APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2020
·Vol. 126
·期 3
·1-9
·
IF 1.81
Ding Feng,Lin Jing,Wu Tengyan,Zhong Hongbin
Magnetic nanoparticles were one of the most promising materials for targeted magnetic hyperthermia application due to the excellent magnetic properties. In this work, the magnetic nanoferrite of Mn 0.6 Zn 0.4 La x Fe 2− x O 4 ( x = 0.09, 0.1, 0.15, 0.2, 0.25 and 0.3) was synthesized by the hydrothermal method. Various physical properties of samples have been characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscopy and vibrating sample magnetometer. XRD results revealed that the lattice constants a t and crystallite size of the Mn–Zn nanoferrites decreased with increasing La 3+ content. The characteristic absorption bands of spinel nanoferrites and polyethylene glycol were observed in the FTIR spectra. FTIR results indicated that polyethylene glycol was coated on the Mn–Zn nanoferrites successfully. The saturation magnetization ( M S ), magnetic moment ( M r ) and anisotropy constant ( K ) were affected by La 3+ ion content. The M S of Mn 0.6 Zn 0.4 La 0.09 Fe 1.91 O 4 was 58 emu/g, which could be potential hyperthermia in biomedical application.
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MATERIALS RESEARCH BULLETIN
·
2019
·
IF 3.355
Zhen Cao,Ji Li,Li Wang,Ke Xing,Xi Yuan,Jialong Zhao,Xin Gao,Haibo Li
In this work, the effects of Co 2+ ions on the structural and luminescent properties of intrinsic and Mn doped CsPbCl 3 NCs were studied by using photoluminescence (PL) spectroscopy, X-ray diffraction (XRD) spectroscopy, and transmission electron microscopy (TEM). The undoped and Mn doped CsPbCl 3 NCs with various Co/Pb molar ratios were synthesized at 190 °C. It was found that the quantum yields of purple emissions in these CsPbCl 3 NCs were greatly enhanced up to 30% after Co 2+ ions were doped. The diffraction peaks in XRD patterns shifted to a large angle with the increase of Co/Pb molar ratio, indicating Co doping in Pb-site. Further both intrinsic and Mn doped CsPbCl 3 NCs exhibited uniform cubes with average sizes of 8–10 nm and good crystallinity after Co doping. The enhancement of purple emissions from excitons in the CsPbCl 3 NCs was related to the reduction of nonradiative defects in these NCs through Co 2+ doping.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Qian Liu
Although Mn-doped lead halide perovskites could alleviate the environmental burden of Pb, their synthesis process suffers from intricate operations, high operating temperature, low production, or toxic strong polar solvents. Developing a simple and green route for Mn-doped halide perovskites with mass production is highly desirable for perovskite-derived applications. In this work, we developed a facile and environmental-benign synthesis strategy for large-scale preparation of Mn-doped lead halide perovskite nanocrystals . The nanocrystals were prepared via a mechano-synthesis process without organic solvents . We investigated the influence of atomic composition on their morphology, crystal structure and optical performance. Our results show that the perovskite nanocrystals have dual-emissions from the 4 T 1 to 6 A 1 transition of Mn 2+ and the excitonic recombination of perovskite hosts, respectively. The achieved Mn:CsPbX 3 nanocrystals show well-tailored color rendering when used as LED phosphors. This work presents a scalable and facile strategy for Mn-doped perovskite production without organic solvents, which promises low-cost and eco-friendly LEDs.
