and conductive carbon with MnO 2 tubes have been purposely fabricated, using the electrospun nickel cobalt oxides/carbon nanofibers (NCO/CNFs) as the self-template agents for enhanced energy density of MnO 2 -based supercapacitors. These hierarchical hollow nanotubes with gradient pores and unique compositions yield excellent capacitive properties, in terms of a competitive capacity (431.7 F g −1 or 431.7 C g −1 , 0.5 A g −1 ), which is 2.7 times that of the MnO 2 nanotubes-based electrodes. A maximum energy density of 46.4 Wh kg −1 is obtained at the power density of 400 W kg −1 for the asymmetric device assembled with the NCCM-PiT-based positive electrode and the electrospun CNFs-based negative electrode. The remarkable energy density demonstrated by these hierarchical hollow nanotubes exemplifies a novel and effective design in electrode materials for the asymmetric supercapacitors (ASCs) with superior performance.

MnO2/TiO2 Nanotube Array-Coated Titanium Substrates as Anodes for Electrocatalytic Oxidation of As(III) in Aqueous Solution

Yuanjie Xiong,Xiang Liu,Tian Cheng Zhang,Shaojun Yuan

The conversion of As(III) to As(V) in groundwater is an urgent issue, owing to the higher mobility, stronger toxicity, and weaker binding ability of As(III). In this work, the electrocatalytic oxidation of As(III) was efficiently achieved with a facile and environmentally benign method by using hierarchical MnO2-deposited TiO2 nanotube arrays (MnO2/TNAs) as the anode. The electrocatalytic oxidation performance of the as-fabricated MnO2/TNA-coated anode was systematically investigated. The results exhibited that such as-fabricated MnO2/TNAs had a high oxidation efficiency of 90% at a low concentration of As(III) (1 mg L–1). Furthermore, the reaction mechanism was systematically studied by electron spin resonance and free radical capture experiments. The oxidation of As(III) was accomplished via both direct oxidation on the anode surface and indirect oxidation of the reactive oxygen species. The highly efficient TNA-based anode offers a potentially promising advanced material for electrochemical oxidation of trace As(III) in the practical field.

The combination of MnO2@Lipo-coated gefitinib and bevacizumab inhibits the development of non-small cell lung cancer

Jisong Zhang,Li Xu,Huihui Hu,Enguo Chen

A Self-Assembly Fluorescence Sensing Platform for Glutathione Detection Based on Eco-Friendly Quantum Dots and MnO2 Nanosheets

Cai Qiyong,Zhang Lin,Geng Xin,Ge Jia,Li Zhaohui

Glutathione (GSH), a thiol-containing tripeptide, has a pivotal role in maintaining the normally physiological environment in biology. Here, we report a novel self-assembly fluorescence resonance energy transfer (FRET) sensing platform for GSH detection by using the environment-friendly Cu:Zn–In–S/ZnS quantum dots (QDs) and MnO2 nanosheets. In this assay, fluorescence of Cu:Zn– In–S/ZnS QDs could be quenched by MnO2 nanosheets based on FRET. Upon the addition of GSH, MnO2 nanosheets were reduced into Mn2+ ions because of the rapid redox reaction, and consequently the fluorescence of QDs was recovered. A good linear relationship was obtained from 1 to 20 μM for the detection of GSH with a low detection limit of 500 nM. Meanwhile, the sensing system also exhibited high selectivity against other electrolytes and biomolecules. Moreover, the satisfactory results in the determination of GSH in serum samples indicate that the assay holds great potential for detecting GSH in biological fluids. This method shows many advantages including high sensitivity, short assay time, good simplicity as well as label-free and environmental friendly, which is expected to facilitate the GSH quantification relating to biological and biomedical studies.

