Journal of Macromolecular Science Part A-Pure and Applied Chemistry
·
2019
·
IF 1.163
Huayao Chen,Junlong Hu,Hongjun Zhou,Xinhua Zhou,Hua Xu
The triblock copolymer F127 (molecular formula (EO)106(PO)70(EO)106) was adopted as template with TMOS as the silica source. They were hydrolyzed by acidic aqueous solution in which chlorpyrifos (CH) and metal ions (Mn+) were introduced to the products to construct "F127-Mn+-CH" coordination structure in one step. Different sustained release systems were prepared through changing the composition of acidic aqueous solution added during the preparation. The characterization results confirmed the coordination interaction existing among metal ions, mesoporous silica and chlorpyrifos. It was also proved that the chlorpyrifos loaded in the sustained release system existed as amorphous state. According to SEM and TEM observation, the pore of the material presented as face-centered cage-type cubic structure with IM-3M symmetry similar to SBA-16 which is in accordance with N2 adsorption isotherms. The as-synthesized system showed significant pH sensitivity in the sustained release process indicating that the sustained release system can be well stored in neutral environment and activated while sprayed into earth in acid or basic environment. Their sustained release curves can be described by Korsmeyer-Peppas equation in neutral while accords with Higuchi under acid or basic environment.
研究领域:
材料科学
·
纳米技术
·
药物递送系统
·
环境化学
·
农药制剂
✓ 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
DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 4
·1849-1861
·
IF 3.5
Haodi Dong,Changcheng Liu,Que Huang,Yanjun Chen
Nowadays, the poor conductivity and unstable structure have become obstacles for the popularization of Na3V2(PO4)3 (NVP). In the current work, a dual-modified Mn0.1Cl0.3-NVP composite doped with Mn and Cl is prepared by a facile sol–gel method. When Mn2+ with a large ionic radius replaces small V3+, it can improve the stability of the NVP crystal structure. In addition, the replacement of V3+ by Mn2+ in a low valence state can generate redundant hole carriers, which is conducive to the rapid transport of electrons. The substitution of PO43− by Cl−, which is more electronegative, can reduce the impedance and facilitate the movement of Na+. Owing to the synergistic effect of Mn and Cl co-substitution, the structural stability of NVP was systematically enhanced, and the electron transfer and ion diffusion were effectively improved. Consequently, the optimized Mn0.1Cl0.3-NVP sample demonstrated superior electrochemical performance and kinetic properties. It exhibited a high reversible capacity of 109.2 mA h g−1 at 0.1C. Even at 15 and 30C, high discharge capacities of 70.3 mA h g−1 and 68.2 mA h g−1 were observed after 2000 cycles with capacity retention above 80%. Moreover, it delivered remarkable capacities of 77.1 and 73.4 mA h g−1 at 100 and 200C with retained capacity values of 50.3 and 47 mA h g−1, respectively, after 2000 cycles. Furthermore, the assembled Mn0.1Cl0.3-NVP//HC full cell delivered a high value of 94.7 mA h g−1 and lit LED bulbs, indicating its excellent application potential.