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CATALYSIS TODAY
·
2019
·
IF 4.888
Peiman Xu,Lijun Qiu,Licheng Wei,Yiyi Liu,Dingsheng Yuan,Yi Wang,Panagiotis Tsiakaras
The efficient design of highly active, economical and stable electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline electrolyte still remains a great challenge. Herein, Mn doped Ni 2 P microflowers with porous feature directly grown on Ni foam have been successfully synthesized via a facile hydrothermal method and phosphorization treatment. By detailed analyzing X-ray photoelectron spectroscopy results, it can be found that the electronic structure of Ni 2 P can be efficiently regulated by Mn doping. As expected, the Mn-doped Ni 2 P microflowers with an optimal Mn/Ni ratio of 0.053 exhibit a low overpotential of 205 mV for HER and 330 mV for OER to achieve a current density of 100 mA cm −2 in 1.0 M KOH solution. Furthermore, when this electrocatalyst is adopted as both the cathode and anode for overall water splitting, a current density of 10 mA cm -2 is achieved at a cell voltage as low as 1.58 V, accompanied with high stability.
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APPLIED CATALYSIS A-GENERAL
·
2019
·
IF 4.63
Jianan Li,Xinyong Li,Xin Wang,Libin Zeng,Xin Chen,Jincheng Mu,Guohua Chen
In this work, a spinel cobalt doped manganese oxide catalyst with the morphology of rambutan-like hollow sphere was successfully obtained by a facile carbon sphere-templated and post-calcined strategy. Multiple strategies such as visible light assistant, Jahn-Teller (J-T) effect, Co-Mn synergistic interaction, and abundant active sites exposed have been considered together in this elaborated system. Theoretical calculation was performed to simulate and analysis the catalyst crystal properties. Visible light assistant cobalt doped manganese oxides possessed a much superior performance and the CoMn1/3 sample exhibited the highest catalytic activity. Norfloxacin (NOR) degradation paths were analyzed by HPLC-MS and the visible light-PMS activation coupling mechanism on cobalt manganese oxides was finally speculated from numerous aspects. This study not only provides the multiple regulations of catalysts from the electronic states and morphology, but also demonstrates the promising potential of various coupling techniques integrated in the contaminant remediation.
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Nano Energy
·
2019
·
IF 15.548
Biwei Wang,Jinxiang Zou,Xiaochen Shen,Yuchi Yang,Guangzhi Hu,Wei Li,Zhenmeng Peng,Dustin Banham,Angang Dong,Dongyuan Zhao
Iron-nitrogen-carbon (Fe-N-C) materials featuring Fe-N 4 moieties are promising candidates to replace commercial Pt/C catalysts for the oxygen reduction reaction (ORR). Here we report a novel Mn-Fe-N/S@mC catalyst comprising atomically dispersed Fe-N 4 sites and a trace amount of Mn-N 2 S 2 sites, which are homogeneously anchored on an ordered mesoporous graphitic carbon framework. This dual-metal catalyst is realized based on the chemical conversion of self-assembled Mn 0.43 Fe 2.57 O 4 nanocrystal supracrystals, with the dual metal sites and the graphitic framework derived from nanocrystal cores and the associated capping ligands, respectively. When evaluated as electrocatalysts for the ORR, Mn-Fe-N/S@mC exhibits excellent catalytic activity in alkaline media , outperforming conventional Pt/C and most non-precious-metal catalysts reported previously. Notably, the synergistic effect of having Fe and Mn together improves the catalytic activity by a factor of ~ 5. To better understand the high efficiency of Mn doping in enhancing the activity of Fe-N 4 sites, density functional theory calculations were carried out, revealing that the synergistic interaction between the dual metal sites reduces the *OH reduction energy barrier during the oxygen reduction pathway.
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ACS Nano
·
2019
·
IF 13.903
Shuang-Shuang Wan,Qian Cheng,Xuan Zeng,Xian-Zheng Zhang
Here, a Mn(III)-sealed metal–organic framework (MOF) nanosystem based on coordination between Mn(III) and porphyrin (TCPP) via a one-pot method was designed and constructed. Mn(III), as a sealer, not only quenched TCPP-based fluorescence but also inhibited reactive oxygen species (ROS) generation, which made MOFs an “inert” theranostic nanoparticle. Interestingly, upon endocytosis by tumor cells, MOFs were disintegrated into Mn(II) and free TCPP by intracellular glutathione (GSH) in tumor cells, owing to redox reaction between Mn(III) and GSH. This disintegration would lead to consumption of antioxidant GSH and activated Mn(II)-based magnetic resonance imaging (MRI) as well as TCPP-based fluorescent imaging. More importantly, such a GSH-regulated TCPP release could implement controllable ROS generation under irradiation, which avoided side effects (inflammation and damage of normal tissues). As a consequence, after unlocking by GSH, Mn(III)-sealed MOFs could significantly improve the therapeutic efficiency of photodynamic therapy by combining controlled ROS generation and GSH depletion after precise dual tumor homing.
