MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 4
·1-9
·
IF 5.479
Tong Yao,Liu Xueyan,Zhang Lei
Magnetic porous microspheres composed of Fe 3 C, MnO and graphitic carbon (Fe 3 C/MnO/GC) were prepared by a one-pot method. A polycondensate obtained from urea and formaldehyde served as the carbon source and was calcined in the presence of metallic iron and manganese to yield Fe 3 C/MnO/GC. The resultant hybrid has highly mesoporous architecture, large specific surface, graphitic structure and adequate saturation magnetism. It is shown to possess excellent pre-concentration ability for herbicides (monuron, chlortoluron, atrazine and terbutylhylazine). The sorbent can be easily separated and has a long service lifetime (>25 cycles). Under optimized conditions, the sorbent excels by good recoveries (78–120%), high enrichment factors (45–50) and good precision (RSDs ≤10.7%). The limits of detection are 0.01–0.10 μg L −1 for (spiked) water samples, 0.22–0.87 μg kg −1 for grape samples, and 0.18–0.74 μg kg −1 for potato samples. This work offers a new strategy for the construction of magnetic bimetallic heterostructured GC hybrids.
Schematic presentation of magnetic porous Fe 3 C/MnO/graphitic carbon microspheres and their application for the enrichment of trace level herbicides prior to HPLC analysis.
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PubMed
高影响因子
Carbon Letters
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2025
·
IF 5.8
Hu Chaoshuai,Liu Yuanxin,Zhang Jian,Zhu Yaming,Yin Xitao,Zhao Xuefei
Using durian shell as a carbon source and triethanolamine as a nitrogen dopant, nitrogen-doped carbon dots (N-CDs) were prepared via the hydrothermal method. First, by exploring different reaction times, reaction temperatures, and carbon source/dopant ratios to synthesize nitrogen-doped carbon dots, it is concluded that the best process conditions are 200 ℃, reaction time being 15h, and the dopant addition amount being 2mL. Structure and characteristics of the synthesized CDs were analyzed using X-ray photoelectron spectroscopy, Fourier-transform infrared, fluorescence (FL), ultraviolet–visible absorption, and Raman spectra. The N-CDs showed blue FL with a quantum efficiency of 4.28%. The FL characteristics of the N-CDs were utilized for ion detection, which demonstrated that \({\text{MnO}}_{4}^{ - }\) and \({\text{Cr}}_{{2}} {\text{O}}_{7}^{2 - }\) ions caused distinct FL quenching through static quenching, while other ions had no significant quenching effect. The detection limits for \({\text{MnO}}_{4}^{ - }\) and \({\text{Cr}}_{{2}} {\text{O}}_{7}^{2 - }\) were 37.5 and 46.2 nM, respectively. The N-CDs were subsequently employed to detect these ions in actual water samples, producing satisfactory results. Therefore, the preparation of N-CDs using durian shell as raw material and its application in practical detection work have good application feedback, which not only provides a new way for the reuse of fruit and vegetable wastes but also provides a new detection means for environmental monitoring pollutants.
研究领域:
环境科学
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材料科学
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Rong Su,Zeyi Wang,Feng Xiao,Luyao Zhang,Qihang He,Lei Wang,Yu Jiang,Lichuan Chen,Lu Yang,Ping He
Peroxymonosulfate (PMS) activation by synergy of electrochemistry and catalyst has emerged as a promising technique for the degradation of organic contaminants. Herein, manganese oxide-carbon modified graphite felt (MnO-C/GF) electrodes are successfully synthesized by pyrolyzing Mn-MOF/GF composite. MnO-C/GF is employed as an anode to remove tetracycline (TC) in a process of PMS activation with the assistance of electrochemistry (EC). Under optimal conditions (50 mg/L TC, 10 mA·cm −2 , pH 7, 0.80 mM PMS,0.05 M Na 2 SO 4 , 25 °C), MnO-C 800 /GF electrode (pyrolysis at 800 °C) achieves remarkable degradation efficiency of 90.48 % for TC after 60 min in EC-PMS system. The reaction rate constant ( k ) of MnO-C 800 /GF increases by 4.54 and 2.38 times compared to bare GF and MnO/GF in EC-PMS system, respectively. In addition, quenching test and electron paramagnetic resonance test reveal that ·OH, SO 4 − , O 2 − and 1 O 2 are involved in the degradation process at MnO-C 800 /GF-EC-PMS system. According to the results of density functional theory and liquid chromatography-mass spectrometry, the degradation of TC mainly includes hydrogenation, demethylation, deamidation, dehydroxylation and ring-opening reactions. This work demonstrates that the combination of electrochemistry and metal oxide-activated PMS is a highly efficient approach for the degradation of antibiotic contaminant.
