查找使用阿拉丁产品的科研文献

Excellent fluoride removal performance by electrospun La–Mn bimetal oxide nanofibers

Shaoju Jian,Yiting Cheng,Xiaofan Ma,Hongtao Guo,Jiapeng Hu,Kaiyin Zhang,Shaohua Jiang,Weisen Yang,Gaigai Duan

La–Mn bimetal oxide nanofibers, used as an adsorbent for the defluoridation of water, were synthesized by an electrospinning and heat treatment technology. The La–Mn bimetal oxide nanofiber adsorbent with a specific surface area of 35.064 m2 g−1 displayed a good defluoridation performance. Both the adsorption kinetics and equilibrium for fluoride (F−) uptake onto La–Mn bimetal oxide nanofibers were investigated. The kinetic studies established that the adsorption attained equilibrium at about 90 min, and the PSO kinetic model was ideal for the kinetic data under 20 and 50 mg L−1. The Langmuir maximum F− uptake was computed to be 189.39 mg g−1 at 308 K and pH 3. A thermodynamic study affirmed a feasible, endothermic, spontaneous and entropy driven process of F− adsorption towards La–Mn bimetal oxide nanofibers at the studied temperature range. Except for the competitive adsorption of PO43− and F−, the presence of NO3−, CO32−, Cl− and SO42− had little effect on fluoride removal. The La–Mn bimetal oxide adsorbent exhibited a good reusability.

Linkage Isomers of 4-Methylimidazolate Mn(II) Porphyrinates: Hindered or Unhindered?

Jianping Zhao,Fei Qian,Wenping Guo,Jianfeng Li,Zeyuan Lin

Three different manganese(II) porphyrins have been exploited to react with 4-methylimidazolate (4-MeIm–), and the five-coordinate products are characterized by ultraviolet–visible, single-crystal X-ray, and electronic paramagnetic resonance spectroscopies. Interestingly, 4-MeIm– is found to bond to the metal center through either of the two N atoms (N1 or N3), which yielded two linkage isomers with either an unhindered or a hindered ligand conformation, respectively. Investigations revealed it is the large metal out-of-plane displacements (Δ24 and Δ4 ≥ 0.59 Å) that have rendered the equivalence of two isomers with a small energy difference (5.2–8.3 kJ/mol). The nonbonded intra- and intermolecular interactions thus become crucial factors in the balance of linkage isomerization. All of the products in both solution and solid states show the same characteristic resonances of high-spin Mn(II) (S = 5/2) with g⊥ ≈ 5.9 and g∥ ≈ 2.0 at 4 K, consistent with the weak effects of the axial ligand on core conformation and metal electronic configurations. Zero-field splitting parameters obtained through simulations are also reported.

L-EGCG-Mn nanoparticles as a pH-sensitive MRI contrast agent

Jiali Li,Xue Jiang,Lihuan Shang,Zhen Li,Conglian Yang,Yan Luo,Daoyu Hu,Yaqi Shen,Zhiping Zhang

This study aimed to synthesize and characterize L-epigallocatechin gallate (EGCG) complexed Mn2+ nanoparticle (L-EGCG-Mn), a proof-of-concept pH-sensitive manganese core nanoparticle (NP), and compare its magnetic resonance (MR) properties with those of Gd-DTPA, both in vitro and in vivo. Reverse microemulsion was used to obtain the L-EGCG-Mn NPs. The physicochemical properties of L-EGCG-Mn were characterized using dynamic light scattering, transmission electron microscopy, and near-infrared fluorescence small animal live imaging. The in vitro relaxivity of L-EGCG-Mn incubated with different pH buffer solutions (pH = 7.4, 6.8, 5.5) was evaluated. The T1-weighted MR imaging (MRI) properties were evaluated in vitro using hypoxic H22 cells as well as in H22 tumor-bearing mice. Cytotoxicity tests and histological analysis were performed to evaluate the safety of L-EGCG-Mn. L-EGCG-Mn showed good biocompatibility, stability, pH sensitivity, and tumor-targeting ability. Moreover, when the pH was decreased from 7.4 to 5.5, the r1 relaxivity of L-EGCG-Mn was shown to gradually increase from 1.79 to 6.43 mM−1·s−1. Furthermore, after incubation with L-EGCG-Mn for 4 h, the T1 relaxation time of hypoxic H22 cells was significantly lower than that of normoxic H22 cells (1788 ± 89 vs. 1982 ± 68 ms, p=.041). The in vivo analysis showed that after injection, L-EGCG-Mn exhibited a higher MRI signal compared to Gd-DTPA in H22 tumor-bearing mice (p < .05). Furthermore, L-EGCG-Mn was found to have a good safety profile via cytotoxicity tests and histological analysis. L-EGCG-Mn has a good safety profile and pH sensitivity and may thus serve as a potential MRI contrast agent.

