查找使用阿拉丁产品的科研文献

Multifunctional Interfacial Engineering Enables Stable MnO2 Cathodes for Aqueous Zinc-Ion Batteries

Ziyang Cai,Mengqi Zhou,Weiliang Sun,Yanqiong Li,Huilin Pan

Rechargeable aqueous zinc-manganese dioxide (Zn-MnO2) batteries are one of the most promising candidates for large-scale energy storage due to their advantages of high safety, a high operating potential, and low cost. However, the unstable interface reactions and low electrical conductivity of the MnO2 cathode hold significant obstacles for the electrochemical performance of Zn-MnO2 batteries. Herein, we report a unique interfacial engineering approach to cooperatively tackle with Mn2+/MnO2 chemistry and build a conductive network at the electrode–electrolyte interface for the MnO2 cathode through dual-layer coating of ZIF-8/polypyrrole on MnO2 (ZPM). The outer ZIF-8 coating layer helps maintain a dynamically stable dissolution/deposition of Mn2+, whereas the electronic conductive polypyrrole inner layer establishes a robust conductive network. As a result, the ZPM cathode demonstrates an exceptional rate performance and a prolonged lifespan of 5000 cycles with a low attenuation of 0.00925% per cycle at 10C. The ampere-hour pouch cell of the ZPM cathode achieves a total capacity of 1068.4 mAh under a high areal capacity of 2.5 mAh cm–2, validating its practical viability. This dual-layer interfacial engineering strategy integrating Mn2+ dissolution/deposition regulation and electronic conductivity optimization provides an insightful pathway for addressing the complex issues of aqueous Zn-MnO2 batteries.

Yolk–shell-structured MnO2 microspheres with oxygen vacancies for high-performance supercapacitors

Yongsheng Fu,Xiangyu Gao,Daosong Zha,Junwu Zhu,Xiaoping Ouyang,Xin Wang

Yolk–shell-structured MnO2 microspheres with oxygen vacancies (ov-MnO2@MnO2) were successfully constructed by a facile three-step method. Morphological observations showed that the as-obtained ov-MnO2@MnO2 microspheres possessed distinctive yolk@void@shell configurations with an average diameter of 1.13 μm. Both the shell and yolk were assembled by a large amount of homogeneous MnO2 nanoparticles with an average diameter of 12 nm. The yolk–shell-structured ov-MnO2@MnO2 microsphere electrode exhibited a large specific surface area (259.83 m2 g−1) and good conductivity, thus it achieved high specific capacitance (452.4 F g−1 at 1 A g−1 and 316.1 F g−1 at 50 A g−1), excellent cycling stability (10 000 cycles) and superior rate capability (∼79.2% and 69.9% of the initial capacity at 20 A g−1 and 50 A g−1, respectively). It is noted that the asymmetric supercapacitor (ASC) composed of yolk–shell-structured ov-MnO2@MnO2 microspheres (as the positive electrode) and commercial activated carbon (as the negative electrode) can deliver a high energy density of 40.2 W h kg−1 and a maximum power density of 22.28 kW kg−1. The superior electrochemical performance of ov-MnO2@MnO2 is mainly ascribed to the unique yolk@void@shell nanostructure, the presence of oxygen vacancies in the crystal lattice and the synergistic effect of the individual components of the hybrid.

Efficient Degradation of 2,4-Dichlorophenol on Activation of Peroxymonosulfate Mediated by MnO2

Liu Jingliang,An Fengxia,Li Mei,Yang Lu,Wan Jinzhong,Zhang Shengtian

Sulfate radical based-advanced oxidation process has received increasing interest in the remediation of wastewater and contaminated soil. In this study, degradation of 2, 4-dichlorophenol (2, 4-DCP) was investigated over peroxymonosulfate (PMS) activation by MnO 2 , which was prepared by liquid-phase oxidation method. The prepared MnO 2 was characterized by transition electron microscopy, X-ray diffraction, N 2 adsorption–desorption, and X-ray photoelectron spectroscopy. Characterization results showed that α-MnO 2 exhibited the highest surface area and Mn (III) content. The PMS activation by MnO 2 in 2, 4-DCP degradation followed the order of α-MnO 2  >  γ-MnO 2  > β-MnO 2 , which is dependent on the properties of MnO 2 including crystal structure, surface area and Mn (III) content. Influences of initial concentration of 2, 4-DCP, PMS and MnO 2 dosage, pH and co-existing inorganic ions on the degradation were examined. Electron paramagnetic resonance (EPR) and quenching experiments with ethanol and tert-butanol suggested that sulfate radicals were the dominant radicals in the process. Findings in this study indicated that α-MnO 2 was an attractive catalyst for activation of PMS to degrade 2, 4-DCP in aqueous solution.

