APPLIED CATALYSIS A-GENERAL
·
2009
·Vol. 358
·期 2
·173-179
·
IF 3.19
Guan Huang,Shang-Yue Liu,Yong-An Guo,Ai-Ping Wang,Jin Luo,Chun-Cai Cai
The search for a reusable material as an efficient and economic catalyst for hydrocarbon oxidation is an important field of research. In this study, we investigated the highly effective combination of support and metalloporphyrin provided by manganese tetraphenylporphyrin adsorbed onto a precursor of freshly precipitated aluminium hydroxide, followed by conversion to a manganese porphyrin/boehmite compound. This was characterized using FT-IR, UV–vis spectroscopic techniques, N 2 BET analysis, X-ray powder diffraction, transmission electron micrograph technique and thermal analysis. Aerobic oxidation of cyclohexane has been investigated using the compound as a catalyst under mild conditions and in the absence of any solvent and reductant. The results indicate that it has higher catalytic activity than manganese tetraphenylporphyrin and the corresponding chitosan-supported catalyst. In particular, the catalyst exhibits good atom economy for cyclohexane oxidation, high catalyst turnover number, and good ketone and alcohol selectivity. In particular, it has excellent reusability, with no change in original catalytic activity; a quantity of catalyst containing only 1 mg of Mn TPP can be reused 8 times under the promotion of beomite (BM). In addition, we examined the reaction conditions for the use of such nanoparticle-supported manganese tetraphenylporphyrin as a mild and environmental friendly oxidation catalyst.
研究领域:
催化化学
·
纳米材料
·
绿色化学
·
有机氧化反应
·
多相催化
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 30
·期 1
·17-25
·
IF 2.324
He Ling,Shu Yao,Li Wensheng,Liu Maocheng
Perovskite oxides have attracted significant attention as capacitor electrode materials owing to their unique physical and electronic properties. In this paper, a novel La 0.7 Sr 0.3 CoO 3-δ (LSC)@MnO 2 core–shell nanorod was synthesized by controlled electrospinning combined with hydrothermal synthesis. The LSC, as a typical perovskite-type material, with excellent stability and ion–electron double conductivity, can perfectly serve as conductive backbone. Grid-like MnO 2 nanosheets are grown on LSC to form a unique core/shell nanostructure, could effectively improve the electrochemical performance of MnO 2 . The grid-like MnO 2 nanosheets shell significantly increase the effective area over which the reaction may take place and reduce the ion/electron transmission distance, which is beneficial in that it shifts in ions and electrons, enhancing the electrochemical reaction kinetics thereof. LSC@MnO 2 core/shell nanorods demonstrated good electrochemical performance with high capacitance (570 F g −1 at 1 A g −1 ), and revealed excellent cycling stability (capacitance retention remains at 97.2% after 5000 cycles). The asymmetric supercapacitor device (LSC@MnO 2 //AC) displayed a desirable energy density of 37.6 W h kg −1 at 375 W kg −1 , and still remains at 23.3 W h kg −1 at a high power density of 7489.3 W kg −1 , indicating that the LSC@MnO 2 nanorods are an outstanding pseudo-capacitive electrode material, with significant potential for application in high-performance supercapacitors.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2023
·Vol. 58
·期 7
·3066-3077
·
IF 4.5
Liu Xiang,He Zhanglong,Li Tao,Wang Xiaodong,Zhao Chen,Liu Shan,Liu Yuling,Fan Zheqiong,He Hao
MnO 2 is a promising catalyst for oxygen reduction and metal–air batteries due to the natural abundance, low cost and nontoxicity. Improving its activity is an important challenge for its large-scale commercialization. Defect engineering and heteroatom doping are the most effective means and can be easily operated through plasma treatment at different atmospheres. In this work, defects on MnO 2 are manufactured via rapid plasma treatment at Ar atmosphere while both defects and N-doping are simultaneously fabricated at N 2 atmosphere. N–MnO 2 exhibits a greatly enhanced ORR activity with a half-wave potential of 0.84 V, a limiting current density of 6.7 mA cm −2 and the number of transferred electrons of 3.9. In neutral Mg-air battery, N–MnO 2 -based battery exhibits a max power density of 124.3 mW cm −2 at a current density of 255.4 mA cm −2 and excellent stability under different working condition. These superior performances of N–MnO 2 to Ar–MnO 2 and pristine α -MnO 2 demonstrate that the defects and N-doping by plasma treatment at N 2 atmosphere significantly enhance the oxygen reduction activity. This work reveals the relationship between microstructure and oxygen reduction reaction and supplies a new idea for the developing economical and efficient oxygen reduction reaction catalysts for metal–air batteries. Graphical
研究领域:
材料化学
·
电化学
·
能源科学
·
催化化学
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Qingtang Zhang,Qiqi Shu,Fei Lian,Chunyang Du,Pengfei Gao,Ya You
Layered transition metal oxide is considered as one of the most promising cathode materials for sodium-ion batteries due to the abundant reserves of Na, Fe, and Mn. Moreover, the trivalent Fe substitution weakens the Jahn–Teller effect and enhance the crystal structure during the de/intercalation of Na + . Herein, a series of Mn-rich P2-type Na 0.67 Fe 0.1 Mn 0.9 O 2 (NFMO-600, NFMO-700 and NFMO-800) are prepared using combustion synthesis followed by calcinating at 600, 700 and 800 °C, respectively. As confirmed by XRD and SEM , NFMO-700 owns ultrafine high-purity crystal particles with a larger layer spacing and a smaller crystal size. Owing to these unique structures, NFMO-700 exhibits excellent electrochemical performance , delivering an impressive 179 mA h g −1 at 0.2C, with a capacity retention of 84.43 % after 100 cycles at 0.5C.
