SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Wenjing Zong,Zhaoming Guo,Minghuo Wu,Xianliang Yi,Hao Zhou,Siyuan Jing,Jingjing Zhan,Lifen Liu,Yang Liu
Endocrine-disrupting chemicals (EDCs) cause serious threats to human health. Five types of MnO 2 were synthesized and characterized. They exhibited different removal performances for three EDCs, i.e., estrone (E1), ethynylestradiol (EE2) and bisphenol A (BPA). Only δ-MnO 2 can completely remove E1 within 120 min at pH 3.0. Free Mn (III) was determined at the beginning of the reaction and participated in the EDCs removal process. Electron spin resonance (ESR) indicated that δ-MnO 2 could produce superoxide anions (·O 2 − ) and singlet oxygen ( 1 O 2 ) in the existence of methanol. The reactive oxygen species (ROS) quenching experiments showed 1 O 2 have certain contribution to the E1 removal by δ-MnO 2 . The source of ROS is mainly the lattice oxygen from δ-MnO 2 , and can be replenished through the layer structure destruction caused by the reaction between Mn(III) and E1. The ROS dependent EDCs removal by δ-MnO 2 leads to a deep understanding on this well-known oxidant.
研究领域:
环境科学
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化学工程
·
水处理
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DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2025
·
IF 5.6
Hanrui Zhao,Minfeng Chen,Xinxin Mi,Wei Li,Weiwei Qian,Qinghua Tian,Jizhang Chen
Aqueous zinc-ion batteries (AZIBs) have emerged as a promising technology in the realm of large-scale energy storage, with cathode material performance being a critical determinant of their practical viability. Among various cathode material candidates, MnO 2 has garnered substantial attention, whereas it suffers from poor cyclability and sluggish reaction kinetics. Herein, an efficient approach is presented to address these challenges through the development of a phytic acid-modified δ-MnO 2 , fabricated through a one-step oil-bath strategy. In the composite, the phytic acid coating can mitigate MnO 2 dissolution, and the insertion of phytic acid with excellent zincophilicity can promote Zn 2+ ion intercalation and diffusion, hence significantly improving electrochemical kinetics and reversibility. Owing to these advantages, the modified MnO 2 offers a large specific capacity of 233.4 mAh g –1 at 0.2 A g –1 , and maintains 83.6 % and 48.2 % of that capacity as the current density rises to 1 and 5 A g –1 , respectively. Under a large mass loading of 10 mg cm –2 , this material exhibits outstanding cycling stability, retaining 90.4 % of its initial capacity after 1000 cycles. This work provides valuable insights into material engineering for advanced battery technologies.
研究领域:
储能技术
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材料科学
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电化学
·
纳米技术
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产品关联
DOI
高影响因子
Catalysts
·
2023
·Vol. 13
·期 3
·490
·
IF 3.9
Wenrui Zhang,Meilu Hao,Yonghui Wang,Pengfei Sun,Dongjuan Zeng,Xinya Wang,Peng Liang
Layered δ-MnO2catalysts were prepared using the one-step redox method in precursor solutions with five different pH values (pH = 7, 9, 11, 13, and 14). The effects of pH on the physical properties and catalytic activity of the catalyst were investigated through XRD, SEM, TEM, BET, XPS, H2-TPR, and HCHO degradation tests at room temperature. The results showed that the layer spacing, manganese vacancy content, Mn4+/Mn3+ratio, and surface-reactive oxygen species content of MnO2increased with the increase in pH value in the alkaline range. When the catalyst was prepared at pH = 13, the above characteristics of the catalyst reached the optimal value which contributed to the high catalytic activity. Combined with the related characterization results, it was proved that changing the pH can affect the degree of oxidation in the catalyst synthesis process, increase the number of active oxygen and the oxygen mobility of the catalyst, and effectively improve the catalytic activity of the manganese dioxide catalyst for HCHO. This work represents a giant step toward the preparation of an effective catalyst for practical applications of HCHO removal at room temperature at a low concentration and high velocity.Keywords:δ-MnO2;pH;formaldehyde;manganese vacancy;surface-reactive oxygen species
研究领域:
催化
·
环境科学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Ruimei Fang,Qiuyu Feng,Haibao Huang,Jian Ji,Miao He,Yujie Zhan,Biyuan Liu,Dennis Y.C. Leung
δ -MnO 2 was prepared via a facile in-situ redox reaction and used for catalytic oxidation of HCHO, a major indoor air pollutant. The washing treatment during catalyst preparation could impose great effect on content of K + and catalytic activity. δ -MnO 2 catalyst without washing treatment contains the highest content of K + ion and exhibits the best catalytic activity among various δ -MnO 2 samples. The HCHO removal efficiency keeps at 100% for first 600 min. The δ -MnO 2 samples were characterized by advanced technologies including XRD, Raman, XPS, TPR, TPD and in-situ DRIFTS. The XPS results indicates that K + ions increases the AOS value of Mn and the ratio of surface-adsorbed oxygen over δ -MnO 2 . The content of K + ions improves the amount and redox ability of surface mobile oxygen species, enhancing catalytic oxidation of HCHO.
