ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Qi Chen,Wenjing Wei,Jingjing Tang,Jinkun Lin,Songjun Li,Maiyong Zhu
Yolk@shell nanocomposites with delicate composition and tailored structure usually exhibit great potential in various areas. In the present study, the synthesis of yolk@shell Fe 3 O 4 @MnO 2 microspheres was reported using core@shell Fe 3 O 4 @polydopamine (Fe 3 O 4 @PDA) as starting materials. This novel approach is based on the reductive property of the PDA derived carbon shell. The new shell of MnO 2 was synthesized by reaction of PDA derived carbon and KMnO 4 . The Fe 3 O 4 @MnO 2 yolk@shell microsphere was successfully used as electrode material for supercapacitor and delivers a high specific capacitance of 715 F/g at 1 A/g with a good rate capability (450 F/g at 10 A/g). Furthermore, the Fe 3 O 4 @MnO 2 yolk@shell microsphere was also used as the positive electrode for asymmetric supercapacitors (ASC), wherein N doped carbon from PDA was applied as negative electrode. As a result, the energy density of the constructed ASC device was up to 31.3 Wh/kg at a power density of 750 W/kg. Meanwhile, the Fe 3 O 4 @MnO 2 //N-pC (PDA derived N-doped porous carbon) device offers an excellent cycling stability (94.7% of capacitance retention after 5000 cycles). Such distinguish capacitive performance is undoubtedly related to the electrochemical actuation of the yolk@shell microsphere structure and their structural integrity, where the void between the shell and yolk may relieve the volume change of the electrode. Considering the efficiency and simplicity of the synthetic procedure, it is expected that the present method might be suitable for preparation of yolk@shell composite with other components and structures, offering potential in various applications.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2025
·Vol. 236
·期 7
·1-16
·
IF 3
Jiang Yinying,Yu Jiang,Huang Zhi,Yu Jie,Deng Siwei,Zhu Weiwei,Zeng Zixin
Metformin (MET), recognized as the most extensively consumed pharmaceutical globally, exhibits minimally metabolized and is predominantly excreted unchanged. To remove MET from water, this study synthesized Fe 3 O 4 @MnO 2 (FM) catalysts, which could be easily recoverable using magnets. Notably, Fe 3 O 4 nanospheres, characterized by their superior crystallinity, significantly altered the morphology and structure of the externally wrapped MnO 2 . This modification resulted in an expanded surface area and an increased number of active sites. Furthermore, ultrasound (US) was employed to assist in peroxymonosulfate (PMS) activation, ensure effective dispersion of FM-5, and enhance the homogeneity of the reaction system. The synergistic application of US and FM-5 successfully activated PMS, achieving a remarkable MET degradation efficiency of 98.89% within 80 min, predominantly via a pathway governed by ·O 2 − and 1 O 2 . The FM-5/US/PMS system demonstrated robust adaptability under various environmental conditions. An analysis of the correlation mechanism revealed enhanced MET decomposition under alkaline conditions, thereby broadening the pH adaptation range of FM-5/US/PMS. Using density functional theory (DFT) calculations and HPLC–MS detection to propose degradation products, this study identified a product with comparatively lower toxicity. This work could offer a reference for further development of high performance and eco-friendly catalyst. Graphical
研究领域:
环境科学
·
材料科学
·
药学
✓ 已验证
产品关联
DOI
高影响因子
Materials Chemistry Frontiers
·
2022
·Vol. 6
·期 14
·1938-1947
·
IF 8.683
Chengyu Tu,Xuan Li,Congcong Lu,Qiao Luo,Tie Li,Maiyong Zhu
Designing efficient, durable, and affordable electrodes for supercapacitors is indispensable for utilizing clean and renewable energy resources. Herein, a three-step sequential process, including two hydrothermal procedures followed by an etching treatment, was developed to synthesize Fe3O4@MnO2 hollow nanospheres (Fe3O4@MnO2-HNS) using solid silica as a hard template. Fe3O4@MnO2-HNS has the largest specific surface area (121.99 m2 g−1) due to a double hollow structure compared to other samples. The as-prepared Fe3O4@MnO2-HNS exhibited superior electrochemical performance as compared to pristine hollow nanospheres of either Fe3O4 or MnO2. When applied to practical asymmetric supercapacitor devices (Fe3O4@MnO2-HNS as a positive electrode and activated carbon (AC) as a negative electrode), Fe3O4@MnO2-HNS//AC exhibited prominent performance, such as a high capacity of 168.81 C g−1 (375.14 F g−1) at 0.5 A g−1, a large energy density of 15.84 W h kg−1 at a power density of 803 W kg−1, and an excellent stable charge–discharge durability of 70.6% over 5000 cycles at 2 A g−1. We envision that Fe3O4@MnO2-HNS may be a promising alternative for applications in energy storage and electrocatalysis where discrete electrochemical performances are desired.