研究领域:
材料科学
·
电化学
·
无机化学
·
能源存储
·
固体化学
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2024
·
IF 5.3
Jiaping Guan,Guomin Sun,Gaoyuan Yu,Yu Chen,Jiawen Wei,Xiaohui Zhu,Xiaogu Huang
Sodium-ion batteries (SIBs) have garnered significant interest due to their cost-effectiveness and operational similarities to lithium-ion batteries. Amongst the various components, the cathode plays a pivotal role in determining the energy density of these batteries. Mn-based layered oxides stand out as promising cathode materials, owing to their abundance and non-toxicity. However, these oxides tend to suffer from structural instability during high-voltage cycling, leading to a decline in capacity. In this work, we have designed Ce-doped Na 0.6 Li 0.2 Mn 0.79 Ce 0.01 O 2 cathodes through a solid-state reaction process. This innovation aims to inhibit undesirable phase transitions and enhance the electrochemical performance of the electrodes. By integrating electrochemical testing with a suite of characterization techniques, we have shown that 1 mol% Ce doping effectively suppresses the formation of birnessite and the irreversible oxygen redox reactions in the high-voltage region. Moreover, our findings indicate that the detrimental phase transitions can be significantly mitigated throughout the electrochemical cycling process, thereby bolstering structural stability. Notably, the capacity of the Ce-doping cathode after 20 cycles substantially exceeds its initial discharge specific capacity, reaching 169.3 mAh g –1 . This research introduces a strategy for stabilizing the cathode structure of P2-type Mn-based layered oxides through Ce-doping, offering valuable insights for the advancement of next-generation SIBs.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2013
·
IF 4.675
B.Z. Li,Y. Wang,L. Xue,X.P. Li,W.S. Li
A novel LiMn 0.8 Fe 0.2 PO 4 /C composite is synthesized via a sol–gel process. In this composite, acetylene black is embedded in LiMn 0.8 Fe 0.2 PO 4 . The structure and morphology of the resulting composite are characterized with XRD , SEM, TEM, and BET, and its performance as the cathode of lithium ion battery is investigated by charge–discharge test and EIS , with a comparison of the sample prepared without embedding acetylene black. It is found that the embedded composite exhibits better performance than the non-embedded sample. The former delivers a reversible capacity of 160 mAh g −1 , while the latter only 142 mAh g −1 at 0.1 C (1C = 150 mAh g −1 in the work). The embedded acetylene black not only functions as a barrier for the growing of LiMn 0.8 Fe 0.2 PO 4 particles in the preparation process, which is important for the formation of nano-particles, but also helps build a stable conductive network, thus improving the charge–discharge performance of LiMn 0.8 Fe 0.2 PO 4 .
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
Chemical Science
·
2024
·Vol. 16
·期 1
·425-429
·
IF 7.6
Ang Li,Ziqi Wang,Yunhua Xu
A novel buckled-layer K1.39Mn3O6 cathode was synthesized, featuring P2-oxygen stacking and P3-K sites. The presence of two independent manganese sites significantly influences the charge distribution and diffusion pathways of potassium ions during the charge and discharge processes, resulting in exceptional electrochemical performance. A reversible capacity of 105 mA h g−1 at 100 mA g−1 and remarkable rate capability of 70 mA h g−1 at 1 A g−1 were achieved, surpassing those of most previously reported layered transition metal oxide cathodes. The findings facilitate the development of innovative cathode materials.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2019
·
IF 3.218
Li Xiaoman,Zhu Qinglin,Guo Weimin,Lu Qinghua
Lithium-sulfur (Li-S) batteries have become a research hotspot due to their high energy density , environment friendliness and low-cost. But commercial applications are hampered by rapid capacity fading and low sulfur content. Herein, the composite of integrating manganese oxide on graphene was prepared by a facile redox reaction between potassium permanganate (KMnO 4 ) and graphene in acidic aqueous solution to solve the problems of the Li-S batteries. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis show that sulfur was uniformity coated on G/MnO 2 composite. TG indicated that the G/MnO 2 /S composites contained 76.56 wt% active sulfur. The prepared cathode of G/MnO 2 /S composites exhibited excellent rate performance and cycle stability. At a high rate of 1 C, its maximum discharge capacity reached 908 mA h g −1 and its average capacity decreasing rate was only 0.105%/cycle when running over 500 cycles. The interaction mechanism of MnO 2 with polysulfides was investigated by adsorption tests and XPS analysis. The excellent electrochemical performance might be due to a combination of adsorption or catalytic properties of MnO 2 , and the conductivity network of graphene.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
应用化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 3.7
Long Zhang,Dongsheng Yang,Lilei Miao,Chunmeng Zhang,Jiexiang Li,Jiawei Wen,Chunxia Wang,Tiantian Cao,Guoyong Huang,Shengming Xu
The nickel-rich layered cathode material LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) has high energy density , lower cost and is a promising cathode material currently under development. However, its electrochemical and structural stability is poor during cycling. Among the many modification methods, cation doping has been consistently proven to be an effective strategy for enhancing electrochemical performance . Herein, the NCM811 cathode material was modified by solid-phase reactions with Mg and Al doped. In addition, the corresponding mechanism of NCM811 cathode material-doped modification is explored by density functional theory (DFT) calculations, and we have extended this approach to other ternary cathode materials with different ratios and obtained universal laws. Combined with DFT calculations, the results show that Mg 2+ occupies the Li + site and reduces the degree of Li + /Ni 2+ mixture; Al 3+ acts as a structural support during charging and discharging to prevent structural collapse. The electrochemical properties were tested by an electrochemical workstation and the LAND system, and the results showed that the capacity retention rate increased to varying degrees from 63.66% to 69.87% and 89.05% for NCM811-Mg and NCM811-Al at room temperature after 300 cycles, respectively. This study provides a theoretical basis and design strategy for commercializing cationic-doped modification of nickel-rich cathode materials.