Construction of K and Tb Co-doped MnO2 nanoparticles for enhanced oxidation and detoxication of organic dye waste

Haiqing Wang,Zhenda Liang,Chao Liu,Lishan Zhu,Yongtao Xu,Li Zhou,Bing Yan

Developing low-cost and efficient materials for dye pollutant removal under mild condition remains a great challenge. Here K + and Tb 3+ co-doped porous MnO 2 (K–Tb–MnO 2 ) nanoparticles with tailored properties including crystal structure, surface area and catalytic activity have been synthesized. Experimental results reveal that K–Tb–MnO 2 nanoparticle has higher specific surface area, Mn 3+ content and surface oxygen vacancies than pristine MnO 2 nanoparticle and single-doped MnO 2 materials, showing the uniqueness of dual-doped metal ions . Using methyl blue (MB) as a model pollutant, its removal efficiency by K–Tb–MnO 2 nanoparticles within 5 min is 93.6%, which is 18, 8.3, and 2.9 times higher than that of MnO 2 , K–MnO 2 , and Tb–MnO 2 nanomaterials, respectively. Oxalic acid triggered MnO 2 material dissolving assay and FT-IR spectrum suggested that remarkable performance of K–Tb–MnO 2 nanoparticle toward MB removal can be attributed to a combined effect of adsorption (16% MB removal) and catalytic degradation (84% MB removal). Moreover, K–Tb–MnO 2 nanoparticle mediated MB degradation is demonstrated to be a combination of non-radical oxidation by Mn 3+ and radical-participated degradation, with 1 O 2 as the main species. And the intermediates and pathways of MB degradation were studied by liquid chromatography-mass spectrometry. Importantly, cell viability experiment suggests that the toxicity of MB dye could be efficiently alleviated after the treatment with K–Tb–MnO 2 nanoparticle. These results demonstrate the great potential of the novel K–Tb–MnO 2 particles to be used as a highly effective nanomaterials to reduce the risk of dye wastes toward the environment and human health.

Heterogeneous electro-Fenton catalysis with self-supporting CFP@MnO2-Fe3O4/C cathode for shale gas fracturing flowback wastewater

Pei Dong,Xi Chen,Meiting Guo,Zhiyuan Wu,Haolong Wang,Feifei Lin,Jinqiang Zhang,Shuaijun Wang,Chaocheng Zhao,Hongqi Sun

Self-supporting electrodes have triggered great interests in improving electro-Fenton (EF) system for degradation of refractory organic pollutants . In this work, a novel self-supporting carbon fiber paper (CFP) electrode modified by transition metals, e.g. Fe and Mn, was fabricated and employed as a heterogeneous EF cathode. The prepared electrode exhibited excellent degradation for a number of typical organic pollutants along with superior stability. Remarkably, a high removal efficiency was achieved in the EF treatment of shale gas fracturing flowback wastewater. Results indicated that 65.2% TOC and 74.8% COD were eliminated after 4 h degradation. The residual COD value of the real wastewater was 80 mg L −1 , meeting the emission requirement of the integrated wastewater discharge standard (COD   ＜   100 mg L −1 ) with a low specific energy consumption of 6.9   kWh   kg −1   COD −1 . This work demonstrates a competing alternative for efficient decontamination of real wastewater using an electro-Fenton strategy with a low-cost electrode.

Fast Photothermal Regulation of All-in-One Electrochromic Dynamic Windows Based on Synergetic Electrodeposition of CuBi and MnO2

Ying Lv,Xiaoting Li,Xiaodan Guo,Zhiqiang Liu,Sensen Jia,Ying Du,Jinhui Wang,Liang Liu,Guofa Cai

Electrochromic dynamic windows represent an attractive avenue for enhancing the energy-saving efficiency of buildings. However, the practical application of dynamic windows remains in its infancy due to challenges related to efficient optical modulation and cost-effective manufacturing. Herein, we report an all-in-one electrochromic dynamic window through synergetic electrodeposition of CuBi and MnO 2 , featuring a simplified three-layer configuration. The synergy of dual electrodeposition, coupled with Br − /Br 3 − redox pair, endows the CuBi//MnO 2 system with reversible color transitions between transparent and brown-black states. Benefiting from a well-balanced charge distribution, the CuBi//MnO 2 system demonstrates superior photothermal regulation in the visible-near-infrared region, including large optical modulation of 90.6% at 500 nm and 58% at 1100 nm, short response time of 16.1/12.9 s at 500 nm and 21.4/8.1 s at 1100 nm in coloration/bleaching processes. Outdoor test indicates that the assembled large-size dynamic window can lower the temperature by 5 to 10°C within a homemade house. Further simulation suggests that implementing the dynamic window can reduce annual energy consumption in buildings by up to 95.7 MJ/m 2 and decrease average CO 2 emissions by 18.8 kg/m 2 in subtropical regions of China. Our work offers a straightforward and effective strategy for developing low-cost energy-saving dynamic window technologies.