Synergistic photothermal/photodynamic suppression of prostatic carcinoma by targeted biodegradable MnO2 nanosheets

Dewang Zeng,Lei Wang,Lu Tian,Shili Zhao,Xianfeng Zhang,Hongyan Li

Treatment of high-nitrate wastewater mixtures from MnO2 industry by Chlorella vulgaris

Huan Li,Yun Zhang,Jiuyi Liu,Zhensheng Shen,An Li,Tian Ma,Qian Feng,Yingqiang Sun

The aim of this work was to study the biotreatment of mixed wastewaters collected from two points of MnO 2 industry by Chlorella vulgaris . Their growth rates in four mixed wastewaters with mass ratio of wastewater 1 # :2 # of 20:1, 50:1, 100:1, and 200:1 were characterized, and the lag phase was shortened with increase of nitrate concentrations. The N, P, and metal removal kinetics were quantified each other day to evaluate the bio-treatment efficiencies of high-nitrate wastewaters from MnO 2 industry. 84.68% and 98% of N, P has been removed. The Ca, Zn, Mn, and Si in mixed wastewaters was removed with maximum removal efficiencies of 97.91%, 99.37%, 99.44%, and 81.68%, respectively. The compositions of Chlorella vulgaris cultured in mixed wastewaters, including proteins, lipids, ash contents, and carbohydrates, were investigated in detail. The optimum HHV of Chlorella vulgaris about 18 MJ/Kg presented a potential to decrease the cost of algal biofuel.

Rapidly regenerated CNC/TiO2/MnO2 porous microspheres for high-efficient dye removal

Yingkun Song,Min Jiang,Lijuan Zhou,Hongsheng Yang,Jianming Zhang

The cellulose nanocrystal (CNC)/transition metal oxide hybrid porous microspheres usually have high adsorption performance and degradability, and show promising applications in the field of wastewater treatment. However, single metal oxides are limited by the forbidden band width and electron-hole complexation, and often fail to achieve good effluent treatment. Herein, a CNC/manganese dioxide/titanium dioxide porous microspheres are prepared by the combination of bubble template and ionic crosslinking between sodium alginate and Ca 2+ ions as a matrix. Based on the synergistic effect of two kinds of transition metal oxide , the degradation efficiency of CNC/MnO 2 /TiO 2 porous microspheres for methylene blue is as high as 97.0%, showing easy recovery process and rapid regeneration of this material. Besides, its maximum removal of dyes reaches up to 310.2 mg/g, which is much higher than most CNC based adsorption materials. The concept of concerted catalysis can to explain the origin for excellent performance of as-prepared hybrid microspheres.

Process dependent graphene-wrapped plate-like MnO2 nanospheres for high performance supercapacitor

Chunliang Liu,Dayong Gui,Jianhong Liu

Two kinds of MnO 2 /graphene nanocomposites (M1 and M2) were synthesized by two different reaction procedures. M1 was synthesized as follows: the plate-like MnO 2 /graphene nanocomposite was obtained by using hydrazine reduction of MnO 2 /graphene oxide. M2 was formed as follows: the plate-like MnO 2 nanospheres was synthesized on the graphene nanosheet which was reduced by hydrazine reduction of graphene oxide. The M1 have a good electrochemical performance and the average capacitance is as high as 250.6   F   g −1 at 1   A   g −1 in 1   mol   L −1 Na 2 SO 4 electrolyte, which is higher than that of the M2 (206.8   F   g −1 ).

Patterning Islandlike MnO2 Arrays by Breath-Figure Templates for Flexible Transparent Supercapacitors

Yizhou Wang,Weixin Zhou,Qi Kang,Jun Chen,Yi Li,Xiaomiao Feng,Dan Wang,Yanwen Ma,Wei Huang

Although plenty of active materials could be used as supercapacitor electrodes, only limited ones have been engineered to construct transparent supercapacitors. Specially, it is a great challenge to make opaque metal oxides, which often own high energy density, into transparent films. Here, we demonstrate a novel approach to fabricate transparent MnO2 films for flexible transparent supercapacitors. By utilizing breath-figure polymer films with ordered pores as template, arrays of MnO2 islands were electrochemically deposited, with high light transmission. The thickness and interspace distance of MnO2 island arrays could be adjusted by tuning deposition time so that the capacitance and transparency of the electrodes are changed accordingly. Such island array structure can effectively eliminate the internal stress existing in the composite film to avoid cracks during bending operation. The assembled transparent supercapacitor shows a transmittance of 44% at 550 nm and can yield a high capacitance of 4.73 mF/cm2 at a current density of 50 μA/cm2, demonstrating high flexibility and stability.