Fe-Mn co-embed carbon spheres for aqueous divalent Cd removal

Jiahui Deng,Yalin Cheng,Min Liu,Biyang Tu,Shan Xue,Haisheng Tao

In this study, Fe-Mn co-embed sodium alginate carbon spheres (Fe-Mn/SA-C) were prepared as a cost-effective adsorbent for aqueous Cd(II) removal by a facile pyrolysis method. The morphology and chemical composition of Fe-Mn/SA-C were explored with various characterized techniques. The results indicate that Fe-Mn/SA-C possess porous structures and abundant oxide-based functional groups. Fe-Mn/SA-C exhibits excellent adsorption properties for aqueous Cd(II) and the adsorption process is pH-dependent. The adsorption data could fit pseudo second-order and Langmuir models well, suggesting that chemisorption is a dominant adsorption mechanism and the maximum adsorption capacity is 280.11 mg −1 . Thermodynamic analysis demonstrates that the adsorption is spontaneous and endothermic. The adsorption mechanisms of Cd(II) include the complexation of Cd(II) with oxygen-based functional groups, precipitation, and ion exchange. Finally, the granulated and magnetic Fe-Mn/SA-C is an efficient and practical adsorbent for cadmium-containing wastewater treatment.

Synthesis and optical properties of Mn-doped Ba3Al2O6 intense blue oxides

Yuqian Wang,Honghong Lei,Peng Jiang,Kunyang Cui,Lin Liu,Bin Li,Wenbin Cao

The solid solution of Ba 3 Al 2- x Mn x O 6+ y (0 ≤  x  ≤ 0.2) is successfully synthesized through solid state reaction. The colors of compounds are tuned from sky blue ( x  ≤ 0.1) to ocean blue ( x  = 0.2) with the increase of Mn content. The X-ray diffraction data shows that the major phase of all the as-synthesized samples is cubic Ba 3 Al 2 O 6 structure with the space group of P 2 1 3. The oxidation state of Mn is confirmed to be +5 by X-ray photoelectron spectroscopy analysis. UV–Vis absorption spectroscopy demonstrates that the sample's color comes from the d - d transition of Mn 5+ located in [AlO 4 ].

Mn doped MoS2/reduced graphene oxide hybrid for enhanced hydrogen evolution

Liqian Wu,Xiaobing Xu,Yuqi Zhao,Kaiyu Zhang,Yuan Sun,Tingting Wang,Yuanqi Wang,Wei Zhong,Youwei Du

The hybrid material of Mn-doped molybdenum disulfide/reduced graphene oxide (Mn-MoS 2 /rGO) is successfully fabricated through a one-pot hydrothermal method . The hybrid material, evaluated as electrochemical catalyst for the hydrogen evolution reaction (HER), exhibits improved catalytic activity and good stability for the HER in acidic medium with small overpotential (approximately 110   mV). Through analyses, it can be concluded that the improvement for electrochemical HER performance of the hybrid catalyst is ascribed not only to high conductivity mainly from reduced graphene oxide, but also to fundamental catalytic activity enhancement generated by Mn ions doping into the S-edge of MoS 2 with a portion of Mo ions replacement. These results verify the facilitation effect of Mn-doping on HER activities, and the Mn-MoS 2 /rGO hybrid prepared in this work could be employed as a promising alternative to noble metal catalysts in HER.

Hollow Mn-doped CeO2@Co3O4 catalyst for NO reduction by CO

Yuxi Meng,Shaomian Liu,Yixi Wang,Wenqing Xu,Jiajian Gao,Sansan Yu,Fabing Su,Tingyu Zhu

Selective catalytic reduction of NO using CO (CO-SCR) is a promising technology for the purification of NO in the flue gas. However, the presence of O 2 significantly inhibits the activity of the CO-SCR catalyst. Herein, we synthesize a hollow Mn-doped CeO 2 @Co 3 O 4 catalyst (Mn-CeO 2 @Co 3 O 4 ), which achieved 82% NO conversion, 100% CO conversion, and 78% N 2 selectivity under 5 vol% O 2 at 200 °C, superior to those of CeO 2 @Co 3 O 4 and Co 3 O 4 @CeO 2 catalysts. The characterization results indicate that the strong electronic interaction at the heterointerfaces between Co 3 O 4 and CeO 2 plays a crucial role in promoting selective adsorption of NO. Furthermore, the Mn doping into the Co 3 O 4 lattice of the catalyst facilitates the conversion of N 2 O intermediates, thereby enhancing the overall activity. This research provides a new strategy for the design and synthesis of CO-SCR catalysts.

Mn-Specific Recognition of Guanidine Drives Selective Inhibition of Complex I

Fei Cai,Jinrong Dong,Peng Xie,Hanlong He,Huiyi Yao,Junxian Guo,Zhibo Yan,Li Ma,Tianfeng Chen

Developing structurally well-defined targeted drugs is an effective way to enhance the chemotherapy efficacy. Herein, a target mitochondrial complex I (complex I) inhibitor was developed for the key methylation site ARG-85 in the key subunit NDUFS2. Based on the unique :NH═C– group of guanidyl and the surrounding environment of ARG-85, the macrocyclic and bulky manganese porphyrin complex [MnIII(TTPPC2–)]+ was selected to insert into the gap of NDUFS2. Experimental and computational analyses revealed that the planar π system of the TTPPC2– ligand and the rotatable benzene ring stably bind between the :NH═C– group of ARG-85 and the manganese metal center, a medium-strong Lewis acid. The Mn-specific recognition of guanidine drives the selective inhibition of complex I activity. Further, MnIII(TTPPC2–)]+ was modified into targeted nanoformulation Mn NPs. In vitro and in vivo experiments confirmed the efficient and mechanism inhibition of complex I activity, offering a novel strategy for targeted drug development.