研究领域:
环境科学
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材料科学
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高影响因子
SYNTHETIC METALS
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2017
·
IF 2.435
Binghu Wang,Saihu Pan,Yong Qin,Wensheng Tan,Yongxin Tao,Kaijian Li,Yong Kong
We report the facile synthesis of N-doped carbon-graphene-manganese oxide (N/C-G-MnO) that can serve as precious metal-free electrocatalysts for oxygen reduction reaction (ORR). The N/C-G-MnO is synthesized via polymerization of m -phenylenediamine adsorbed on graphene using KMnO 4 as the oxidant, followed by pyrolyzation of the resulting N- and MnO 2 -containing poly( m -phenylenediamine). That is, poly( m -phenylenediamine) plays multi-roles in the synthesis of the ORR catalysts: (i) Serving as interlayer spacer to prevent graphene sheets from restacking during the thermal annealing, (ii) Function as the source of N-doped carbon (N/C) and MnO for the simultaneous doping of graphene. The N/C-G-MnO exhibits better ORR activity, long-term stability and methanol tolerance than those of the commercial Pt (5%)/C catalyst.
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高影响因子
GREEN CHEMISTRY
·
2024
·Vol. 26
·期 4
·2011-2020
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IF 9.3
Lixia Wang,Xinran Hu,Huatong Li,Zhiyang Huang,Jia Huang,Tayirjan Taylor Isimjan,Xiulin Yang
Deliberate engineering of built-in electric fields (BEFs) can facilitate electron transfer and promote asymmetrical charge distribution, thereby regulating the adsorption/desorption of reaction intermediates. Herein, an oxygen-deficiency-rich MnO-CeO2 is synthetized supported on a carbon sphere (MnO-CeO2@Cs), adeptly crafted with a prominent work function difference (ΔΦ) and robust BEF, targeting the electrocatalytic oxygen reduction reaction (ORR). Empirical and theoretical results substantiate that the BEF triggers interfacial charge redistribution, fine-tuning the adsorption energy of oxygen intermediates and hastening reaction kinetics. Consequently, the MnO-CeO2@Cs showcases commendable performance (E1/2 = 0.80 V and jL = 5.5 mA cm−2), outshining its single-component counterparts. Impressively, the MnO-CeO2@Cs-based zinc–air batteries (ZABs) boast an exemplary power density of 202.7 mW cm−2 and enduring stability of 297 h. Additionally, the solid-state ZAB commands a peak power density of 67.4 mW cm−2, underscoring its potential in flexible ZAB applications. This work delineates a strategic avenue to harness interfacial charge redistribution, aiming to enhance the catalytic performance and longevity of energy conversion/storage apparatuses.
研究领域:
材料科学
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电化学
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能源存储与转换
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2018
·
IF 3.779
Xiaoshi Lang,Fang Ge,Kedi Cai,Lan Li,Qiushi Wang,Qingguo Zhang
In this paper, a novel Mn 3 O 4 /MnO nano spherical transition metal compound as bi-functional catalyst for air electrode of lithium-oxygen battery is prepared by vacuum direct current arc method. Through physical property characterization , it shows that the Mn 3 O 4 /MnO particle size can be controlled between 40 and 60 nm and evenly distributed inside the carbon material. In addition, photoluminescence test result indicates that this material has better electronic conductivity and catalytic activity than traditional MnO 2 catalyst owing to some defects in the crystal structure. The cyclic voltammetry results display that the oxidation and reduction reactions are both very obvious even at high scanning rate, although only one kind of catalyst is employed in the air electrode. This proves that the Mn 3 O 4 /MnO nano spherical transition metal compound can be as a bi-functional catalytic material. Electrochemical impedance spectroscopy also displays that the charge transfer resistance of Mn 3 O 4 /MnO catalyst is smaller and the ion diffusion speed is faster. Through charge and discharge test, it can be concluded that the voltage platform of the lithium-oxygen battery with Mn 3 O 4 /MnO as bi-functional catalyst is flat and the discharge voltage can reach 2.7 V. The specific energy can reach 7102 Wh·kg −1 at 0.025 mA cm −2 current density and a capacity limit of 1000 mAh·g −1 , it can carry out the 31 non capacity decay charge and discharge cycles.
