ELECTROCHIMICA ACTA
·
2022
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IF 7.336
Tao Xu,Fanghui Du,Ling Wu,Zhongxu Fan,Lina Shen,Junwei Zheng
The urgent demands of developing Co-free materials for lithium ion batteries with high energy density for next generation electric vehicles have driven the attention of researches to LiNiO 2 stabilized by doping of common elements. Among those elements, manganese is usually used to stabilize cathode material crystal structures to achieve better electrochemical performances. However, the Li + /Ni 2+ cation disorder causing by Mn doping is greatly neglected of the effect on electrochemical behaviors. In order to elucidate the exact effect of Mn-doping, herein, we synthesize Mn-doped LiNiO 2 with extra low Mn content by using the solid-state element thermal interdiffusion strategy. Under calcination at high temperature, with the spherical species coated with Mn-containing gel as the precursor, Mn can be evenly doped into the framework of LiNiO 2 material. It is demonstrated that the small amount of Mn-doping can greatly stabilize both the crystal structure of LiNiO 2 and integrity of the secondary particles during the electrochemical cycling to provide the excellent electrochemical cycling performance and thermal stability of the materials. Nevertheless, the rate capability of the materials is strongly dependent on the amount of the doped Mn, due to the Li + /Ni 2+ cation mixing formed in the synthesis process and introduced in the electrochemical cycling. In the presence of a tiny quantity of the doped Mn, the enlarged crystal lattice would be favorable to the diffusion of the Li + ions in the crystal. However, serious Li + /Ni 2+ cation mixing of the materials with high content of the Mn-doping deteriorates the rate performance of the materials. Thus, in this case, the Mn content is optimized to be 4 mol%, endowing the material with an initial capacity of 202 mAh g −1 at 0.1 C, and a capacity retention of 85.41% after 200 cycles at 0.5 C. For the Mn-doped LiNiO 2 materials, it is suggested that to control the Li + /Ni 2+ cation mixing would be crucial for gaining the materials with superior electrochemical performance.
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Catalysis Science & Technology
·
2022
·Vol. 12
·期 10
·3137-3147
·
IF 6.177
Zhong-Ting Hu,Zi-Yan Jin,Si-Yan Gong,Xiuzhen Wei,Jia Zhao,Mian Hu,Jun Zhao,Zhong Chen,Zhiyan Pan,Xiaonian Li
Spinel ferrites with magnetic properties have great potential for the decontamination of aqueous systems due to their ease of recycling by magnetic separation. Herein, the purpose is to enhance ZnFe2O4 spinel properties in terms of magnetization and catalytic performance via Mn substitution into the crystal structure. Zn1−xMnxFe2O4 (x = 0–1) nanoclusters were successfully synthesized via an optimal hydrothermal process, in which additives (i.e., citric acid and ammonia) play key roles in inhibiting impurity phase formation via homogenizing the distribution of metal ions and slowing down the reaction rate. At a Zn/Mn ratio of 1 : 3, the nanocluster Zn0.25Mn0.75Fe2O4 (ZMF0.75) composed of nanoparticles with sizes ranging from 5 to 10 nm shows the highest saturation magnetization (Ms = 68 emu g−1, which is ∼5 times greater than that of ZnFe2O4) and the best catalytic performance, with >99% azoxystrobin (AZX) degradation in a Fenton-like system. Moreover, the findings unveiled that the balance of Zn and Fe occupation in the polyhedron centres in the spinel crystal is broken upon replacing Zn with Mn. In all probability, the Zn/Fe/Mn cross-occupation phenomenon is essential for enhancing the activity of Fe and Mn multivalent metal atoms. A plausible mechanism for the synergistic effect of multiple active sites in ZMF0.75 on the formation of HO˙ and HO2˙ radicals is proposed. This work proves that Mn-substituted ZnFe2O4 could be an efficient heterogeneous Fenton-like catalyst for EOC decontamination in aqueous systems with ease for recycling via magnetic separation.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2022
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IF 9.221
Kun Yu,Guangyao Zhang,Huining Chai,Lijun Qu,Dan Shan,Xueji Zhang
Metal−organic frameworks (MOFs) have emerged as promising materials for smart sensing and imaging applications. Here, a novel micron-biscuit Mn(III)-based porphyrinic MOF is synthesized with the modulation of 4,4′-biphenyldicarboxylic acid (BPDC). The anisotropic growth of MOF is induced by the increased steric hindrance , yielding micron-biscuit Mn-TCPP(BPDC) MOF crystals. Mn(III), as a sealer, quenched the intrinsic fluorescence of porphyrin because of the ligand-to-metal charge transfer (LMCT) effect, and this disappeared fluorescence can be regularly restored and enhanced due to LMCT effect inhibition and release of free porphyrin derived from the water-induced two-stage ligand exchange (TSLE) between BPDC, porphyrin and water. The as-prepared MOF acts as an excellent “signal-on” luminescent water-sensing probe with low amount (2.5 μg/mL) that can efficiently realize the trace detection of water in various organic media with high sensitivity, especially in dimethyl sulfoxide (DMSO), the detection limit is as low as 0.04% (v/v). Moreover, Mn-TCPP(BPDC) was successfully used for sensing water content in real commercial samples. This MOF with the guest-induced TSLE not only provides inspiration for the design of new luminescent materials, but also widens the path for smart sensing.