Zn-Mn-Mg alloy with superior mechanical properties and antibacterial performance

Tang Yubo,Huang Sheng,Chen Wei-chih,A Garu,Linghu Xitao,Wa Qingde,Huang Shuai,Chen Jian

Zn-Mn alloys are particularly promising biodegradable implant materials, but they are plagued by poor mechanical performance. In this work, a Zn-Mn alloy with ultrahigh strength and excellent ductility was achieved through addition of trace Mg (0.1 wt%) and equal channel angular pressing (ECAP). Specifically, the ECAP processed Zn-0.5Mn-0.1 Mg alloy exhibits an ultimate tensile strength (UTS) of 428 MPa, which is highest ever achieved in Zn-Mn-based alloys, along with a good elongation (EL) of 39%. In addition, the alloy exhibits excellent antibacterial performance against Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ). Trace Mg addition results in the formation of Mg 2 Zn 11 and MgZn 2 nano-precipitates in the alloy, which effectively pins grain growth during dynamic recrystallization (DRX) and postpones the inverse Hall–Petch relation. Consequently, the alloy possesses quite fine grains of an average grain size (AGS) of 0.71 μm, much smaller than that of its counterpart without Mg (AGS = 2.54 μm). The ultrahigh strength of the alloy is mainly ascribed to grain boundary strengthening and precipitation strengthening. The remarkable ductility of the alloy is related to deformation twinning suppression, pyramidal < c + a > slip activation, and low dislocation density.

Effect of Mg2+/F− co-doping on electrochemical performance of LiNi0.5Mn1.5O4 for 5 V lithium-ion batteries

Aijia Wei,Wen Li,Qian Chang,Xue Bai,Rui He,Lihui Zhang,Zhenfa Liu,Yanji Wang

Mg 2+ /F − co-doped LiNi 0.5 Mn 1.5 O 4 cathode material was synthesized by a facile one-step solid-state process. The effect of Mg 2+ /F − co-doping on grain morphology, phase structure, and electrochemical properties was studied by a series of characterizations. Scanning-electron-microscopy images show that Mg 2+ /F − co-doped LiNi 0.5 Mn 1.5 O 4 (denoted LNMO-MF) particles grow larger than pure LiNi 0.5 Mn 1.5 O 4 particles. X-ray diffraction, Raman spectra , Fourier transformation infrared spectroscopy , X-ray photoelectron spectroscopy, and cyclic-voltammetry tests indicate that all samples mainly display a Fd -3m space group and more Mn 3+ ions in the LNMO-MF sample after Mg 2+ /F − co-doping, which is conducive to increasing the cationic disorder degree and enhancing the electronic conductivity of electrode material. Results show that the LNMO-MF cathode material delivers an excellent rate performance with discharge capacities of 142, 144, 140 136, 132, 124, 115, and 100 mAh g −1  at 0.2, 0.5, 1, 2, 3, 5, 7, and 10C (1C = 140 mAh g −1 ), respectively. Remarkably, LNMO-MF also shows cycling stability with a capacity retention of 86.2% at 5C after 400 cycles, which is much higher than that of pure LiNi 0.5 Mn 1.5 O 4 (67.7%). The improvement of LNMO-MF's electrochemical properties could be ascribed to the Mg 2+ /F − co-doping, delivering a more stable structure, better crystallinity , the highest Li + diffusion coefficient , and the lowest charge-transfer resistance.

Mn–CoP/NC bifunctional catalysts with nanocube structures for alkaline water decomposition

Yuying Li,Shengxiong Liao,Yiming Gao,Dai Dang,Yuying Zheng,Fashen Chen

Developing highly efficient non-precious metal bifunctional catalysts remains a critical challenge in electrolytic water splitting research. In this study, we prepared Mn-doped CoP coupled with nitrogen-doped carbon nanocube (Mn–CoP/NC) catalysts using an in situ growth, low temperature oxidation, and phosphatization strategy. Due to the excellent activity of the cobalt species and the effective protection provided by the carbon shell to the metal core, these Mn–CoP/NC catalysts exhibited outstanding hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances. At a current density of 10 mA cm2, the overpotentials were as low as 90 mV for the HER and 272 mV for the OER. Moreover, the Mn–CoP/NC‖Mn–CoP/NC cell achieved a current density of 10 mA cm−2 at just 1.66 V and remained highly stable after 36 hours of continuous operation. This study offers a new strategy for designing efficient bifunctional catalysts for overall water splitting.

Enhanced Oxidation of Xylene Using Plasma Activation of an Mn/Al2O3 Catalyst

Zuliang Wu,Weili Zhou,Zhoubin Zhu,Xiaodong Hao,Xuming Zhang