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高影响因子
Journal of Materials Chemistry A
·
2013
·Vol. 2
·期 4
·1150-1158
·
IF 0
Bin Hua,Meng Li,Bo Chi,Li Jian
Two types of anode were prepared for a comparative study of their electrochemical performance and carbon deposition resistance. The first one was the Ni–YSZ cermet anode; and the other, designated as the Ni–MnO/Ni–YSZ, was the Ni–YSZ anode plus an on-cell reforming layer of Ni–MnO in situ reduced from MnNi2O4 with a microstructure of fine Ni particles embedded in MnO matrix. With the Ni–MnO layer on the top surface, open circuit polarization resistance of the Ni–YSZ anode decreased approximately by 1/2 in H2-3 mol% H2O and by more than 1/3 in CH4-3 mol% H2O at temperatures ranging from 650 to 800 °C. Carbon fibers were observed in the Ni–YSZ anode, rather than in the Ni–MnO/Ni–YSZ anode, after initial impedance measurements in CH4-3 mol% H2O for 1 h. The polarization resistance of both anodes at 800 °C increased with time up to 6 h in CH4-3 mol% H2O due to carbon deposition; however, the carbon formed in the Ni–MnO/Ni–YSZ anode had a lower degree of graphitization. In the atmosphere of CH4-20 mol% H2O, carbon deposition was completely depressed in the Ni–MnO/Ni–YSZ anode at 800 °C and 200 mA cm−2, which ensured a higher and more stable electrochemical performance than that of the Ni–YSZ anode.
研究领域:
材料科学
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电化学
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能源工程
·
催化
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DOI
Small
·
2024
·
IF 13
Yuejun Jiang,Cong Xu,Yunshi Li,Hong Wang,Lu Liu,Yicheng Ye,Junbin Gao,Hao Tian,Fei Peng,Yingfeng Tu,Yingjia Li
Developing multifunctional, stimuli-responsive nanomedicine is intriguing because it has the potential to effectively treat cancer. Yet, poor tumor penetration of nanodrugs results in limited antitumor efficacy. Herein, an oxygen-driven silicon-based nanomotor (Si-motor) loaded with MnO and CaO 2 nanoparticles is developed, which can move in tumor microenvironment (TME) by the cascade reaction of CaO 2 and MnO. Under acidic TME, CaO 2 reacts with acid to release Ca 2+ to induce mitochondrial damage and simultaneously produces O 2 and H 2 O 2 , when the loaded MnO exerts Fenton-like activity to produce ·OH and O 2 based on the produced H 2 O 2 . The generated O 2 drives Si-motor forward, thus endowing active delivery capability of the formed motors in TME. Meanwhile, MnO with glutathione (GSH) depletion ability further prevents reactive oxygen species (ROS) from being destroyed. Such TME actuated Si-motor with enhanced cellular uptake and deep penetration provides amplification of synergistic oxidative stresscaused by intracellular Ca 2 + overloading, GSH depletion induced by Mn 2+ , and Mn 2+ mediated chemodynamic treatment (CDT), leading to excellent tumor cell death. The created nanomotor may offer an effective platform for active synergistic cancer treatment.