研究领域:
材料科学
·
能源存储
·
纳米技术
✓ 已验证
DOI
高影响因子
Analytical Methods
·
2014
·Vol. 7
·期 4
·1300-1306
·
IF 1.938
Yuhao Xiong,Siheng Chen,Fanggui Ye,Linjing Su,Cong Zhang,Shufen Shen,Shulin Zhao
In this paper, magnetic core–shell nanoflowers Fe3O4@MnO2 were fabricated via a solvothermal method. We demonstrated that the as-synthesized magnetic nanoflowers Fe3O4@MnO2 possess intrinsic oxidase-like activity in a wide pH range and can catalytically oxidize 4-aminoantipyrine (4-AAP) and phenol substrates to form pink color products without the requirement for additional oxidizing agents. On the basis of this phenomenon, a simple colorimetric method for the determination of phenol was developed. A wide linear detection range can be obtained from 1.0 μM to 120 μM (R2 = 0.9962) with a detection limit of 0.15 μM. And the method was applied to determine phenol in wastewater with good recoveries ranging from 96.0 to 101.5%. Furthermore, benefitting from chemical stability and easy recovery (by simple magnetic separation) of Fe3O4@MnO2, the oxidase mimetics have excellent reusability and reproducibility in cycle analysis.
研究领域:
材料科学
·
分析化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Jianhui Zhao,Jie Liu,Ning Li,Wei Wang,Jun Nan,Zhiwei Zhao,Fuyi Cui
In this study, magnetic Fe 3 O 4 -MnO 2 nanoplates were successfully synthesized by a facile hydrothermal process in order to remove bivalent heavy metals from water. The Fe 3 O 4 part facilitated the reclamation of the adsorbent. Meanwhile, the modification by amorphous MnO 2 could significantly enhance the specific surface area of Fe 3 O 4 -MnO 2 and decrease the point of zero charge, thus ensured the good adsorption capacity for metal cations. The adsorption isotherms and kinetics of the five metal ions on Fe 3 O 4 -MnO 2 and the pH effect on removal efficiency were detailedly investigated. Sips isotherm was the most suitable model to describe Pb 2+ , Cu 2+ , Cd 2+ and Zn 2+ adsorption on Fe 3 O 4 -MnO 2 , while Temkin, Redlich-Peterson and Langmuir models showed a higher fitting degree for Ni 2+ . The adsorption capacities of Pb 2+ , Cu 2+ , Cd 2+ , Zn 2+ and Ni 2+ on Fe 3 O 4 -MnO 2 were 208.17, 111.90, 169.90 100.24 and 55.63 mg/g, respectively. Kinetic data were better fitted to pseudo-second-order model ( R 2 > 0.99), indicating a dominant role of chemisorption. Further analysis of infrared spectra demonstrated that the adsorption process was achieved mainly by ion exchange and complexation. The adsorption rates and preference ranking of metal ions on Fe 3 O 4 -MnO 2 were in the same order: Pb 2+ > Cu 2+ > Cd 2+ > Zn 2+ > Ni 2+ . Moreover, the adsorbent showed good recyclability and excellent ability of neutralizing the solutions by surface protonation and deprotonation. Overall, the reported results here have significant implications for removing metal cations from water in practice.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Jie Liu,Zhiwei Zhao,Penghui Shao,Fuyi Cui
Heterogeneous catalysts with low cost, little hazardous, high effective and facile separation from aqueous solution are highly desirable. In this study, magnetic Fe 3 O 4 –MnO 2 core–shell nanocomposites with various Fe/Mn weight ratios were synthesized through a facile one pot method and then characterized. These as-synthesized solids were applied to activate the peroxymonosulfate (PMS) for 4-chlorophenol degradation. The sample 3 with a Fe/Mn molar ratio of 4:1, which can be separated conveniently through external magnetic field, exhibited higher activity than other Fe 3 O 4 –MnO 2 nanocomposites, pure MnO 2 and physical mixture of Fe 3 O 4 and MnO 2 . The effects of operational parameters on the catalytic activity of sample 3, including initial Oxone and pollutant dosage, pH and catalyst dosage, were assessed. The catalyst had high stability and good reusability according to five successive repeated reaction. The reactive radicals generated in the PMS/Fe 3 O 4 –MnO 2 nanocomposites system were sulfate radical (SO 4 − ) and hydroxyl radical ( OH). The enhancement of the nanocomposites may be attributed to the interaction of Fe 3 O 4 with MnO 2 on the basis of the in situ ATR-FTIR analysis and XPS spectrum.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
Nanoscale
·
2025
·
IF 5.1
Huangying Guo,Wenyu Wan,Pengcheng Deng,Yang Luo,Xing Zhou
Cross and secondary electromagnetic pollution is a major challenge in current electromagnetic interference (EMI) mitigation. In this study, Fe3O4@MnO2 composite microspheres and AgNWs were prepared using modified solvothermal and hydrothermal methods. By optimizing the fabrication process and structural design of electromagnetic shielding composite films, we successfully constructed a composite film with superior shielding performance and reduced thickness. The Fe3O4@MnO2 composite exhibited an SEA/SET ratio of 83.32%, along with a high absorption coefficient A, indicating its dominant role in electromagnetic wave absorption, thereby mitigating excessive reflection. Results demonstrated that the gradient network-structured film possessed significantly enhanced electromagnetic wave absorption and attenuation capabilities compared to other three composite materials. The SEA/SET of the gradient network-structured film reached 86%, with a maximum SET of 58.65 dB. This hierarchical structure not only improves shielding effectiveness at reduced thickness but also enhances absorption, achieving the ultimate goal of high absorption with low reflection while minimizing resource consumption.