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ACS Applied Nano Materials
·
2022
·
IF 6.14
Xiaoshuo Zhang,Ziyi Zhang,Youyu Cao,Wenzhi Tang,Zhonghong Li
Excessive sulfite (SO32–) causes serious human health problems, making its detection highly valuable. In this work, a colorimetric sensor was presented for the detection of SO32– on the basis of Co–Mn mixed metal oxide (CoMn MMO) nanorods. CoMn MMOs composed of CoMn2O4 were uniformly dispersed among Co3O4 by calcining Co6(CO3)2(OH)8·H2O@CoMn2O4 nanorods in air, which had intrinsic oxidase-like activity. The synergistic introduction of CoMn2O4 promoted electron transfer in Co3O4, which not only prevented the aggregation problem but also increased the active sites, and the catalytic activity of the resulting CoMn MMO nanoenzyme was significantly enhanced. The obtained nanocomposites could catalyze the oxidation of the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxTMB with a quite low Michaelis–Menten constant (Km) of 0.042 mM and a quick Vmax of 0.85 × 10–8 M s–1 by generating a superoxide radical (·O2–). Based on the inhibitory effect of SO32– on the CoMn MMOs-TMB system, the proposed method allowed for SO32– detection with the linear concentration range from 1.56 to 15.58 μM and a limit of detection of 62.38 nM under optimal conditions. Combined with a smartphone chromaticity analysis app, we designed a portable and disposable agarose hydrogel test kit using the proposed system, which realized the on-site semiquantitative and visual detection of SO32– in food samples.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Hanxu Lu,Zhe Hu,Hong Liu,Zizhao Fu,Hanqing Dai,Wanlu Zhang,Ruiqian Guo
Transition-metal-ion-doped quantum dots (QDs) are promising candidates to fabricate full-spectrum white-light-emitting diodes (WLEDs). In this work, a series of efficient white-light-emitting Cu,Mn-codoped ZnGaS/ZnS (Cu,Mn:ZnGaS/ZnS) QDs were synthesized by controlling the Zn/Ga molar ratio and the amounts of Mn dopants. After ZnS shelling, the photoluminescence quantum yield reached 58% and the spectrum almost covered the whole visible spectrum. Further, the stepwise doping process was investigated, which had considerable reference value to subsequent research. The Cu,Mn:ZnGaS/ZnS QDs were employed to fabricate WLEDs displaying a color rendering index of 94 and CIE coordinates of (0.34, 0.35).
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HYDROMETALLURGY
·
2021
·
IF 4.156
Luri Bao,Jingze Zhang,Jie Wu,Guotai Zhang,Yang Yang,Weiping Tang,Mei Xue
Owing to the increasing global demand for lithium, extraction of lithium from salt lake brine water has received considerable attention. In this study, the magnesium doping to produce Li 1.6 Mg x Mn 1.6-x O 4 (LMMO) was designed to overcome the limitation caused by the loss of Mn due to dissolution. The chemical and morphological properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The XRD results confirmed that the crystal structure of Li 1.6 Mn 1.6 O 4 was retained after Mg-doping. Scanning electron microscopy and energy-dispersive X-ray spectroscopy showed that LMMO has a flake-shaped structure and the Mg 2+ ions were uniformly distributed in the precursor. The doping of Mg 2+ led to the decrease of Mn 3+ content in the precursor, improving its structural stability. The adsorption capacity of LMMO-6% was 35.6 mg g −1 , which was greater than that of the undoped sample (33.2 mg g −1 ). After the tenth cycle, the dissolution loss of Mn in LMMO-6% was 0.55%, and it is smaller than that for lithium manganese oxide (0.94%). Results confirm that the structural stability was improved compared to undoped adsorbents. Moreover, batch adsorption experiments demonstrated the potential of the HMMO-6% adsorbent to be used for lithium adsorption from real salt lake brine.