研究领域:
纳米技术
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癌症治疗
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生物医学工程
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药学
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 12.5
Wenhao Xi,Xia Chen,Tongchen Wu,Jun Pan,Changrong Xia,Zhaopeng Qi,Bizhou Lin
N doped hollow carbon polyhedron with abundant meso- and macropores was in situ constructed. • The metal anchoring effect led to N doped hollow carbon supported MnO/CoMn 2 O 4 heterojunction nanoparticles. • MnO/CoMn 2 O 4 @HNC exhibits an excellent bifunctional activities with a Δ E = 0.711 V. • The battery has a peak power density of 168.6 mW cm −2 and a capacity of 788 mAh g −1 . Because of the sluggish kinetics of oxygen reduction/evolution reaction (ORR/OER) occurring at the air cathode, it is critical to develop efficient and sustainable bifunctional oxygen electrocatalysts for enhancing the real performance of Zn-air batteries (ZABs). Herein, we report a facile strategy to prepare MnO/CoMn 2 O 4 heterojunction nanoparticles embedded in N-doped hollow carbon polyhedron (MnO/CoMn 2 O 4 @HNC) through the metal anchoring effect. On the one hand, abundant meso- and macropores of the obtained MnO/CoMn 2 O 4 @HNC provide transport channels for oxygen molecules and reaction intermediates in the electrocatalytic process. On the other hand, density functional theory (DFT) calculations disclose that the interface coupling between MnO and CoMn 2 O 4 can facilitate electron transfer, and efficaciously reduce the energy barriers of rate determining steps (RDS) for ORR and OER. Owing to the advantages of structure and composition, MnO/CoMn 2 O 4 @HNC displays excellent electrocatalytic activity with a half-wave potential ( E 1/2 ) of 0.85 V for ORR and a potential of 1.561 V at 10 mA cm −2 for OER. The homemade ZABs driven by MnO/CoMn 2 O 4 @HNC perform a high power density of 168.6 mW cm −2 and a superb cycling stability (600 cycles). This work affords a promising route for in situ construction of non-precious metal bifunctional electrocatalysts with a novel structure toward ZABs. Download: Download high-res image (186KB) Download: Download full-size image
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Haiyan Wang,Zhuo Zhang,Ye Li,Feifei Zhang,Kuo Yang,Bing Xue
A clay-based quasi-solid-state electrolyte was prepared using dimethyl sulfoxide (DMSO) intercalated kaolinite as the raw material to suppress the adverse effects of free water molecules on aqueous zinc-ion batteries (AZIBs). Based on the inherent water absorption and retention properties of clay kaolinite, as well as the interlayer modification, this clay-based quasi-solid-state electrolyte not only achieved a low water content but also exhibited a strong water binding effect, which restricted the HER and side reactions involving water participation. Furthermore, the intercalation of DMSO increased the number of negative charges on the surface of kaolinite, resulting in the formation of a continuous spatial electrostatic field area around the kaolinite particles, which played a role in cation selectivity. The ionic transference number of the quasi-solid-state electrolyte reached 0.91. Additionally, the intercalation of DMSO broadened the interlayer ionic transport channels of kaolinite, further enhancing the transport efficiency of Zn 2+ in the quasi-solid-state electrolyte, achieving uniform deposition of Zn 2+ on the surface of the Zn anode, and suppressing dendrite growth to maintain a stable quasi-solid-state electrolyte/Zn anode interface. Zn||MnO 2 battery assembled with this electrolyte demonstrated a discharge specific capacity of 301 mAh/g at a current density of 60 mA g −1 . The Zn||MnO 2 battery could be stably cycled for 1000 cycles at a current density of 150 mA g −1 , and after 1000 cycles, the battery still maintained a discharge specific capacity of 248.2 mAh/g with a capacity retention rate of 84.8 %, showing excellent capacity performance and cycle stability. The Zn||MnO 2 pouch battery could still provide stable power under heavy pressure, bending, and continuous tapping and had the potential for use in flexible batteries.
研究领域:
材料科学
·
电化学
·
储能技术
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高影响因子
APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Jiacheng Xu,Tiantian Zhang,Yan Sun,Shiyu Fang,Zuliang Wu,Jiali Zhu,Lianxin Dai,Weihua Liu,Buhe Zhang,Junwei Zhang,Shuiliang Yao,Erhao Gao,Jing Li
MnO 2 is a promising catalyst due to its abundant metal valence and good redox ability. Different crystal phases of MnO 2 have different oxygen species, but the relationship between their catalytic activity and crystal structures is unclear. In this study, four MnO 2 catalysts with crystal structures ( α -, β -, γ -, and δ -MnO 2 ) were selected to unveil the roles of terminal-type (Mn O), superoxide-type Mn(-O-) 2 Mn, and bridge-type (Mn-O-Mn) oxygen species in CO oxidation . γ -MnO 2 has the best CO oxidation performance. Density functional theory calculation results show that Mn O on γ- MnO 2 can adsorb CO easier than other two types of oxygen species. Operando TPR-DRIFTS-MS results show that Mn O on the surface of γ- MnO 2 can react with CO to form terminal-type oxygen vacancies (M 2+ =□ 2– ) at low temperatures. Meanwhiles, Mn(-□-)(-O-)Mn and Mn-□-Mn can dissociate O 2 to form Mn O under certain conditions to promote CO oxidation. MnO 2 catalysts with more Mn O oxygen species are of great significance for CO oxidation at a low temperature.
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高影响因子
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