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PubMed
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 23
·22818-22828
·
IF 2.8
Sun Yanlong,Zheng Tong,Zhang Guangshan,Liu Bei,Wang Peng
The regeneration of adsorbent by thermal method may transfer the adsorbed organic pollutants into the air phase. Herein, manganese and cerium are loaded on adsorbent as catalyst to mineralize the adsorbed organic pollutants during regeneration. The modified adsorbent is characterized by scanning electron microscope-energy dispersive spectrometer, Brunauer Emmett Teller-Barrett Joyner Halenda, and X-ray photoelectron spectroscopy. Regeneration of modified adsorbent is evaluated by adsorbent yield and mineralization percentage of the absorbed organic pollutants. The results demonstrate that the mineralization percentage of tetracycline increased about 100% after the modification. Besides, the loaded catalyst can significantly reduce the regeneration temperature. Furthermore, cerium can reduce the adverse impact causes by manganese which will decrease the adsorption capacity of adsorbent. Kinetics, equilibrium, thermodynamic, and other adsorption properties of modified adsorbent towards tetracycline are further studied. The theoretical maximum of adsorption capacity calculated by Langmuir model is 196.4 mg g −1 , and the kinetics of adsorption fits pseudo-second-order model. The adsorption of tetracycline on the adsorbent is feasible, spontaneous, and endothermic. The properties of synthesized composite material are stable; the yield of Ce/Mn/Al 2 O 3 adsorbent can keep higher than 95% even after five adsorption/regeneration cycles. This research provides another perspective on the design and regeneration of adsorbent, which focus on reducing the secondary pollution during adsorbent regeneration process.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2015
·
IF 2.729
Xiuli Song,Tailai Yang,Haiyan Du,Wenyan Dong,Zhenhai Liang
Transition metal mixed oxides of Mn and Cr with the nominal compositional formula Mn x Cr 1 − x O 1.5 ( x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were obtained by the thermal decomposition method. The powders were analyzed by SEM (scanning electron microscopy), XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy). The electrochemical properties of the Mn x Cr 1 − x O 1.5 electrodes for the OER (oxygen evolution reaction) in alkaline solution were evaluated by LSV (linear sweep voltammetry), staircase voltammetry and chronoamperometry . The results indicated that the mixed oxides were solid solutions of Mn 2 O 3 (bixbyite) and Cr 2 O 3 (eskolaite), and when x = 0.2, the catalyst had better catalytic activity in the OER process than did that of single Mn 2 O 3 and Cr 2 O 3 . At the high potential region (1.0 V vs Ag/AgCl), the current density of the Mn 0.2 Cr 0.8 O 1.5 electrode was ~ 80 times higher than that of Mn 2 O 3 and ~ 9 times higher than Cr 2 O 3 , and its overpotential ( η = 367.3 mV at a current density of 1.0 mA·cm − 2 ) was considerably lower than that of single Mn 2 O 3 ( η = 996.5 mV) and Cr 2 O 3 ( η = 648.5 mV) catalysts and was comparable to the precious metal oxide IrO x . The stability testing indicated that the mixed oxides had good stabilities in strong alkaline solution during the OER process.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2014
·
IF 2.129
Fang fei Liu,Ying Yu,Bi xia Lin,Xiao gang Hu,Yu juan Cao,Jian zhong Wu
Daminozide (B9) is a growth inhibitor with important regulatory roles in plant growth and development. Locating and quantifying B9-binding proteins in plant tissues will assist in investigating the mechanism behind the signal transduction of B9. In this study, red fluorescent Mn-doped CdTe quantum dots (CdTeMn QDs) were synthesized by a high-temperature hydrothermal process. Since CdTeMn QDs possess a maximum fluorescence emission peak at 610 nm, their fluorescence properties are more stable than those of CdTe QDs. A B9-CdTeMn probe was synthesized by coupling B9 with CdTeMn QDs. The fluorescence intensity of the probe is double that of CdTeMn QDs; its fluorescence stability is also superior under different ambient conditions. The probe retains the biological activity of B9 and is unaffected by interference from the green fluorescent protein present in plants. Therefore, we used this probe to label B9-binding proteins selectively in root tissue sections of mung bean seedlings. These proteins were observed predominantly on the surfaces of the cell membranes of the cortex and epidermal parenchyma.
