JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 31
·期 15
·12325-12332
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IF 2.22
Yang Yan,Li Jie,Zhang Huaiwu,Wang Gang,Gan Gongwen,Rao Yiheng
The development of miniaturized high frequency ferrite ceramics is attracting widely interest for next generation MLCI (multi-layer chip inductors). However, there exist short comings in the microstructure adversely affecting magnetic properties. In this study, 0.5 wt% MnO 2 - x wt% Bi 2 O 3 ( x = 0.1, 0.5, 1.0, 1.5, 2.0, and 3.0) were introduced into NiCuZn ferrites to adjust the microstructure at low temperatures. Also, the microstructure changes and high frequency magnetic properties of NiCuZn ferrites were investigated via controlling the addition of MnO 2 –Bi 2 O 3 and sintering temperatures. SEM results indicated that quantitative MnO 2 can suppress abnormal grain growth when optimized amount of Bi 2 O 3 was added. In addition, various amounts of Bi 2 O 3 were added to adjust the magnetic properties by controlling grain growth. Results revealed that 0.5 wt% MnO 2 -1.5 wt% Bi 2 O 3 composite addition is a critical point to enhance the homogeneity of the samples. Also, interestingly, the dominant contribution to dynamic magnetization mechanism changes from spin rotation to domain wall motion when the content of Bi 2 O 3 is greater than 1.0 wt%. Finally, fine microstructure of NiCuZn ferrites with high permeability ( μ ′ ≈ 291), high saturation magnetization ( M s ≈ 58.83 emu/g), high saturation flux density ( B s ≈ 290.04), high Q factor (~ 75) and enhanced cutoff frequency (~ 60 MHz) can be obtained sintered at 925 °C. Thus, this work may provide new guidance for developing RF frequency LTCC NiCuZn ferrite ceramics.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2018
·Vol. 20
·期 45
·28644-28648
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IF 3.906
Mengxin Zhao,Yang Tao,Wei Huang,Yi He
Although the enzyme-like activities of MnO2 nanosheets have been investigated, effective strategies for modulating their activities are still lacking. Herein, inspired by the pH-dependent activity of natural enzymes, we demonstrate that the oxidase-like activities of the MnO2 nanosheets are pH switchable and reversible. The MnO2 nanosheets show oxidase-like activities in an acidic medium, which can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to form blue oxidized TMB (oxTMB), while the corresponding activities are greatly weakened under alkaline conditions. The reaction mechanism is attributed to the fact that the MnO2 nanosheets can be transformed into hexagonal Na4MnO4 with a low reaction activity in an alkaline environment. Using the pH switchable oxidase-like activities of the MnO2 nanosheets and other reaction processes, we construct a visual three-input molecular majority logic gate with a single-vote veto function. In addition, an OR-INH cascade logic circuit is successfully realized as well.
研究领域:
生物化学
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纳米生物学
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分析化学
✓ 已验证
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Xingjie Lu,Zhen Liu,Xin Wang,Yuekun Liu,Hongchao Ma,Meiwen Cao,Wentao Wang,Taihong Yan
Novel MnO 2 @ZIF-8 nanocomposites were synthesized for efficient adsorptive removal of Sr 2+ from aqueous solution. ZIF-8 nanoparticles with controlled morphology and size were first synthesized by using amino acids to modulate the crystal nucleation and growth. Then, a layer of MnO 2 nanoparticles were deposited on ZIF-8 surface by using the adsorbed amino acid molecules as binding sites to mediate MnO 2 mineralization and by adjusting the reactive KMnO 4 concentration to control the size and surface density of the MnO 2 nanoparticles . The as-prepared MnO 2 @ZIF-8 nanocomposites showed a core-shell structure and displayed superior performance in Sr 2+ adsorption and removal from aqueous solution. The adsorption process can be described well by the pseudo-second-order equation. The adsorption isotherm accords well with the Langmuir model and the maximum adsorption capacity can reach 65.7 mg/g. The study paves a new way to develop novel inorganic nanocomposites as highly efficient and potential adsorbents for the treatment of radionuclide-containing wastewater.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 30
·18092-18099
·
IF 10.733
Zheng Zhang,Peng Mu,Jingxin Han,Jingxian He,Zhaoqi Zhu,Hanxue Sun,Weidong Liang,An Li