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Journal of Water Process Engineering
·
2023
·
IF 7
Longxiang Xia,Jing Shen,Dengfeng Wu
Herein, Al 2 O 3 supported ultra-small Mn-CeOx nanoparticles (Mn-CeOx/Al 2 O 3 ) are prepared by a facile impregnation method for removal of phenolic compounds via catalytic ozonation . Mn and Ce species are in the form of polyvalent oxide nanoparticles with an average size of 0.9 nm. The removal efficiency of total organic carbon for phenol-containing model wastewater by Mn-CeOx/Al 2 O 3 shows a volcano relationship by changing the mass ratio of Mn and Ce, and reaches up to the peak value when the mass ratio is 5:5. The cycle stability tests suggest the removal efficiency of Mn-CeOx/Al 2 O 3 could maintain at 90.16 % after 5 circles. The enhanced performance should be attributed to the optimized magnetism and accelerated charge transfer by composition regulation. The magnetic strength changing affects the adsorption mode of O 3 , while the redox cycle of Mn(IV)/Mn(III) and Ce(IV)/Ce(III) could enhance the activation of O 3 to produce more ·OH and 1 O 2 for the organic molecules mineralization.
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Food Chemistry-X
·
2026
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IF 9.2
Jiaxuan Tang,Wenru Wang,Weina Yu,Qiuran Wang,Yunxuan Li,Conglin Feng,Jianhang Yang,Yifei Pan,Xiaodong Cao,Shudong He,Yuhan Sun,Yongkang Ye,Haisong Zheng
Herein, Mn-doped carbon dots (Mn-CDs) were prepared and used as a reducing agent to reduce PtCl 6 2− to platinum nanoparticles (Pt NPs), forming a stable nanozyme of Mn-CDs@Pt NPs. The prepared Mn-CDs@Pt nanozyme exhibited high oxidase-like activity toward the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with a low Michaelis-Menten constant ( K m ) value of 0.0545 mM and a high maximum initial velocity ( V max ) value of 3.42 × 10 −7 M s −1 . By exploiting the excellent oxidase-like activity of Mn-CDs@Pt nanozyme and combining the thiol-ene Michael addition between glutathione (GSH) and acrylamide (AA), a sensitive colorimetric detection interface for AA was fabricated. Using UV–vis measurement, the colorimetric sensor for AA detection displayed a broad linear detection range from 0.05 to 5000 μM and a detection limit (LOD) of 0.0371 μM. In addition, a smartphone-assisted detection of AA yielded a linear range from 5 to 5000 μM with an LOD of 4.35 μM. The colorimetric sensor was applied for AA detection in real samples, achieving satisfactory recoveries in the range of 94.8–110.4%. Moreover, the detection results of AA in real samples were in good consistency with those detected using the standard method of HPLC, suggesting that the proposed colorimetric method possesses potential for AA detection in food safety and quality monitoring.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Ziyun Zhang,Hanghang Hui,Qian Chen,Zhiyuan Wang,Runguo Zheng,Hongyu Sun,Yanguo Liu
Mn-based layered oxides with high theoretical capacity are one of the most promising cathode materials for potassium-ion batteries. However, the Jahn-teller distortion of Mn 3+ in Mn-based layered cathodes always brings about harmful disordered structure and irreversible phase transition, resulting in severe degradation of electrochemical performance. Herein, we synthesized P3–K 0.5 Mn 0.6 Ni 0.2 M 0.2 O 2 (M = Fe, Co, FeCo) and systematically investigate the effect of component regulation on the layered structure and electrochemical properties. The P3–K 0.5 Mn 0.6 Ni 0.2 Co 0.2 O 2 exhibits a discharge capacity of 73.77 mAh g −1 , demonstrating an excellent capacity retention rate of 70.17 % after 120 cycles at 50 mA g −1 . In-depth analysis reveals that P3–K 0.5 Mn 0.6 Ni 0.2 Co 0.2 O 2 possesses a larger K + layer spacing, making the insertion/extraction of potassium ions become much easier. Furthermore, the introduction of Co into the transition metal layer enhances the content of Mn 4+ , thereby inhibiting Jahn-Teller distortion and improving structural stability. Especially, the P3–K 0.5 Mn 0.6 Ni 0.2 Co 0.2 O 2 shows a highly reversible single-phase solid solution reaction during the initial cycle, which means the detrimental phase transition of P3–O3 caused by Jahn-Teller effect is effectively suppressed. This work contributes to a better understanding of the effect of component design and regulation on the performance of the layered oxides cathode and provide insight into the design of high-performance cathode materials for potassium-ion batteries.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Wei Wang,Zhulin Han,Haiwang Wang,Xinfang Wei,Ruixia Zhong,Jian Qi