研究领域:
材料科学
·
电磁学
·
纳米技术
·
复合材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Tong Ding,Wenxiao Zhao,Yuqing Sun,Shilong Li,Tianxiang Yu,Wenheng Jing
In this work, a novel 2D Fe 3 O 4 -MnO 2 hollow fiber ceramic membrane (HFCM) with both excellent separation performance and high catalytic activity was constructed. The Fe 3 O 4 nanoparticles were deposited on 2D MnO 2 nanoplates to increase the Mn 3+ content, and then the nanoplates were pressure-driven and sintered on the surface of the hollow fiber ceramic supports to obtain 2D Fe 3 O 4 -MnO 2 -HFCMs. Electron spin resonance analysis confirmed that hydroxyl radicals and superoxide radicals played a major role in oxidative degradation and tetracycline hydrochloride (TCH) removal was 86.9 %. Noteworthily, TCH was concentrated on the membrane interface due to the concentration polarization effect, which increases the probability of binding free radicals from the catalytic membrane layer, thus enhancing the catalytic performance and the anti-fouling capability of the membrane. The 2D Fe 3 O 4 -MnO 2 -HFCM can be applied in wastewater treatment due to its superior catalytic ozonation activity and high separation performance.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Mingtao Qiao,Xingfeng Lei,Yong Ma,Lidong Tian,Wenbin Wang,Kehe Su,Qiuyu Zhang
Functional composite microspheres with porous Fe 3 O 4 cores and hierarchical MnO 2 shells have been synthesized successfully via a two-step hydrothermal method . X-ray diffraction was employed to determine the crystal forms of samples. The morphologies and microstructures of Fe 3 O 4 nanoparticles and Fe 3 O 4 @MnO 2 composite microspheres were observed by the scanning electron microscope and transmission electron microscope. It can be seen that hierarchically structured MnO 2 shells have coated Fe 3 O 4 nanoparticles, and the shell thickness is about 140–160 nm. The BET specific surface area and porosity were estimated by the N 2 absorption-desorption isotherms and the magnetic properties were measured by the vibrating sample magnetometer . As-synthesized Fe 3 O 4 @MnO 2 composite microspheres have a BET specific surface area of 167 m 2 /g, and the pore width is mainly distributed in the mesoporous range, especially from 2.0 nm to 12.0 nm. Investigations of microwave absorbing properties manifest that Fe 3 O 4 @MnO 2 composite microspheres with loading 10% weight fraction possess the strongest RL peak of −42.6 dB (5.7 GHz) at the matching thickness 4.0 mm, and Fe 3 O 4 @MnO 2 composite microspheres with loading 20% weight fraction have a broader absorbing bandwidth (10.2–15.0 GHz and 15.5–17.3 GHz) at the matching thickness 1.5 mm. Achieving the advantages of intensive absorption, wide effective absorbing bandwidth band and intrinsic lightweight feature, porous core-shell Fe 3 O 4 @MnO 2 composite microspheres are believed to be more promising in the application of microwave absorption.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ACS ES&T Water
·
2020
·
IF 0
Limei Dong,Yiming Li,Dafan Chen,Xiuping Chen,Dan Zhang
The hierarchically structured Fe3O4-MnO2-ZIF-8 composite was successfully synthesized and applied to activate peroxymonosulfate (PMS) for the degradation of bisphenol A (BPA) and other organic pollutants for the first time. Catalytic experiments revealed that the as-prepared Fe3O4-MnO2-ZIF-8 showed highly efficient catalytic activity and deep mineralization for BPA because of the loading of ZIF-8. When 60 mg/L BPA was degraded by the Fe3O4-MnO2-ZIF-8/PMS system, the removal efficiency of BPA reached 100% within 15 min and the TOC removal efficiency reached 80% within 9 min, values that were much higher than those of the catalysts reported recently. Fe3O4-MnO2-ZIF-8 can be separated conveniently from