研究领域:
环境科学
·
催化材料
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DOI
高影响因子
WATER RESEARCH
·
2022
·
IF 13.4
Junwen Ding,Jinlong Wang,Xinsheng Luo,Daliang Xu,Yatao Liu,Peijie Li,Shirong Li,Rui Wu,Xinlei Gao,Heng Liang
Membrane-based technology has been confirmed as an effective way to treat emulsified oily wastewater, however, membrane fouling is still one of practical challenges in long-term operation. Herein, a novel passive-active combined strategy was proposed to control membrane fouling in continuous oily wastewater purification, where the δ-MnO 2 decoration layer helped to reduce the total fouling ratio (passive strategy for fouling mitigation) and the catalytic cleaning effectively removed the irreversible oil fouling (active strategy for fouling removal). The functional membrane was prepared via in-situ modification, referred to as δ-MnO 2 @TA-PES. The morphology, crystalline phase, chemical structure and surface properties of the membranes were systematically characterized. Compared with PES, the δ-MnO 2 @TA-PES possessed superhydrophilicity, enhanced electronegativity and narrowed pore size. The δ-MnO 2 @TA-PES achieved high water permeation flux of 723.9 L· m − 2 · h − 1 ·bar −1 , excellent oil rejection with separation efficiency above 98.5% for various emulsions, and durable anti-oil-fouling performance with FRR b of 98.0%. Notably, the oil cake layer fouling on δ-MnO 2 @TA-PES was greatly alleviated owing to its enhanced surface properties. In addition, δ-MnO 2 @TA-PES showed high cleaning efficiency in the peroxymonosulfate (PMS) cleaning process, where the radical and nonradical pathways occurred simultaneously. And the active substances generated in the nonradical process (especially 1 O 2 ) were considered as the main contributor to the reduction of irreversible fouling. Overall, the novel strategy of fouling control ensured the efficient operation of ultrafiltration membranes for the continuous oily wastewater purification.
研究领域:
环境工程
·
材料科学
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产品关联
DOI
PubMed
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2025
·
IF 3.5
Yang Luyao,Zou Xuehua,Wang Hanlin,Chen Tianhu,Liu Haibo,Sun Fuwei,Chen Dong
Birnessite-type (δ-MnO 2 ) exhibits a high adsorption and catalytic performance to remove organic contaminants, but it still suffers from agglomerates, low specific surface area, and uneven distribution of active sites. Here, a novel birnessite-loaded biochar (δ-MnO 2 @BC, MBC) was prepared by chemical precipitation and used for the catalytic degradation of tetracycline under visible light. The biochar provides a large number of birnessite loading sites, which increases the specific surface area of the material, and reduces the electron–hole pair complexation rate. Photocatalytic results showed that under optimal conditions, 91.89% of TC could be degraded by 20% MBC(m(δ-MnO 2 )/m(BC) = 20%) at a pH value of 3.0, with a negligible effect by solid–liquid ratio and temperature. Our evidences demonstrate that photogenerated electrons and holes serve as the key active species, whereas superoxide radicals play a supplementary role. The MBC photocatalyst exhibits excellent stability, maintaining an 85% TC removal efficiency after five recycling cycles. In addition, the proposed degradation pathways of TC were presented, suggesting a partial mineralization by visible light photocatalysis using MBC. This study provides new ideas for the treatment of antibiotic wastewater with manganese oxides and biochar materials. Graphical abstract
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 15
·9675-9684
·
IF 12.732
Fei Li,Yi-Lin Liu,Gui-Gen Wang,Dong Yan,Gui-Zhong Li,Hai-Xu Zhao,Hua-Yu Zhang,Hui-Ying Yang