Lipase-Activated MnO2 Nanoflowers for Precise Biofilm Imaging and Oxygen-Enhanced Sonodynamic Therapy to Promote Diabetic Wound Healing

Dongqiu Li,Bingyi Xu,Feifei Ren,Jiajing Yu,Yan Tong,Shiwu Deng,Hezhong Jiang

Diabetic wound healing is substantially impaired by biofilm infections, oxidative stress, and persistent hypoxia, which present major challenges for timely diagnosis and treatment. In this study, theranostic nanoparticles (NPs) were engineered to facilitate lipase-triggered biofilm theranostics and accelerate wound healing. Theranostic Mn-TC NPs were prepared by grafting a fluorescent sonosensitizer, meso-tetra (4-carboxyphenyl) porphine (TCPP), onto manganese dioxide (MnO 2 ) nanoflowers, quenching the fluorescence emissions of TCPP. Upon encountering biofilms in vivo, the elevated lipase hydrolyzes ester linkages within the Mn-TC NPs, liberating TCPP to restore its fluorescence emission and enabling the real-time visualization of biofilm-infected wounds. MnO 2 nanoflowers offer abundant reaction sites for TCPP grafting while enhancing the catalysis of hydrogen peroxide to generate oxygen. The boosted oxygen evolution promoted the sonodynamic therapy effect of ultrasound-activated TCPP, achieving 94.0% reduction in biofilm biomass and 99.9% bacterial clearance. Engineering NPs accelerate wound healing by simultaneously eradicating biofilms, modulating inflammatory states, enhancing collagen deposition, and promoting angiogenesis. This study presents a novel theranostic strategy for biofilm-triggered visual imaging and an antibiotic-free therapy for diabetic wounds.

Lotus leaf-inspired MCMB/MnO2 superhydrophobic composite coating simultaneously boosts thermal dissipation and electromagnetic shielding for aerospace avionics

Jiahuan Wang,Zuozhu Yin,Xiangyu Han,Yongcun Ma,Zhen Hong,Chan Xie,Zhiyang Jiang,Yidan Luo

Avionics equipment often use epoxy resin as encapsulation material. However, epoxy resins have limited performance in terms of heat dissipation, electromagnetic shielding, and resistance to moisture and heat. As the integration of avionics continues to increase, epoxy resins have become more and more difficult to meet the stringent requirements for high reliability of avionics in the aerospace industry. In this study, inspired by the unique structure of lotus leaves, a thin film composite of mesophase carbon microspheres (MCMB) and manganese dioxide (MnO 2 ) was prepared on the surface of a copper foil using a mechanical hybrid spraying method. The film exhibits excellent superhydrophobicity with a water contact angle of 161.1°. This performance was attributed to its micro- and nanoscale roughness structure and low surface energy modification by POTS/stearic acid. In terms of infrared stealth, the composite material effectively suppresses thermal radiation through a trapped air layer and gradient thermal resistance design. In addition, the material’s electromagnetic shielding effectiveness in the 2.4 GHz band reaches −56 dB, originating from the synergistic effect of reflection loss in the copper substrate and dielectric absorption in MnO 2 . At the same time, the three-dimensional network constructed by the MCMBs gives the material high thermal conductivity, which significantly improves the thermal management efficiency. The composite film also has good abrasion resistance, chemical stability and self-cleaning function, which is suitable for avionics and other fields of protection, providing a new solution to solve the problem of avionics packaging.

Regulating electronic state of δ-MnO2 through an organic-inorganic hybrid engineering for boosted low-temperature NOx elimination

Hanbo Shi,Nannan Zhang,Wei Guo,Tancheng Dong,Bihui Zhou,Lanlan Yu,Baojun Liu,Jincheng Mu

