JOURNAL OF HAZARDOUS MATERIALS
·
2018
·
IF 6.434
Yulin Huang,Xike Tian,Yulun Nie,Chao Yang,Yanxin Wang
Cu(II) doped mesoporous MnO 2 (Cu-MnO 2 ) was prepared to establish an intimate functional link between the structure substitution and catalytic peroxymonosulfate (PMS) activation. Based on the characterization of powder X-ray diffraction (XRD), N 2 adsorption-desorption measurement, scanning electron microscope (FE-SEM) and transmission electron microscope (TEM), Cu-MnO 2 had a typical long range ordered mesoporous structure and Cu was successfully introduced in octahedral framework. It exhibited excellent catalytic activity and stability for the phenol degradation by PMS. Phenol was always efficiently degraded over Cu-MnO 2 at a pH range of 3.5–9.0. For example, the reaction rate constant at pH 7.0 was 0.073 min −1 , which was two times higher than that of MnO 2 (0.039 min −1 ). Importantly, 1 O 2 was identified as the primary reactive species in Cu-MnO 2 /PMS system. X-ray photoelectron spectroscopy (XPS) confirmed that more exposed surface oxygen defects due to Cu doping were responsible to the enhancement of PMS activation for phenol degradation. The results of PMS decomposition and oxygen evolution indicated that surface oxygen defects lower the reaction energy barrier of PMS decomposition by generating 1 O 2 via the energy trapping by oxygen. Finally, the heterogeneous PMS activation mechanism over Cu-MnO 2 was proposed.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2015
·Vol. 119
·期 4
·1483-1490
·
IF 1.704
Wang Xiaoxia,Yu Jianhua,Dong Hongzhou,Yu Mingxun,Zhang Baoqin,Wang Wen,Dong Lifeng
In this work, metal oxide (MnO 2 , SnO 2 and Co 3 O 4 )–graphene composite materials were successfully prepared via different synthesis methods. Uniform metal oxide nanoparticles were well dispersed on graphene sheets, and transmission electron microscopy characterizations showed that the average sizes of MnO 2 , SnO 2 , and Co 3 O 4 particles were about 60, 5, and 10 nm, respectively. Reflection losses of graphene composites and pure graphene were systematically evaluated between 2 and 18 GHz, which revealed that all composites exhibited enhanced microwave absorption properties compared to pure graphene. The minimum reflection losses of MnO 2 -graphene, SnO 2 –graphene, and Co 3 O 4 –graphene composites with a thickness of 2.0 mm were −20.9, −15.28, and −7.3 dB at the frequency of 14.8, 15.94, and 9.6 GHz, respectively, whereas −4.5 dB for pure graphene. The enhanced absorption ability probably originated from the combined advantage of metal oxide particles and graphene, which proved beneficial to improve the impedance matching of permittivity and permeability. Besides, the intrinsic characteristics of MnO 2 , SnO 2 , and Co 3 O 4 nanoparticles, the interface between nanostructured metal oxides and graphene sheets, and the multi-dielectric relaxation processes are all influence factors to improve the properties of microwave absorption.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
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
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Yuhui Xu,Gaini Zhang,Xiaoxue Wang,Xiangyang Li,Jianhua Zhang,Xinyue Wu,Yitong Yuan,Yukun Xi,Xuan Yang,Ming Li,Xiaohua Pu,Guiqiang Cao,Zihao Yang,Bo Sun,Jingjing Wang,Huijuan Yang,Wenbin Li,Jiujun Zhang,Xifei Li
Birnessite-type MnO 2 (δ-MnO 2 ) exhibits great potential as a cathode material for aqueous zinc-ion batteries (AZIBs). However, the structural instability and sluggish reaction kinetics restrict its further application. Herein, a unique protons intercalation strategy was utilized to simultaneously modify the interlayer environment and transition metal layers of δ-MnO 2 . The intercalated protons directly form strong O H bonds with the adjacent oxygens, while the increased H 2 O molecules also establish a hydrogen bond network (O H···O) between H 2 O molecules or bond with adjacent oxygens. Based on the Grotthuss mechanism, these bondings ultimately enhance the stability of layered structures and facilitate the rapid diffusion of protons. Moreover, the introduction of protons induces numerous oxygen vacancies , reduces steric hindrance , and accelerates ion transport kinetics. Consequently, the protons intercalated δ-MnO 2 (H-MnO 2-x ) demonstrates exceptional specific capacity of 401.7 mAh/g at 0.1 A/g and a fast-charging performance over 1000 cycles. Density functional theory analysis confirms the improved electronic conductivity and reduced diffusion energy barrier. Most importantly, electrochemical quartz crystal microbalance tests combining with ex-situ characterizations verify the inhibitory effect of the interlayer proton environment on basic zinc sulfate formation. Protons intercalation behavior provides a promising avenue for the development of MnO 2 as well as other cathodes in AZIBs.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ULTRASONICS SONOCHEMISTRY