With the increased development of wearable electronics, flexible zinc ion batteries (ZIBs) have attracted widespread attention owing to their low cost, superior safety, and simple fabrication process. Nevertheless, the limited active mass loading and low specific capacity remain challenges to be overcome. Herein, an effective in situ growth strategy is used to boost the mass loading and specific capacity of flexible ZIBs. We employed a mussel-derived polydopamine layer as an inductive catalyst to prompt the growth of flower-like δ-MnO2 on carbon cloth, which demonstrated strong adhesion to the surface, high mass loading, and excellent flexibility. In addition, the formed 3D conductive and supporting networks contribute to the realization of superior long cycle life, as well as a high specific capacity. As a result, the as-obtained flexible cathode can achieve a high initial discharge capacity of 1.3 mA h cm−2 at a current density of 1 mA cm−2 and a reversible capacity of 0.25 mA h cm−2 at 10 mA cm−2 for 10 000 cycles. Moreover, its reaction mechanism in ZIBs was analyzed via a series of ex situ characterization techniques, and the results suggest that the charge–discharge behavior is determined based on the Zn2+ (de-)intercalation in the δ-MnO2 interlayer. Remarkably, the as-developed flexible cathode is assembled into a flexible quasi-solid-state device, which shows excellent flexibility and can easily power one LED-based device, which has significant application prospects in wearable electronics. This work provides a novel tactic for the design of flexible batteries with high active mass loading and excellent electrochemical performance via employing polydopamine as an inductive catalyst.
研究领域:
材料科学
·
能源存储技术
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DOI
高影响因子
ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Ce Qiu,Xiaohui Zhu,Liang Xue,Mingzhu Ni,Yang Zhao,Bo Liu,Hui Xia
Adding Mn 2+ in aqueous electrolyte is a well adopted approach to improve cycle performance for Zn/MnO 2 batteries. The function of Mn 2+ additive in aqueous electrolyte, however, is not well understood, which could affect revealing the real performance of the MnO 2 cathode itself. In this work, a battery system with Zn anode and birnessite MnO 2 cathode is constructed and systematically investigated by using MnSO 4 additive in the electrolyte with different concentrations. The function of Mn 2+ in the electrolyte, the structural evolution of the electrode, the reaction mechanism, and the cause for capacity fading are comprehensively investigated in this system. It is found that Mn 2+ can be continuously electro-oxidized at the cathode and form ε-MnO 2 when the charge voltage is above 1.7 V during cycling, leading to successive capacity increase up to hundreds of cycles. The capacity increase, however, stops after certain cycle numbers, and is followed by fast capacity fading, which is correlated to the competition between ε-MnO 2 formation and phase transition from birnessite to spinel ZnMn 2 O 4 . It is suggested that addition of Mn 2+ in the electrolyte cannot stabilize the MnO 2 cathode and the improved cycle performance is achieved at the expense of consuming the Mn 2+ in the electrolyte.
研究领域:
电化学
·
材料科学
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DOI
高影响因子
WATER RESEARCH
·
2026
·
IF 12.8
Yue Wang,Jingyi Lin,Yonghuan Zhao,Weiguang Lv,Bo Liang,Peihua Li,Kaisheng Zhang,Xing-jiu Huang
Tetracycline (TC) is widely detected in natural waters, yet its transformation under environmentally relevant oxidative conditions remains poorly understood, because most previous studies have focused on engineered oxidation systems employing strong oxidants or external energy input. Here we show that humic-like phenolic moieties can act as active mediators to redirect δ-MnO 2 -driven TC transformation from slow direct oxidation to a phenoxy-radical-mediated coupling pathway. Screening of 18 humic-acid model compounds identified acetosyringone (AS) and syringaldehyde (SyrA) as the most effective co-reactants, increasing the apparent rate constants ( k obs ) of TC by about 8.5- and 5.9-fold, respectively. Analyses indicate that TC transformation is governed by syringyl-type phenoxy radicals generated via surface-mediated one-electron transfer on δ-MnO 2 , with reactivity controlled by the fraction of deprotonated phenolic precursors (ArO − ) over a near-neutral pH range. The structure-activity analysis further revealed that ortho‑methoxy and para-carbonyl functionalities favor radical stability and cross-reactivity, whereas para-carboxyl substitution biases the mediator toward self-coupling and unproductive oxidant consumption. These substituent-dependent trends provide molecular-level insight into how humic-like phenolics regulate TC transformation at Mn oxide interfaces.