Solar vapor generation based on light-to-heat conversion via photothermal materials has been considered as one of the emerging technologies for utilizing solar energy. Here, we report the fabrication of a novel monolithic aerogel (PNGA) composed of hydrophilic treated MnO2 nanowires and reduced graphene oxide (rGO) followed by in situ coating of polypyrrole on the surface of the PNGA to construct a light-to-heat conversion layer for efficient solar steam generation. Analysis of the morphology and porosity of the PNGA shows that the aerogel is full of interconnected pores and open channels with a low apparent density (0.127 g cm−3) and large specific surface area (1142.7 m2 g−1), which endow it with excellent thermal insulation (a low thermal conductivity of 0.21882 W m−1 K−1 in the wet state), self-floating and rapid water transmission properties. Benefiting from the polypyrrole coating, the PNGA shows a superintense optical absorption of ca. 100%. Interestingly, a superhydrophilic wettability could be achieved after surface modification of the PNGA with phytic acid, which could dramatically enhance its water transportation ability. Furthermore, the PNGA maintains a certain mechanical strength (0.08 MPa under 30% strain), thus making it mechanically robust to withstand the harsh environment. Taking the advantages mentioned above, our PNGA possesses an outstanding energy conversion efficiency of 93.8% under 1 kW m–2 irradiation, which is 4.9 times that of pure water (19.1%). In addition to the excellent ionic isolation and dye liquid treatment ability, the PNGA shows excellent stability and its energy conversion efficiency remains nearly unchanged after ten consecutive tests. Based on its excellent mechanical stability and high recyclability and a simple and scalable manufacture process, our PNGA sample may have great potential as an efficient photothermal material for a wide range of large-scale applications such as solar steam generation, wastewater treatment, seawater desalination and so on.
研究领域:
材料科学
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能源技术
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产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2015
·
IF 4.772
Feili Lai,Yue-E Miao,Yunpeng Huang,Tai-Shung Chung,Tianxi Liu
Construction of MnO2-based hybrid nanostructures with carbonaceous materials has been considered as one of the most efficient strategies to overcome excessive aggregations of MnO2 particles. Here, a facile approach of growing δ-phase and γ-phase MnO2 with distinctly different morphologies on highly conductive NiCo2O4-doped carbon nanofibers (NCCNFs) through the combination of electrospinning, solution codeposition, and redox deposition methods is presented to form NCCNF@MnO2 nanosheet (or nanorod) core–sheath nanostructures. The obtained two kinds of flexible hybrid membranes with hierarchical nanostructures are both evaluated as electrodes for high-performance supercapacitors. The greatly improved specific surface areas for ionic adsorption, significantly enhanced conductivity of NCCNF, and an open three-dimensional network for rapid electron transportation during the electrochemical processes jointly lead to remarkably enhanced specific capacitances of 918 and 827 F g–1 (based on the active materials) at a scan rate of 2 mV s–1 and good cycling ability with 83.3% and 87.6% retention after 2000 cycles for NCCNF@MnO2 nanosheet and NCCNF@MnO2 nanorod hybrid membranes, respectively. Therefore, this work suggests a novel strategy for design and potential application of MnO2 hybrid materials in high-performance supercapacitors.
研究领域:
材料科学
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能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
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2018
·
IF 4.514
Jiajia Liu,Wei Wang,Richard K.K. Yuen,Zhou Gui,Yuan Hu
SnO 2 nanowires decorated MnO 2 nanosheets hybrids, were prepared and incorporated into epoxy resins to improve the flame retardancy and inhibite the smoke in combustion. SnO 2 -MnO 2 hybrids shows significant improve in flame retardancy, fire toxicity and thermal properties of epoxy nanocomposites, compared to neat epoxy and nanocomposites with a single SnO 2 or MnO 2 . The char residues and glass transition temperature of the epoxy/2 wt% SnO 2 -MnO 2 nanocomposite were remarkably increased. The peak heat release rate of EP/2 wt% SnO 2 -MnO 2 was significantly decreased by 62.9% than that of pure epoxy. TG-FTIR results that the concentration of organic volatiles of epoxy was significantly reduced and the toxic CO was suppressed after incorporating SnO 2 -MnO 2 . The physical barrier for SnO 2 -MnO 2 hybrids and the synergism between the catalysis effect of SnO 2 and MnO 2 can improve the flame retardancy of epoxy resin.