·
2016
·
IF 4.556
Ling-Xia Zuo,Li-Ping Jiang,E.S. Abdel-Halim,Jun-Jie Zhu
Porous MnO 2 as a non-noble metal oxygen reduction reaction (ORR) electrocatalyst was prepared by a simple sonochemical route. The as-prepared porous MnO 2 exhibited higher electrocatalytic activity , superior stability and better methanol tolerance than commercial Pt/C catalyst in alkaline media. Furthermore, the ORR proceeded via a nearly four-electron pathway. Cyclic voltammetry (CV) and rotating-disk electrode (RDE) measurements verified that the ORR enhancement was attributed to the porous structure and good dispersity, which facilitated sufficient transport of ions, electrons, O 2 and other reactants in the process of ORR. The results indicated that a facile and feasible sonochemical route could be used to prepare highly active porous MnO 2 electrocatalyst for ORR, which might be promising for direct methanol fuel cells.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
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
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Aerzigu Xukeer,Jin Li
ZnO/MnO 2 nanostructures, including nanosheets and nanotubes, were synthesized by hydrothermal and annealing method. The carefully designed ZnO/MnO 2 heterostructure significantly enhances ammonia gas sensing performance at room temperature (RT). By integrating heterojunction formation with structural optimization, this approach facilitates faster charge carrier transport and increases the surface area compared to pure ZnO. The incorporation of nanosheet- and nanotube-structured ZnO/MnO 2 heterojunctions leads to a substantial reduction in response/recovery time, which decrease to 6 s and 3 s, accordingly. Furthermore, first-principles calculations are employed to elucidate the potential sensing mechanism by analyzing the electronic density of states, electrostatic potential, charge transfer, population analysis, and adsorption energy between the sensing materials and ammonia molecules.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Yuebei Yang,Yaozhong Wang,Chao Xue,Yujung Lin,Jyh-Fu Lee,Xiaoyun Yi,Zhi Dang
The clean-up of acid mine drainage (AMD) is challenging, as classical treatment including a pH neutralization step produces large amounts of toxic sludge . Here we demonstrated that removal of heavy metals through adsorption at low pH was achievable with the use of ε-MnO 2 adsorbent, which could be produced in a simple one-step process. The material, which was negatively charged even at pH 2, exhibited outstanding potential for the removal of heavy metals at strongly acidic pH. At pH 2, adsorption capacities were achieved of 172.14 mg/g towards Pb 2+ (at an initial concentration of 400 mg/L), 65.64 mg/g for Fe 3+ (at 300 mg/L) and 8.5 mg/g for Cd 2+ (at 10 mg/L). Mechanistic studies revealed that ion exchange was the main adsorption mechanism for removal of Pb 2+ , while electrostatic interaction was dominant for Fe 3+ and Cd 2+ removal. In the case of Pb 2+ adsorption, double corner sharing (DCS) complexes were formed at the edges, which promoted the dissolution of structural Mn(III), thereby generating Mn 2+ and vacancies which promoted Pb 2+ adsorption via an ion exchange process. In the case of Fe 3+ and Cd 2+ adsorption, along with electrostatic adsorption, triangle corner sharing (TCS) dominated complex formation at the intermediate vacancies, and less Mn 2+ was released. Note that the Mn 2+ was in dynamic equilibrium with structural Mn(Ⅲ) and Mn(Ⅳ). The actual AMD was retreated in 5 cycles by ε-MnO 2 , the removal rates of 100% were achieved for Pb 2+ , Fe (total) and Mn 2+ , together with 98% for Cu 2+ and 95.1% for Cd 2+ , all of which reached the national emission standards. This approach is a highly suitable option for AMD treatment that avoids toxic sludge formation.