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产品关联
DOI
PubMed
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Jun Hua,Xianwen Wu,Fangxi Xie,Mingmei Wu
Manganese-based aqueous zinc-ion batteries are considered to be one of the most promising candidates owing to its abundant resources, environmental friendliness and high safety. However, some severe problems associated with cathode are mainly plagued by Mn (III) disproportionation and Jahn-Teller distortion, leading to undesired manganese dissolution and reduced their cycle life. Herein, Cr-doped δ-MnO 2 is synthesized by a simple hydrothermal method. This study demonstrates how Cr-doping addresses these challenges by narrowing the lattice spacing between MnO 2 layers, promoting self-confinement, and mitigating Mn 2+ dissolution. As a result, Cr-doped δ-MnO 2 exhibits enhanced crystal structure stability, with superior capacity retention of 65.80 % compared to 51.53 % for pristine δ-MnO 2 after 300 cycles at 500 mA/g. Our findings provide an alternative avenue for mitigating Mn dissolution, laying the groundwork for the adoption of Zn/MnO 2 batteries.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2026
·
IF 4.4
Tao Xiudan,Yang Xiaohan,Li Fufen,He Yuqing,Liu Chenhui,Dan Nianhua,Li Zhengjun
It remains challenging to prepare δ -MnO 2 catalyst with high catalytic performance by facile and low-energy green synthesis method. In this work, an ultrasonic-assisted method using plant-derived green reducing agents (quercetin, apigenin, and glucose) was employed to prepare δ -MnO 2 catalysts at room temperature. Due to the type and quantity of hydroxyl groups (phenolic or glycosyl), and the ultrasonic treatment time, the crystallinity and surface lattice defects, specific surface area, and surface Mn 3 + concentration are modulated, thereby effectively regulating the oxygen vacancies of the δ -MnO 2 samples. The results showed that the δ -MnO 2 -Q30 catalyst prepared with quercetin containing the highest number of phenolic hydroxyl groups exhibited outstanding catalytic activity and stability. Specifically, under static test conditions at room temperature, the removal efficiency of HCHO reached 96% within 30 min for approximately 1 ppm HCHO, and remained at 92% after five cycles. This indicates that the increase in the number of phenolic hydroxyl groups, along with appropriate reaction time, can improve the oxygen vacancies in the δ -MnO 2 structure, promote the activation of surface-adsorbed oxygen species, accelerate the generation of ROS, and thus facilitating the oxidative degradation of HCHO. Furthermore, EPR and in situ DRIFTS were employed to systematically detect ROS and reaction intermediates, elucidating that oxygen vacancy-induced ROS are the key factor for the conversion and oxidation of intermediates. This work provides new insights for further developing green synthetic δ -MnO 2 particles and enhancing their catalytic performance for formaldehyde removal at room temperature. Graphical
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DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Kun Li,Yongxin Liang,Jingfeng Wu,Xu Guo,Guiting Wang,Zhi Zhang,Chenfeng Guo
Cost-effective manganese dioxide (MnO 2 ) promises the economical advantage of rechargeable aqueous zinc-ion batteries (ZIBs) but suffers its low electrical conductivity, the irreversibility of structural transformations during electrochemical reactions, and the slow kinetics of the reactions. This study employs a one-step co-precipitation technique to synthesize Cu 2+ intercalated δ-MnO 2 nanoflower. The intercalation of Cu 2+ not only enlarges the interlayer spacing through the interaction with water molecules, but also strengthens the interlayer structure with Cu 2+ as the pillars, improves the ionic conductivity, and enhances the rate capability of δ-MnO 2 . It is attributed to the co-insertion/extraction mechanism of Zn 2+ /H + . Therefore, the Cu 2+ intercalation δ-MnO 2 developed for ZIBs demonstrates a high specific capacity (300 mAh g −1 at 0.1 A g −1 ), long cycling stability (179 mAh g −1 until 2000 cycles at 1 A g −1 89.9 % capacity retention), and superior rate capability (195 mAh g −1 at 1 A g −1 ). Meanwhile, the flexible ZIBs assembled with this cathode material have wider commercial applicability.
研究领域:
材料科学
·
电化学
✓ 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）