MICROCHIMICA ACTA
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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
·
分析化学
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产品关联
DOI
PubMed
高影响因子
Nanoscale
·
2020
·Vol. 12
·期 47
·24196-24205
·
IF 6.895
Heng Zhang,Peigen Zhang,Long Pan,Wei He,Qi Qi,Zhuoheng Bao,Li Yang,Wei Zhang,Michel W. Barsoum,ZhengMing Sun
Lithium–sulfur (Li–S) batteries are regarded as potential next-generation energy storage systems due to their high theoretical energy densities. However, the dissolution of lithium polysulfides (LiPSs) upon cycling can result in severe capacity degradation. Achieving high rate capabilities with good cycling stability remains a huge obstacle for the practical implementation of Li–S batteries. Here we developed a novel, multifunctional, hierarchical structure by self-assembling core–shell MnO2 nanorods @ hollow porous carbon with 2D Ti3C2Tx nanosheets, labelled as MCT, as an efficient polysulfide mediator for Li–S cathodes. The integration of the polar MnO2 core and hollow porous carbon shell captures LiPSs two ways: physical confinement and chemisorption. The conductive Ti3C2Tx nanosheets construct a continuous and conductive network, which not only promotes charge transfer and ion diffusion but also boosts LiPS adsorption and conversion. Based on these merits, the MCT/S cathode delivers good rate capability (688 mA h g−1 at 2.0C) and outstanding long-term cyclability (0.044% capacity decay per cycle over 600 cycles at 2.0C).
研究领域:
材料科学
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能源存储技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lili Cao,Yuxiang Chen,Shane Feng,Yanli Su
To reduce the dielectric loss of MXene/PVDF composites near the percolation threshold, a MnO 2 /MXene hybrid structure was successfully synthesized via an ultrasonic-assisted solution process, and MnO 2 /MXene/PVDF composite films were prepared by a solution casting method. The effects of different amounts of MnO 2 nanorods on the microstructure, thermal stability, dielectric properties and mechanical properties of the composite films were investigated. At 1 kHz, the dielectric constant of 7 wt% MnO 2 /MXene/PVDF is 37.3, and the dielectric loss is as low as 0.05. The electric modulus curve, Nyquist curve and equivalent analog circuit of the composites revealed strong interface polarization and microcapacitance effects in the composites. In addition, the composite films exhibit excellent mechanical properties, and the storage modulus of the composite film loaded with 10 wt% MnO 2 is 1990.5 MPa, which is 3.44 times that of pure PVDF. This study confirms that incorporating MnO 2 nanorods into MXene/PVDF composites is an effective approach for fabricating high-performance dielectric composites.
研究领域:
材料科学
·
电介质材料
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产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2013
·
IF 2.072
Hongtao Guan,Jianbin Xie,Gang Chen,Yude Wang
One-dimensional α-MnO 2 nanorods were fabricated by using low-temperature water-bathing chemical precipitation method at 80 °C. The crystalline structures, morphological evolution process and microwave absorption properties were systematically investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and measurement of electromagnetic parameters. The results show that the morphological structures and electromagnetic properties have close relationship with the reaction time. With the prolonging of the treatment time, the as-synthesized products turn from microspheres constituted of tiny dendrites to nanorods with diameters of 20–30 nm and lengths up to 1–2 μm. The electromagnetic characterization shows that the dielectric constants and magnetic permeability values show decreasing trends with the increasing frequency, however, the dielectric and magnetic loss tangents all increase with frequency. The electromagnetic absorption properties of the products have close relationship with the morphologies and thicknesses of the samples. With a thickness of 3 mm, an absorbing peak value of −25 dB was achieved for the sample treated for 24 h. The microwave absorption properties of MnO 2 can be attributed mainly to interfacial polarization, space charge polarization and relaxation phenomena.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2022
·
IF 14.224
Ping Li,Shujuan Zhan,Lan Yao,Ya Xiong,Shuanghong Tian
Herein we reported the first example of preparing α-MnO 2 by selective acid etching from Mn-containing spinel. The defects, facet, and surface area of α-MnO 2 were cooperatively engineered by an all-in-one acid etching method to enhance the defect accessibility to the reactants. The obtained highly porous α-MnO 2 nanorods have rich defects of Mn 3+ (24.9%) and oxygen vacancies (31.4%), mainly active crystal facets of (110), and an ultrahigh surface area of 271.1 m 2 /g. With α-MnO 2 nanorods as the catalysts, more than 90.9% of 4-chlorophenol can be degraded within 12 min by catalytic ozonation in a wide work pH of 4.5–10.5. The experiments and DFT theory calculations reveal that α-MnO 2 with (110) facet promotes the adsorption and activation of ozone directly over the defects or indirectly over H 2 O adsorbed on the defects. Thus, more reactive oxygen species (e.g., •OH, •O 2 - , 1 O 2 , surface *O) are generated and get involved in pollutant degradation. This work provides a facile method to maximize the defect accessibility, and a deeper mechanistic study to understand the roles of the defects.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
RUSSIAN JOURNAL OF GENERAL CHEMISTRY
·
2024
·Vol. 94
·期 3
·616-629
·
IF 0.9
Chen L.,Lian Q.,Li M.,Yu H.,Lv Y.,Guo M.,Zheng X.