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Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 39
·20922-20931
·
IF 8.867
Jieyu Liu,Meng Yu,Xuewei Wang,Jie Wu,Changhong Wang,Lijun Zheng,Dachi Yang,Hui Liu,Yan Yao,Feng Lu,Weichao Wang
An alternative material SmMn2O5 mullite with regard to Pt/C is proposed to catalyze the oxygen reduction reaction (ORR) by combining density functional theory (DFT) calculations and experimental validations. Theoretical calculations are performed to investigate the bulk phase diagram, as well as the stability and electrocatalytic activity of the ORR under alkaline conditions for SmMn2O5 (001) surfaces, which are passivated by nitrogen atoms to avoid any spurious interference. The adsorptions of relevant ORR species (O*, OH*, OOH* and OO*) tend to compensate the coordination of manganese atoms to form Mn-centered octahedral or pyramidal crystal fields, and the corresponding binding energies fulfill a linear relationship. An oxygen molecule prefers to be reduced to OH−via a four-electron pathway and this prediction is verified by electrochemical measurements on the as-prepared SmMn2O5 catalyst with a nanorod structure. Volcano curves are obtained to describe the trends in theoretical ORR activity as a function of a single parameter, i.e. the oxygen binding energy. An overpotential of 0.43 V is obtained at the O* binding energy around 3.4 eV, which is close to the experimental observation (0.413 V) in this work. SmMn2O5 mullite exhibits favorable ORR activity and superior stability with only ∼5% decay in activity over 20 000 s of chronoamperometric operation in contrast to ∼15% decrease of Pt/C, making it a promising candidate for a cathode catalyst.
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JOURNAL OF ADVANCED OXIDATION TECHNOLOGIES
·
2016
·Vol. 19
·期 2
·358-365
·
IF 0.738
Yanfang Liu,Guixia Li,Zhili Zhang,Xiang Gao,Jianrui Niu,Junna Zhao,Zaixing Li
γ-Al 2 O 3 supported Manganese and Ferric oxide (Mn-Fe/Al 2 O 3 ) were synthesized and used as catalyst for ozonation of bisphenol A (BPA) in aqueous solution. It was conducted in a semi-batch reactor under different operational conditions, i.e., varying initial pH, ozone flow rate, initial BPA concentration and catalyst dosage. The results indicated that the presence of Mn-Fe/Al 2 O 3 lead to a great enhancement in ozonation of BPA. Using 5 g/L Mn-Fe/Al 2 O 3 evaluated BPA (50 mg/L) removal efficiency up to 84.1% under particular reaction conditions, while that of the single ozonation process was 48.5%. The influence of tert-butanol demonstrated that initiation of hydroxyl radicals was involved and plays an important role in catalytic ozonation. The decrement of solution pH in catalytic ozonation was much higher than that in ozone alone, indicating much small molecule acids produced in catalytic ozonation process. The repeated use the Mn-Fe/Al 2 O 3 proved that it had a good reusability and stability.
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