研究领域:
材料科学
·
电化学
·
能源存储
·
计算材料学
·
无机固体化学
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2020
·
IF 2.726
Lei Wu,Yan Liu,Dengke Zhang,Liwei Feng,Wenchao Qin
Layered LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM 622) cathode materials were synthesized through spray-drying method with different pressure treatments (0, 2, 3, 4 MPa). The results of XRD and XPS showed that the LiNi 0.6 Co 0.2 Mn 0.2 O 2 with 3 MPa treated presented lower level of cation mixing. And it also led to the increase of lithium interlayer spacing and the decrease of transition metal interlayer slab. It exhibited high specific capacity of 168 mA h g -1 at 0.5 C and 130 mA h g -1 at 10 C. After 150 cycles at 10 C, the retention also maintained above 85.1%. The sample treated with 3 MPa possessed superior lithium-ion diffusion ability and lithium ion diffusion coefficient were nearly three times than that of the untreated sample. The results illustrated that pressure-treatment was a practical approach for LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathodes to improve the electrochemical performance .
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Yuyu Liu,Wenye Deng,Xianghui Chen,Yan Xue,Xuelian Bai,Pengjun Zhao,Huimin Zhang,Aimin Chang,Yongxin Xie
The perovskite CaMn x Zr (1- x ) O 3 ( x = 0, 0.05, 0.10, 0.15) (CMZO) NTC (Negative Thermal Coefficient) thermo-sensitive ceramic were prepared by the solid phase method that can be used as high temperature thermistor materials in the range of 200–1200 °C.The XRD pattern showed that CMZO is a finite solid solution and that a second phase, CaMnO 3 , will be formed after exceeding the solid solution limit (i.e., at x = 0.1). The thermal constant B value was found to decrease from 19521 K to 9217–9535 K, with a corresponding decrease in activation energy , E a , from 1.69 eV to 0.82 eV. The Nyquist plot indicates that the grain boundary resistance determines the overall complex impedance. Moreover, the aging drift rate (ΔR/R 0 ) was found to be lower than 4.3%, which is an indication of an excellent high temperature stability of the CMZO ceramic material.
研究领域:
材料科学
·
无机非金属材料
·
热敏材料
·
高温电子器件
·
功能陶瓷
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2015
·
IF 2.288
Zhiyong Mao,Jingjing Chen,Liang Sun,Qifei Lu,Dajian Wang
(Ba,Sr) 3 MgSi 2 O 8 :Eu 2+ , Mn 2+ phosphors with 430/505/660 nm tri-bands or 430/660 nm dual-bands emission were demonstrated in this work by controlling the appearence or not of green emitting intermediate phases, (Ba,Sr) 2 SiO 4 :Eu 2+ . Through varying the stoichiometric amount of SiO 2 in precursor, the coexistence of green emitting intermediate phase tended to be sensitive and diversified. Laser Microzone Raman spectrum was employed to look insight into the lattice stretch and the preferential occupation sites of Ba 2+ ions in Sr 3 MgSi 2 O 8 lattices. The local structure and the crystal field of Eu 2+ luminescent centers were found to be disturbed by distorted arrangement of cross-linked [MgO 6 ] octahedra and [SiO 4 ] tetrahedra. This mechanism approach provided some new insights to further understanding the adjustment strategy of green emitting intermediate phases in (Ba,Sr) 3 MgSi 2 O 8 :Eu 2+ , Mn 2+ phosphor potentially applied as red/blue dual-bands emitting or red/green/blue tri-bands emitting materials.
研究领域:
材料科学
·
无机化学
·
发光材料
·
固体物理
·
光电子学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）