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
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 46
·102880-102893
·
IF 5.8
Li Yunhe,Li Hao,Zhao Baogang,Ma Yanming,Liang Peiyuan,Sun Tianjun
The escalating levels of surface ozone concentration pose detrimental effects on public health and the environment. Catalytic decomposition presents an optimal solution for surface ozone removal. Nevertheless, catalyst still encounters challenges such as poisoning and deactivation in the high humidity environment. The influence of support on catalytic ozone decomposition was examined at a gas hourly space velocity of 300 L·g −1 ·h −1 and 85% relative humidity under ambient temperature using Cu-Mn–doped oxide catalysts synthesized via a straightforward coprecipitation method. Notably, the Cu-Mn/SiO 2 catalyst exhibited remarkable performance on ozone decomposition, achieving 98% ozone conversion and stability for 10 h. Further characterization analysis indicated that the catalyst’s enhanced water resistance and activity could be attributed to factors such as an increased number of active sites, a large surface area, abundant active oxygen species, and a lower Mn oxidation state. The catalytic environment created by mixed oxides can offer a clearer understanding of their synergistic effects on catalytic ozone decomposition, providing significant insights into the development of water-resistant catalysts with superior performance. Graphical
研究领域:
环境催化
·
大气污染控制
·
材料化学
·
表面科学
·
催化化学
·
环境工程
·
功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2018
·
IF 6.945
Xiaodeng Wang,Hongpeng Zhou,Dingke Zhang,Mingyu Pi,Jiajia Feng,Shijian Chen
Developing stable and high-efficiency hydrogen generation electrocatalysts , particularly for the cathode hydrogen evolution reaction (HER), is an urgent challenge in energy conversion technologies. In this work, we have successfully synthesized Mn-doped NiP 2 nanosheets on carbon cloth (Mn-NiP 2 NSs/CC), which behaves as a higher efficient three dimensional HER electrocatalyst with better stability at all pH values than pure NiP 2 . Electrochemical tests demonstrate that the catalytic activity of NiP 2 is enhanced by Mn doping. In 0.5 M H 2 SO 4 , this Mn−NiP 2 NSs/CC catalyst drives 10 mA cm −2 at an overpotential of 69 mV, which is 20 mV smaller than pure NiP 2 . To achieve the same current density , it demands overpotentials of 97 and 107 mV in 1.0 M KOH and phosphate-buffered saline (PBS), respectively. Compared with pure NiP 2 , higher HER electrocatalytic performance for Mn−NiP 2 NSs/CC can be attributed to its lower thermo-neutral hydrogen adsorption free energy , which is supported by density functional theory calculations.
研究领域:
材料科学
·
电化学
·
能量转换
·
纳米材料
·
催化
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Wanyun Li,Bangchuan Zhao,Jin Bai,Hongyang Ma,Peiyao Wang,Yunjie Mao,Shuai Lin,Xiaoguang Zhu,Xuebin Zhu,Yuping Sun
Lithium rich manganese based materials (LMR) have promised the likeliest candidate for next generation lithium-ion battery cathodes owing to its high energy density and low materials cost. However, severe capacity decline and voltage decay hinder their practical application, which is closely concerned with the structure degradation and irreversible oxygen release. Herein, a simple strategy to reinforce the structural stability of LMR materials by constructing heterostructure with Nb-based MXenes (Nb 2 CT x / Nb 4 C 3 T x ) is proposed. A small amount of spinel phase and pseudo-bonding between Nb and O ions as well as extra oxygen vacancies can be induced by the MXenes addition in LMR, effectively inactivating the surface oxygen and suppressing the structure distortion. In addition, MXene can also alleviate the volume change during cycling process and provide additional transport channels for electrons. The ably designed 3 wt% LMR/Nb 2 CT x cathode presented high initial Coulombic efficiency of 85.6% at 0.1C (vs. 77.4% for the pristine material) and excellent cycling performance with a capacity retention of 83.8% after 200 cycles at 0.5C (vs. 66.6% for the pristine material). This work sheds some light on stabilizing the structure of lithium-rich manganese materials and provides a new idea for the design of other high performance cathode materials.