Probing NAD+/NADH-dependent biocatalytic transformations based on oxidase mimics of MnO2

Shuyun Zhu,Cuihua Lei,Jing Sun,Xian-En Zhao,Xiao Wang,Xiaolu Yan,Wei Liu,Hua Wang

In the present study, a novel colorimetric sensing platform was constructed for probing the NAD + /NADH-dependent biocatalytic transformations. Manganese dioxide (MnO 2 ) nanosheets as an oxidase-mimicking nanomaterial could directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) into oxTMB without the need of H 2 O 2 . Importantly, it was found that NADH could easily trigger the decomposition of MnO 2 nanosheets, causing the decrease of solution absorbance. This is demonstrated by the enzyme catalysis reactions of two dehydrogenase models, ethanol dehydrogenase (ADH) and lactate dehydrogenase (LDH), where NADH is formed and consumed, respectively, in their physiological enzymatic reactions. A MnO 2 -TMB sensing platform was thereby proposed for the analysis of their catalytic reaction substrates including ethanol and pyruvic acid. The detection limits of ethanol and pyruvic acid can reach 5.0 μM and 100 nM, respectively. The developed optical biosensing platform can be used to develop other dehydrogenase-based biosensors followed by monitoring their substrates.

Single particle detection based colorimetric melamine assay with MnO2-modified gold nanoparticles

Xiang Yuan,Huiling Zhang,Xiang Yuan,Guojiang Mao,Lin Wei

In this work, we demonstrate a simple and label-free single particle detection (SPD) method for the quantification of melamine (Mel) based MnO 2 -modified gold nanoparticles (Au@MnO 2 NPs). Without Mel, MnO 2 shell of Au@MnO 2 NPs are able to be directly decomposed by gallic acid. In the existence of Mel, the decomposition process is restrained due to the strong hydrogen bonding between Mel and gallic acid. The selective etching of MnO 2 shell on AuNPs surface results in evident color change from single Au@MnO 2 NPs. Through quantitatively enumerating the number of color coded particles, trace amounts of Mel can be accurately detected. A linear range from 0.02 to 1 μM (R 2  = 0.98) and a limit of detection of 16.7 nM are acquired. In milk sample, satisfactory recovery was acquired. Therefore, the SPD method is expected to be used for the detection of various chemical contaminants in food.

Effect of MnO2 Morphology on Kinetics and Stability in Zinc-Ion Batteries

Ning Gao,Yang Song,Chang Li,Chaoquan Hu

Research on zinc-ion batteries (ZIBs) with manganese-based cathodes has been severely hindered by their poor cycle stability. This study explores the fundamental parameters that affect the cycle stability of battery systems from a structural stability perspective. MnO2 electrodes with different classical morphologies and sizes were synthesized via a temperature-controlled coprecipitation strategy. The effects of the morphology and size of the MnO2 on the overall electrical properties and kinetics of ZIBs were analyzed and compared. The one-dimensional nanofibrous α-MnO2 produced using this method exhibited the most stable nanostructure with a favorable aspect ratio, which resulted in faster chemical kinetics. A more uniform particle distribution and better aspect ratios not only enabled a faster ion migration rate but also affected the remolding of the anode morphology. After 2000 cycles at a high current density of 1 A g–1, the material maintained an excellent discharge-specific capacity, highlighting it as a promising electrode material for ZIBs. The construction of nanoenergy materials with controllable morphologies and sizes will significantly advance battery applications.

Regeneration of granular activated carbon adsorbent by peroxymonosulfate activation with MnO2/MnFe2O4

Juntong Liu,Ruoyu Sun,Yinsu Wu,Shengtao Xing

The regeneration of spent adsorbent is crucial in terms of environmental and economic aspects. In this study, MnO 2 /MnFe 2 O 4 was synthesized by an impregnation-precipitation method and investigated as a peroxymonosulfate (PMS) catalyst for the regeneration of granular activated carbon (GAC) after adsorption of ofloxacin (OFL). MnO 2 /MnFe 2 O 4 exhibited high catalytic activity for the regeneration of GAC with PMS, and the adsorbed OFL was effectively removed from GAC surface. Singlet oxygen was found to be the dominant reactive species in this process, while O 2 •− and SO 4 •− participated in the degradation of intermediates. At neural pH, the regeneration efficiency of the spent GAC after the adsorption of OFL, tetracycline hydrochloride, ciprofloxacin and methylene blue reached 100 %, 100 %, 87.2 % and 84.2 %, respectively. MnO 2 /MnFe 2 O 4 and GAC exhibited good stability and reusability in this process, and the regeneration efficiency was still above 90 % in the fifth cycle. The results suggest the potential application of PMS activation with magnetic catalyst in the regeneration of GAC after adsorption of organic pollutants .