ELECTROCHIMICA ACTA
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2019
·
IF 5.383
Shouji Huang,Liwen Yang,Ming Gao,Qi Zhang,Guobao Xu,Xiong Liu,Juexian Cao,Xiaolin Wei
MnO is one of the most attractive anode materials for Li ion batteries (LIBs) due to its high theoretical capacity and low voltage hysteresis. However, its inherent low conductivity and large volume expansion hinder real application. Herein, we construct a flexible freestanding film of MnO quantum dots , N-doped carbon layer and carbon nanotubes by an effective method and demonstrate its direct application as an anode for LIBs. The microstructure observations reveal that well-dispersed MnO quantum dots with the average of 2–5 nm attach tightly on highly conductive carbon nanotube substrates and covered by N-doped carbon layers. Such unique nanocomposite structure provides effective carbon protective layers to accommodate volume change, ensure almost the whole surface of each MnO quantum dots to attend electrochemical reaction , and increases electron conductivity and reduces Li + diffusion distance. Furthermore, kinetic analysis and characterization tests indicate that capacitive contribution for Li storage in the freestanding film is calculated to be high and further oxidation of Mn 2+ to higher valence state upon cycling generates lots of specific capacity, thus endowing it with excellent rate, ultrahigh capacity and outstanding cycling stability. The flexible freestanding anode delivers ultrahigh capacity of 1741mAh g −1 after 120 cycles at 0.1 A g −1 , a high-rate capability of 858 mAh g −1 at 3.2 A g −1 after 120 cycles at 0.1 A g −1 , and long-term cycling stability with a capacity of 136.5% at 1.0 A g −1 after 1000 cycles. The unique nanostructure design is believed to have great potential in general synthesis of the composite consisted of CNT and oxide quantum dots for energy storage.
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高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Ran Zhang,Xinyu Gao,Kaiyuan Zhang,Donghong Duan,Xianxian Zhou,Junwen Wang,Shibin Liu
In order to realize efficient hydrogen production with low energy consumption, the urea oxidation reaction (UOR) is the most practical alternative counter-reactions to the hydrogen evolution reaction (HER) in the overall electrochemical water splitting process. It’s highly desirable through the development of suitable cost-effective and non-precious catalysts, to design brilliant bifunctional electrocatalysts for the UOR and HER with both fast electron. Herein, the electrodeposition technique was used for synthesizing the hierarchical MnP/MnO@NiP on nickel foam (NF) and its electrocatalytic behavior was explored for HER and UOR. For delivering the 10 mA·cm −2 current density, the Co-MnP/MnO@NiP/NF electrode needed only 36.2 mV overpotential in HER and 1.24 V in UOR. During overall urea electrolysis, the cell voltage in 10 mA·cm −2 was only 1.52 V, which is 300 mV lower than the HER-OER process. The remarkable catalytic performance for HER and UOR can be attributed to the protective role of MnO x and the interfacial electron interactions within the material, which significantly boosted its overall activity, and the introduction of Co could enhance the electrochemical interface to obtain highly dispersed samples. The introduction of Ni could form a NiOOH with good catalytic activity intermediates with good catalytic activity to facilitate the UOR process.
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高影响因子
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
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.
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高影响因子
Carbon Letters
·
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.
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高影响因子
SYNTHETIC METALS
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2017
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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.
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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
·
电化学
·
能源工程
·
催化
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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
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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