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
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Yong Qian,Chenling Huang,Rong Chen,Shizhen Dai,Chunyan Wang
A composite of well dispersed MnO 2 nanoparticles adhered on multi-walled carbon nanotubes (MnO 2 @MWNT) is obtained through facile hydrothermal process and followed by high temperature annealing. The nanoscale MnO 2 particles were homogeneously distributed on the surface of MWNTs under polyvinyl pyrrolidone (PVP)-assisted reaction. The MnO 2 @MWNT composite (34.43 wt. % MnO 2 ) displays a high specific capacitance of 285.12 F/g at a current density of 1 A/g in 1 M Na 2 SO 4 electrolyte. The electrode exhibits good cycling stability, which the specific capacitance retention retains up to 90.17% after 1000 cycles at 1 A/g.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
DOI
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
·
材料科学
·
能源存储
·
无机化学
·
纳米材料
✓ 已验证
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Li Huang,Shangying Qin,Yuanjin Xu,Shiqi Cheng,Jin Yang,Yilin Wang
MnO 2 nanosheets (MnO 2 NSs) were prepared and used as both oxidant of 3, 3′, 5, 5′- tetramethylbenzidine (TMB) and recognizer of UA, a simple colorimetric approach for sensitive detection of uric acid (UA) was established. In the medium of weak acid, MnO 2 NSs exhibited strong oxidation capacity and could oxidize colorless TMB to generate a blue oxidation product (oxTMB) with an absorbance signal. However, the introduction of UA could inhibit MnO 2 NSs - mediated TMB oxidation and reduce the formation of oxTMB, resulting in the blue fading and the absorbance weakening. Under the conditions of incubation time 20 min, pH 3.0, TMB 0.5 mM, and MnO 2 NSs 50 μM, the decrease in absorbance was linearly dependent on UA concentration in the range of 0.5–30.0 μM with a detection limit of 0.21 μM. Furthermore, the approach has been applied for determining UA in human urine samples with recoveries between 93.1 and 102.4 % and relative standard deviation less than 3.0 %.
研究领域:
分析化学
·
生物医学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2019
·Vol. 11
·期 27
·13058-13068
·
IF 6.97
Jiapei Gu,Xiangqian Li,Zhan Zhou,Wanqiang Liu,Kai Li,Jinwei Gao,Ying Zhao,Qianming Wang
A natural resource such as peony flower has been employed for the first time as a new carbon precursor to prepare green-emitting carbon nanodots (CDs). The emission peak is situated at 523 nm and the excitation wavelength can be extended to the visible light range (452 nm). Due to the formation of CD–MnO2 nanocomposites, the emission intensity of CDs is sharply reduced as a consequence of Förster resonance energy transfer (FRET). Moreover, glucose can be recognized due to the enzymatic conversion of glucose by glucose oxidase to generate H2O2. The MnO2 nanosheets are reduced to form Mn(II) ions, and the fluorescence of CDs can be recovered. The fluorescence intensity has been improved linearly based on the increasing concentration of glucose (0.5–250 μM) with a detection limit as low as 0.18 μM. This strategy gives a new selection of eco-friendly precursors in carbon nanomaterials and such a consecutive recognition process provides valuable insights for bio-analysis.
研究领域:
材料科学
·
生物分析
·
化学
✓ 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）