Birnessite-type δ-MnO 2 is a promising candidate for low-temperature NH 3 -SCR reaction owning to its excellent redox properties. However, its performance is severely hampered by the excessive oxidation state of Mn species, which induces strong NH 3 chemisorption and subsequent over-oxidation to NO x . Herein, phenylalanine-functionalized δ-MnO 2 nanosheets (MnO x -Phe) were developed, leveraging Phe's coordinating –NH 2 group to modulate surface properties of Mn species. The optimal MnO x -Phe-0.1 catalyst achieves ∼90% NO x conversion at 75 °C with a broad temperature window from 75 to 210 °C (GHSV = 50,000 h −1 ), representing a reaction rate 4.8 to 8.2 times greater than that of pure δ-MnO 2 . Additionally, the catalyst exhibits remarkable resistance against SO 2 and H 2 O. Comprehensive characterizations and density functional theory calculations reveal that Phe modification shifts down the d -band center of δ-MnO 2 from −1.22 eV to −2.78 eV, and attenuates the oxidation state of Mn species. This unique configuration suppresses the over-oxidation of NH 3 and weakens the interaction between catalyst and poisons, while promoting the activation of NH 3 to *NH 2 with a lower energy barrier, thus driving a desired Eley-Rideal pathway and endowing strong tolerance against SO 2 and H 2 O at low temperatures. This work provides a novel organic-inorganic hybrid strategy for designing robust low-temperature NH 3 -SCR catalysts with superior activity and poison resistance.

Graphene-Composite δ-MnO2 Nanoflower Cathode Enhances Zinc Storage Performance and Cycling Stability in Aqueous Zinc Ion Batteries

You Li,Jinjian Lv,Yuning Sun,Lulu Zhan,Weiming Chen

MnO 2 is the most promising cathode material for aqueous zinc ion batteries (AZIBs), but poor conductivity, structural instability, and slow Zn 2+ kinetics in MnO 2 -based AZIBs still limit their practical use. Here, we present the introduction of graphene (Gr) into δ-MnO 2 with a layered structure designed for AZIBs to understand the effect of carbon materials on the electrochemical behavior of δ-MnO 2 cathodes. Nanoflower-structured δ-MnO 2 composites with graphene were fabricated via a one-step hydrothermal synthesis method. Owing to the incorporation of Gr, the cycling stability, rate performance, and reversibility of δ-MnO 2 have been significantly enhanced. The results show that at a current density of 0.5 A g − 1 , the δ-MnO 2 -1.5 h/Gr electrode exhibits a specific capacity of 125 mAh g − 1 with a capacity retention of 53.4% and a high Coulombic efficiency of 99.2%. At a higher current density of 1 A g − 1 , this electrode delivers a specific capacity of 142.5 mAh g − 1 after 1000 cycles, substantially higher than that of the δ-MnO 2 -1.5 h electrode. In addition, electrochemical data show that δ-MnO 2 -1.5 h/Gr possesses a higher pseudo-capacitance percentage and best rate performance. This study confirms that incorporating carbon materials is an effective strategy for enhancing the energy storage performance of δ-MnO 2 in AZIBs and understanding its charge-discharge mechanism. Graphical The incorporation of graphene (Gr) improved the cycling stability, rate capability, and reversibility of δ-MnO2. δ-MnO2/Gr possessed higher ion diffusion rates and higher pseudo-capacitance occupancy, and exhibited the best rate performance. Thus, improving the zinc storage performance and cycling stability of zinc ion water batteries.

A Novel Cr2O3/MnO2-x Electrode for Lithium-Oxygen Batteries with Low Charge Voltage and High Energy Efficiency

Zhaohuan Wei,Zhiyuan Zhang,Yaqi Ren,Hong Zhao

A high energy efficiency, low charging voltage cathode is of great significance for the development of non-aqueous lithium-oxygen batteries. Non-stoichiometric manganese dioxide (MnO2-x) and chromium trioxide (Cr2O3) are known to have good catalytic activities for the discharging and charging processes, respectively. In this work, we prepared a cathode based on Cr2O3 decorated MnO2-x nanosheets via a simple anodic electrodeposition-electrostatic adsorption-calcination process. This combined fabrication process allowed the simultaneous introduction of abundant oxygen vacancies and trivalent manganese into the MnO2-x nanosheets, with a uniform load of a small amount of Cr2O3 on the surface of the MnO2-x nanosheets. Therefore, the Cr2O3/MnO2-x electrode exhibited a high catalytic effect for both discharging and charging, while providing high energy efficiency and low charge voltage. Experimental results show that the as-prepared Cr2O3/MnO2-x cathode could provide a specific capacity of 6,779 mA·h·g−1 with a terminal charge voltage of 3.84 V, and energy efficiency of 78%, at a current density of 200 mA·g−1. The Cr2O3/MnO2-x electrode also showed good rate capability and cycle stability. All the results suggest that the as-prepared Cr2O3/MnO2-x nanosheet electrode has great prospects in non-aqueous lithium-oxygen batteries.