研究领域:
材料科学
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燃烧学
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纳米技术
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DOI
高影响因子
MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 4
·1-10
·
IF 5.3
Chen Yiting,Gong Chunhui,Chen Kaiwei,Wang Ziwei,He Manli,Wang Peng,Chen Kai,Jiao Yan,Yang Yi
Strontium-90 ( 90 Sr) is a major radioactive component that has attracted great attention, but its detection remains challenging since there are no specific energy rays indicative of its presence. Herein, a biosensor that is capable of rapidly detecting Sr 2+ ions is demonstrated. Simple colorimetric method for sensitive detection of Sr 2+ with the help of single-stranded DNA was developed by preparing MnO 2 nanorods as oxidase mimic catalysis 3,3′,5,5′-tetramethylbenzidine (TMB). Under weakly acidic conditions, MnO 2 exhibited a strong oxidase-mimicking activity to oxidize colorless TMB into blue oxidation products (oxTMB) with discernible absorbance signals. Nevertheless, the introduction of a guanine-rich DNA aptamer inhibited MnO 2 -mediated TMB oxidation and reduced oxTMB formation, resulting in blue fading and diminished absorbance. Upon the addition of strontium ions to the system, the aptamers formed a stable G-quadruplex structure with strontium ions, thereby restoring the oxidase-mimicking activity of MnO 2 . Under the best experimental conditions, the absorbance exhibits a linear relationship with the Sr 2+ concentration within the range 0.01–200 μM, with a limit of detection of 0.0028 µM. When the concentration of Sr 2+ from 10 −8 to 10 −6 mol L −1 , a distinct color change gradient could be observed in paper-based sensor. We successfully applied this approach to determine Sr 2+ in natural water samples, obtaining recoveries ranging from 97.6 to 103% with a relative standard deviation of less than 5%. By providing technical solutions for detection, our work contributed to the effective monitoring of transportation of radioactive Sr in the environment. Graphical abstract
研究领域:
生物化学
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环境科学
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Bioresources and Bioproducts
·
2020
·
IF 0
Dubin Dong
MnO 2 @MoS 2 /Polypyrrole ternary composite is prepared through hydrothermal methods and a simple oxidation process by using MnO 2 @MoS 2 sheet as the substrate and polypyrrole. The ternary composite serves as an electrode for pseudocapacitor which has more superior electrochemical properties compared with the binary complex. The supercapacitor electrode consists of two dimensional MoS 2 layers as load skeleton, MnO 2 providing electrochemical performance and polypyrrole improving high electric conductivity. These three components form a compact structure and synergistic effect leads to enhancing sufficient oxidation reduction for supercapacitor performance. Hence, MnO 2 @MoS 2 / Polypyrrole structure possesses higher specific capacitance of 490 F/g at a current density of 1 A/g and excellent cycling stability of 90% after 1000 cycles at 1 A/g. Here, Polypyrrole is also used as the bender material, exhibiting mechanical flexibility for electrode. The results of this study provides a simple method to produce an effective material for flexible pseudocapacitor electrodes for higher energy storage devices.
研究领域:
材料科学
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电化学
✓ 已验证
DOI
JOURNAL OF MEMBRANE SCIENCE
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2023
·
IF 9.5
Huixian Zhou,Yiqing Zeng,Zexian Low,Feng Zhang,Zhaoxiang Zhong,Weihong Xing
Developing cost-effective and high-efficient air purification materials for enhancing the indoor air quality has been an ongoing concern. Herein, MnO 2 /Co–C catalyst layers were wrapped on SiO 2 nanofiber by a combination of thermal pyrolysis and redox reaction method to prepare catalytic membranes (MCCS-x) for the efficient purification of indoor PM and HCHO. The core-dual-shell structure maintains the pore structure of the membrane, providing high gas permeability of 670 m 3 ·m −2 ·h −1 ·kPa −1 . Owing to the introduction of MnO 2 /Co–C enhanced the capture of PM, the optimized MCCS-2 exhibits high filtration efficiency of PM 0.3 and PM 2.5 (99.60% and 99.99%) with a low pressure drop (<80 Pa). In addition, MCCS-2 achieves 100% HCHO removal efficiency at room temperature due to its large specific surface area, high redox property and abundant Mn 4+ and oxygen species. The appropriate proportion of Mn/Co bimetallic sites synergy inhibits the formation of formate and carbonate intermediate species, thus MCCS-2 possesses excellent long-term catalytic stability than contrast sample (MCCS-3 and MS). This work demonstrates a new approach for the fabrication of high-performance catalytic membrane materials for indoor air purification.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Chengzhong Xiong,Runzhang Tao,Jian Lu,Shilong Li,Dong Zou,Yuqing Sun,Wenheng Jing