Abstract Rod-shaped MnO 2 was synthesized by hydrothermal method. Ag@MnO 2 NRs were prepared with the Ag nanoparticles grown on the surface of rod-shaped MnO 2 by different reducing agents. The Ag@MnO 2 NRs were characterized by X-ray diffractometry, scanning and transmission electron microscopy, as well as X-ray photoelectron spectroscopy. The catalytic performance, catalytic mechanism and kinetic equation of the Ag@MnO 2 NRs were investigated. The as-prepared Ag@MnO 2 NRs were endowed with oxidase-like activity to catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue product without H 2 O 2 . Due to the inhibition of hydroquinone (HQ) on TMB oxidation, a simple, rapid, sensitive, and selective colorimetric sensor was set for the detection of HQ concentration in actual water. This method was established with an excellent linear range from 5–30 μM and a low detection limit of 1.7 μM. The colorimetric means could be availably used for the detection of HQ in river water samples and the RSD < 4.97%. The above results illustrated that the Ag@MnO 2 NRs had a great application prospect in environmental detection.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Hao Zhou,Xiaoying Zhu,Baoliang Chen
A novel magnetic catalytic composite (MBM) was developed by compositing α-MnO 2 with a magnetic biochar containing Fe 3 O 4 . XRD and EDS confirmed the crystalline structure and the chemical composition of MBM, while the one-dimensional α-MnO 2 nanorods were observed on MBM by SEM. 4-chlorophenol as a typical toxic chlorinated organic compound was selected as the model pollutant. Even the MBM composite (MnO 2 content: 0.2 g/L) needed the same time (120 min) as the pure α-MnO 2 nanorods (0.2 g/L) to completely remove the 4-chlorophenol (10 mg/L) with overdosed peroxydisulfate (PDS), MBM indicated faster pollutant removal rate than the pure α-MnO 2 nanorods in the first 100 min. It is possible that the adsorption of 4-chlorophenol by biochar might shorten the migration pathway of the generated active species to the pollutants, resulting the boosted removal rate. MBM was stable in the neutral environment which was desirable for the efficient pollutant removal. Both the radical quenching tests and the EPR spectra identified the main active specie generated by activation of PDS through MBM was singlet oxygen possibly generated by recombination of superoxide ions from the metastable manganese intermediates at neutral pH. TOC data of the effluent ensured 63.5% of the pollutant molecules were completely mineralized after the degradation. The applied magnetic field could recover MBM easily for reuse. This work shed lights on the preparation of highly efficient and environmentally friendly catalytic composites for PDS activation in persistent pollutant removal.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
IONICS
·
2021
·Vol. 27
·期 9
·3943-3950
·
IF 2.817
Cai Xinhao,Li Hanghang,Li Jing,Yan Huihui,Liu Yiwen,Yu Haoxiang,Yan Lei,Zhang Liyuan,Shu Jie
Rechargeable aqueous Zn/MnO 2 battery with mild electrolyte is exceedingly suitable for massive electrochemical applications due to its eco-friendliness and high safety. However, cycle stability is a crucial question in the practical application. Besides, the mechanism involved in energy storage is still controversial. Here, we show a Zn/MnO 2 battery with excellent cycle stability and provide the reasonable explanation of the operating mechanism. In this battery, the mild aqueous ZnSO 4 solution containing MnSO 4 and Na 2 SO 4 additives serves as the electrolyte and the β-MnO 2 nanorods serve as the cathode. As presented in the electrochemical tests, the specific capacity of β-MnO 2 nanorods is as high as 323.5 mA h g −1 , and its capacity retention is 94% after 1000 cycles at 3 A g −1 . The proposed energy storage mechanism is related to the reversible conversion reaction between β-MnO 2 and MnOOH. Therefore, the application of β-MnO 2 nanorods in aqueous Zn-ion battery has broad development prospects. Graphical abstract
研究领域:
电化学
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材料科学
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能源存储
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无机化学
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纳米材料
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Xiaowen Chen,Zihan Xu,Sai Guo,Bo Sun,Qijian Li,Qingkun Meng,Fuxiang Wei,Jiqiu Qi,Yanwei Sui,Peng Cao
Improving electrical conductivity and increasing the active site are important directions for improving the technology of manganese-based cathode materials for zinc ion batteries (ZIBs). In this paper, cobalt-doped and oxygen-vacancy coupled MnO2 nanorods (Vo-CMO) were prepared by defect engineering and an ion doping strategy as cathode materials for rechargeable ZIBs. Oxygen vacancies can increase the defect density of the material and provide more migration paths for zinc ions, thereby increasing the electrochemical activity and improving the specific capacity. The introduction of cobalt can adjust the electronic structure of manganese oxide, change the Fermi level of the material, and promote the generation and transmission of charge carriers, thereby increasing the charge transfer rate and increasing the conductivity of the material. The synergistic effect among them can improve the diffusion kinetics of zinc ions, thereby increasing the capacity and cycle stability of the material. The Vo-CMO has better Zn2+ storage capacity of 295.6 mAh·g–1 at 0.1 A·g–1. The reaction mechanism of Vo-CMO material was H+/Zn2+ coinsertion through galvanostatic current intermittent titration (GITT) and ex situ experiments. In addition, the Vo-CMO material assembled the flexible quasi-solid ZIB. The synergistic effect of cobalt doping and oxygen vacancy can provide a new way to develop water-based ZIBs.
研究领域:
材料科学
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电化学
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储能
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纳米材料
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电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）