In this paper, CoMn based nanowires were in-situ grown on foam nickel by hydrothermal method combined with calcination treatment, and a monolithic methane oxidation catalyst was obtained. The effects of hydrothermal temperature and calcination temperature on the crystal structure, micro morphology and catalytic performance of the catalysts were systematically studied. The results indicated that when the hydrothermal temperature was 160 °C and the calcination temperature was 350 °C, Mn doped Co 3 O 4 nanowires with uniform morphology can be obtained, accompanied by the appearance of CoMn 2 O 4 . The introduction of Mn ions caused lattice distortion of Co 3 O 4 , achieving the regulation of adsorbed oxygen and lattice oxygen. The monolithic MnCoO/NF–H-160 °C catalyst showed the best catalytic activity (T 90 = 414 °C) for lean methane catalytic oxidation, which even surpassed the noble metal based catalyst. Its excellent catalytic activity was due to the fact that the catalyst can expose more active sites, rich active oxygen and good mass transfer characteristics. This study provides a new approach for designing efficient monolithic catalysts and has significant potential for application and development in the field of organic waste gas treatment.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Yuan Li,Miao-Ying Chen,Bang-An Lu,Hao-Ran Wu,Jia-Nan Zhang
Although the Mn-N-C catalyst has low toxicity and high durability, its intense pH-dependent ORR activity is perplexing and prevents its commercial use in PEMFCs. Herein, we have developed a novel understanding of the role of hydrogen peroxide in the pH-dependent activity and stability of Mn-N-C catalysts. Instead of nitrogen protonation, the strong pH effects of ORR activity are caused by the much faster kinetics of the H 2 O 2 reduction reaction in alkaline medium than in acid, due to the lower dissociation energy of the HO-OH bond in alkaline environment. Regarding durability, the deactivation induced by H 2 O 2 demonstrates a strong pH dependence, primarily due to the differing intensities of reactive oxygen species at different pH values. Correspondingly, isopropanol effectively reduces Fenton reagents and increases the acid resistance of Mn-N-C sites. The present research provides a mechanistic understanding of pH effects and paves the way for the creation of more efficient catalysts.
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高影响因子
LANGMUIR
·
2023
·
IF 3.9
Qiang Ma,Lijun Jiang,Bowen Yang,Bowen Xu,Qingyuan Wang,Qihong Wu,Ping Ning,Yingjie Zhang,Jin Huang,Jiming Hao
Gaseous thallium (Tl) pollution events, primarily caused by non-ferrous mineral refineries and fossil fuel combustion, have increased over the past few decades. To prevent gaseous Tl distribution from flue gas, MnO2/CeO2@HKUST-1 (MCH) was synthesized and found to achieve a gaseous Tl(I) removal level of up to 90% at 423 K, a weight hourly space velocity (WHSV) of 2000 h–1/mL with an Mn dose of 10%, maintained over 10 h. The best Mn/Ce ratio was found to be 9:1. To further investigate surface kinetic behavior, four commonly used kinetic models were applied, including the Eley–Rideal (ER) model, Langmuir–Hinshelwood (LH) model, Mars–van Krevelen (MVK) model, and pseudo-first-order (PFO) model. While the ER and LH models had the slightest deviation, the MVK model was the most reliable. The CatMAP software was also used to match the simulation deviation. This work demonstrated the Tl removal mechanism and provided insights into the accuracy of kinetic models on minor-radius heavy metal. Thus, this research may help promote the design of reactors, heavy metal removal rates, and flue gas purification technology selection.
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PubMed
高影响因子
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