the aqueous phase under magnetic field control and shows better recyclability. Simultaneously, the Fe3O4-MnO2-ZIF-8/PMS system shows an excellent removal capability for other organic pollutants, such as phenol, tetracycline, p-hydroxybenzoic acid, and rhodamine B. Through radical quenching experiments and electron paramagnetic resonance tests, the mechanism of activation of PMS by Fe3O4-MnO2-ZIF-8 was investigated. ZIF-8 loaded on the surface of the Fe3O4-MnO2 composite can accept electrons generated from the Mn(II)/Mn(III)/Mn(IV) redox conjugate triplet and react with PMS to generate more •OH and SO4•–, thus significantly enhancing the catalytic performance. Additionally, on the basis of GC-MS analysis, the intermediates in the process of BPA degradation were tested and the possible degradation pathway was determined. This study indicates that Fe3O4-MnO2-ZIF-8 is a highly efficient catalytic material for PMS-based AOPs for the removal of various pollutants from water.
研究领域:
环境科学
·
催化材料
·
水处理技术
✓ 已验证
DOI
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 47
·期 3
·1094-1104
·
IF 3.925
Hui Luo,Yang Han,Kaiyuan Hu,Jia Li,Dickon H. L. Ng,Xiaodi Ma,Kairui Luan,Mingkang Yang
Herein, we demonstrate a novel Fe3O4@MnO2@HKUST-1 magnetic micromotor with excellent peroxidase-like activity for highly efficient colorimetric detection and degradation of hydroquinone. Such micromotors had unique flower-like morphology with highly exposed active sites. The resulting MnO2-based micromotor was propelled by O2 bubbles generated from hydrogen peroxide fuel catalyzed by MnO2, and the velocity could be adjusted by the H2O2 fuel concentration. The self-propelled motion of the Fe3O4@MnO2@HKUST-1 could effectively increase the collision probability between active sites and pollutant molecules, and thus, enhanced the sensitivity of the colorimetric detection as well as the degradation efficiency. These excellent results confirm that this Fe3O4@MnO2@HKUST-1 micromotor has good prospects for future use in water treatment applications.
研究领域:
材料科学
·
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 17
·51125-51142
·
IF 5.8
Lu Mang,Wu Xue-jiao,Wan Chu-xing,Gong Qiu-ping,Li Jia-xin,Liao Shuang-shuang,Wang Yu-an,Yuan Shu-hao
A reduced graphene oxide (RGO) supported Fe 3 O 4 -MnO 2 nanocomposite (Fe 3 O 4 -MnO 2 @RGO) was successfully prepared for catalytic degradation of oxytetracycline (20 mg/L) by potassium persulfate (PS) and adsorption removal of mixture of Pb 2+ , Cu 2+ , and Cd 2+ ions (each 0.2 mM) in the synchronous scenario. The removal efficiencies of oxytetracycline, Pb 2+ , Cu 2+ , and Cd 2+ ions were observed as high as 100%, 99.9%, 99.8%, and 99.8%, respectively, under the conditions of [PS] 0 = 4 mM, pH 0 = 7.0, Fe 3 O 4 -MnO 2 @RGO dosage = 0.8 g/L, reaction time = 90 min. The ternary composite exhibited higher oxytetracycline degradation/mineralization efficiency, greater metal adsorption capacity (Cd 2+ 104.1 mg/g, Pb 2+ 206.8 mg/g, Cu 2+ 70.2 mg/g), and better PS utilization (62.6%) than its unary and binary counterparts including RGO, Fe 3 O 4 , Fe 3 O 4 @RGO, and Fe 3 O 4 -MnO 2 . More importantly, the ternary composite had good magnetic recoverability and excellent reusability. Notably, Fe, Mn, and RGO could play a synergistic role in the improvement of pollutant removal. Quenching results indicate that surface bounded SO 4 •– was the major contributor to oxytetracycline decomposition, and the -OH groups on the composite surface shouldered a significant role in PS activation. The results indicate that the magnetic Fe 3 O 4 -MnO 2 @RGO nanocomposite has a good potential for removing organic-metal co-contaminants in waterbody. Graphical Abstract
研究领域:
环境科学
·
材料科学
✓ 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）