研究领域:
材料科学
·
电化学
·
储能技术
·
锂离子电池
·
纳米材料
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Huan Zhou,Wenhua Cheng,Qingcui Liu,Wei Wang,Weilu Zhang,Zhouliang Tan,Juan Ding,Yudai Huang
Li-rich Mn-based oxides (LRMO) greatly increase its output energy density due to its additional oxygen redox activity. However, the inherent oxygen loss and irreversible phase transition induce low initial coulombic efficiency and serious voltage decay, further seriously impeding its industrial application. Herein, a near-surface in-situ reconstruction strategy has been proposed, which constructs the oxygen vacancies and spinel phase coating on the surface of single-crystal Li-rich Mn-based oxide (SC-LRMO) concurrently to improve Li + storage performance via the oxalic acid induction method. Intensive exploration based on structure characterizations demonstrates that such a near-surface in-situ reconstruction strategy not only accelerates the transmission of Li + , but also stabilizes high-voltage redox reactions by trapping the escaping O n− within the newly formed spinel phase coating. Impressively, the modified sample exhibit 91.1% capacity retention ratio after 300 cycles, superior to the SC-LRMO (74.5% capacity retention ratio after 300 cycles). Additionally, even at a high cut-off voltage of 5 V, the acid etched sample exhibits significantly enhanced cycling stability, delivering 200 mAh g −1 with a 94% capacity retention ratio after 300 cycles. This surface self-reconstruction strategy provides profound insights into regulating the surface structure of LRMO for high-energy-density lithium-ion batteries.
研究领域:
材料科学
·
电化学
·
储能
·
电池技术
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Yin Xie,Yongcheng Jin,Lan Xiang
The nontoxicity and low cost make LiMn2O4 a competitive cathode material for lithium-ion batteries. LiMn2O4 has a high theoretical capacity (296 mAh g–1) when cycled in the 3 and 4 V regions. However, it displays a low practical capacity (∼120 mAh g–1) because of the unavailability of the 3 V region caused by severe Jahn–Teller distortion. The present work investigated the full utilization of LiMn2O4 in both 3 and 4 V by tuning the nanoscale interfacial properties. Li-rich structures at the surface and interface of the spinel material and nanograin strain were introduced to improve the performances and were achieved by grinding LiMn2O4 and Li2O at 700 rpm for 10 h under an argon atmosphere. The product shows a high initial discharge capacity of 287.9 mAh g–1 at 0.05 C between 1.2 and 4.6 V and retains 83.2% of the capacity after 50 cycles. The nanoscale interfacial structure was clarified by spherical aberration-corrected microscopy and XRD refinement, and complex occupancies of Li and Mn were found at the interface. A correlation between the interfacial properties and electrochemical performance was established, and the improved performance could be attributed to the polycrystalline nature of the material, the unique Li-rich interfacial structure, and the slightly elevated valence state of Mn. The present results may provide insight for further evaluating the complex mechanism of controlling the electrochemical performance of LiMn2O4.
研究领域:
材料科学
·
电化学
·
储能
·
锂离子电池
·
纳米材料
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Fuping Song,Juping Zhang,Dongfang Li,Tao Zhu,Xing Zhu,Hua Wang
Oxidative dehydrogenation (ODH) of ethylbenzene is a promising process for styrene production. However, its application is limited by product overoxidation and purification requirements due to the co-feeding of mild oxidants. Herein, we report a facile manganese-based catalyst (K/Mn 3 O 4 -Al 2 O 3 ) and achieve competitive styrene selectivity of 88 % and ethylbenzene conversion of 95 % at 450 ℃ (84 % yield vs. ∼ 60 % yield in commercial dehydrogenation process at 600 ℃) under a cyclic redox ODH scheme. The introduction of Al 2 O 3 into MnO x restructures composite oxides and depresses bulk lattice-oxygen migration for the partial oxidation of ethylbenzene. The surface modification using potassium creates reactive sites and regulates surface properties, achieving ethylbenzene activation and high conversions. Highly active lattice oxygen in catalysts after bulk and surface modifications selectively converts ethylbenzene to styrene and water. This study provides an understanding of roles of manganese-based catalysts in styrene generation and offers a strategy to modulate lattice oxygen on catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Linna Dai,Xin Zhou,Yuan Yang,Pei Hu,Lijie Ci