Efficient recovery of Li + from lithium-ion batteries (LiBs), which also include Co 2+ , Ni 2+ , or Mn 2+ in the cathode material, remains a formidable challenge because the sizes and physicochemical properties of these ions. Composite lamellar membranes are emerging as highly ion-selective nanochannels with controllable interlayers. Herein, Li + /Co 2+ was precisely separated through two-dimensional MXene/δ-MnO 2 composite nanochannels under an electric field. The nanochannels were constructed on tubular ceramic membranes via hydroxyl crosslinking. The membrane layer spacing can be extended to 5.7 Å by electrostatic repulsion between MXene and δ-MnO 2 nanosheets, which is suitable for Li + /Co 2+ separation. Under an electric field of 2 mA cm −2 , Li + /Co 2+ was nearly completely separated, with a high Li + flux of 0.0094 mol m -2 h −1 , and the energy consumption was ∼0.315 kW h (mol Li + ) -1 . Similarly, near-complete separation of Li + /Ni 2+ and Li + /Mn 2+ can be achieved at a current density of 2 mA cm −2 . The transport of Li + in solution was accelerated under a positive electric field and by partial dehydration in the nanopores. Meanwhile, the zeta potential was distinctly more negative in the composite membranes than in individual MXene or δ-MnO 2 . Consequently, Co 2+ was rapidly adsorbed on the negatively charged membrane surface through electrostatic interactions and complexation, forming a positively charged Co 2+ layer that electrostatically repelled further Co 2+ adsorption, ultimately achieving near-complete separation of Co 2+ . Owing to their stable and robust structure, the MXene/δ-MnO 2 membranes maintained high separation efficiency in acidic solutions containing Li + and Co 2+ and remained stable over eight cycles (up to 14 h) of ion separation under an electric field. This approach can potentially realize 2D membrane composites for efficient ion separation in practical applications.
研究领域:
材料科学
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环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2024
·
IF 7.5
Jie Yu,Manye Liu,Bo Wang,Chenxu Liang,Xuyi Wang,Kai Wang,Quanfang Lu
Graphical Flower-like α -MnO 2 nanospheres with assembled by dozens of nanosheets were fabricated using KMnO 4 as precursor via anode glow discharge electrolysis (AGDE), and then employed as a positive electrode material of supercapacitor to successfully light the light-emitting diode (LED). A novel green synthesis strategy–anode glow discharge electrolysis (AGDE) was employed for one-step preparation of α -MnO 2 in 2 g L −1 KMnO 4 solution, in which Pt needle and carbon rod were regarded as anode and cathode, respectively. The optimal preparation condition is 400 V for 60 min and the power consumption is below 45 W. The XRD, Raman spectra, XPS and EPR proved that α -MnO 2 with structural defects (oxygen vacancies) is obtained. SEM and TEM revealed that α -MnO 2 shows a flower-like nanospheres with a diameter of 165 nm, which is assembled by many nanosheets. A possible formation mechanism is that the MnO 2 is generated via the reduction of MnO 4 − by H⋅ and e aq − in plasma-liquid interface. Electrochemical test found that MnO 2 nanospheres exhibit a specific capacitance of 365 F g −1 at 1 A g −1 , and capacity retention of 79.8 % after 10,000 cycles at 5 A g −1 . The assembled asymmetric supercapacitor shows the maximum energy density of 23.1 Wh kg −1 at power density of 1.89 kW kg −1 . In brief, AGDE is a simple, facile and green technique for the synthesis of α-MnO 2 without adding extra chemicals, and prepared α -MnO 2 can be considered as an excellent candidate of electrode materials for supercapacitor.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Mengjie Pan,Huachen Lin,Lin Sun,Yulong Ying,Hong Jia,Yu Liu
Research into electrode materials that are low-cost, possess high capacity, and exhibit long cycle life is pivotal for the advancement of supercapacitor technology. Herein, a CoP/P-C/MnO 2 @CC composite is synthesized by solution impregnation and high temperature phosphating. The unique combination of nanotubes and MnO 2 nanosheets reduces ion and electron transmission distance and significantly increases active sites. The CoP/P-C/MnO 2 @CC electrode demonstrates a specific capacitance of 742.0 F g −1 at 1 A g −1 , a substantial improvement over the counterpart prior to KMnO 4 immersion (459.4 F g −1 ). Furthermore, an asymmetric supercapacitor based on the CoP/P-C/MnO 2 @CC electrode was assembled, achieving a high energy density of 93.12 Wh kg −1 at a power density of 800 W kg −1 . Meanwhile, the device maintains 77.3 % of its original capacity after 8000 cycles, demonstrating good cycle stability. This study not only presents an attractive electrode material with unique structure, but also provides a referential methodology for developing superior electrodes.
研究领域:
材料科学
·
能源存储技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）