Nonaqueous Li − O 2 battery (LOB) is considered one of the most promising energy storage system due to its ultrahigh theoretical specific capacity (3500 Wh kg −1 ). Introducing vacancies in CoMn 2 O 4 catalysts is regarded as an effective strategy to enhance the electrochemical performances of LOB. However, the relation between vacancy types in CoMn 2 O 4 and catalytic performances in the LOB remains ambiguous. Herein, ordered porous CoMn 2 O 4 with oxygen and metal vacancies is obtained via solvothermal reaction followed by temperature-controlled calcination using polystyrene spheres as templates. The increase in treatment temperature reduces the content of oxygen vacancies while increasing that of the metal vacancies. Notably, experimental results and theoretical calculations show that oxygen vacancies in CoMn 2 O 4 have a greater influence than metal vacancies in modulating the LiO 2 adsorption during the reaction processes and reducing the overpotential. CoMn 2 O 4 synthesized at 500 ℃ (CoMnO-500) with higher oxygen vacancies exhibits stronger adsorption onto the LiO 2 , facilitating the formation of film-like Li 2 O 2 . Therefore, an LOB with the CoMnO-500 catalyst presents the lowest overpotential of 1.2 V and longest cycle lifespan of 286 cycles at a current density of 200 mA g −1 . This study offers insights into the effect of CoMn 2 O 4 vacancies on the formation pathway of Li 2 O 2 discharge products.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2017
·Vol. 4
·期 8
·085028
·
IF 1.068
Guangguang Huang,Chunlei Wang,Shuhong Xu,Yiping Cui
For ultrasmall Mn-doped quantum dots (QDs), the energy transfer of the exciton to the Mn is the key factor for Mn emission. Herein, the Ag-induced electron trap state energy level, which is an intermediate energy level between the conduction band (CB) and 4T1 of Mn, is proposed for improving the energy transfer. After doping the Ag and forming Ag&Mn:ZnInS QDs, most excitons will first be captured by the intermediate energy level and then be transferred to Mn d-states, leading to enhanced photoluminescence (PL) quantum yields (QY) of the QDs from the original 17% (Mn:ZnInS QDs) to 30% (Ag&Mn:ZnInS QDs).
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Yu Zhou,Molin Sun,Meilan Cao,Yijin Zeng,Mingru Su,Aichun Dou,Xiaochuan Hou,Yunjian Liu
Layered sodium iron manganese oxide cathodes have attracted great interest owing to their high specific capacity and cost-effective metal resources, while the detrimental phase transitions and surface structural degradation severely limit their commercial applications. In this work, the bulk and surface structure stability of a P 2-Na 0.67 Fe 0.5 Mn 0.5 O 2 cathode can be synergically enhanced by a one-step Li/Nb co-doping strategy. Structural characterizations reveal that Li doping promotes the formation of P 2/O3 biphasic structure and makes the unfavorable P 2-OP4 phase transition convert into a smooth solid-solution reaction. Nb doping enhances the mobility of sodium ions and forms strong Nb-O bonds, thereby enhancing the stability of the TMO 2 layer structure. In particular, the Nb element induces the surface reorganization of an atomic-scale NaNbO 3 coating layer, which could effectively prevent the dissolution of metals and surface side reactions. The synergistic mechanism of enhanced electrochemical performance is proved by multiple characterizations during cycling. As a result, the as-prepared Na 0.67 Li 0.1 Fe 0.5 Mn 0.38 Nb 0.02 O 2 exhibits improved capacity retention of 85.4 % than raw material (45.7 %) after 100 cycles at 0.5C (1C = 174 mA g −1 ) within 2.0–4.0 V. This co-regulating strategy provides a promising approach to designing highly stable sodium-ion battery cathodes. Furthermore, a full cell of Na 0.67 Li 0.1 Fe 0.5 Mn 0.38 Nb 0.02 O 2 with hard carbon displays excellent cycling stability (85.1 % capacity retention after 100 cycles), making its commercial operation possible. This synergistic strategy of biphasic structure and surface reorganization is a critical route to accelerate the application of layer oxide cathodes.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）