Separations
·
2025
·Vol. 12
·期 12
·
IF 2.7
Meiqing Chen,Wenjie Dai,Yingying Liu,Guanzheng Zhuang,Yanfu Wei,Zhi Dang,Pingxiao Wu
Birnessite has a strong ability to fix rare-earth elements (REEs), but the transformation process of birnessite and its effects on the migration of these elements are not well understood. This study examines how pH and Mn(II) concentrations influence the transformation of cerium-adsorbed hexagonal birnessite (Ce/HB) and the behaviors of Ce and Mn. The results show that the effect of Mn(II) on Ce/HB transformation strongly depended on solution pH. At a pH of 5.0, HB initially underwent transformation into feitknechtite, followed by further disproportionation that resulted in the regeneration of HB and Mn(II). Concurrently, redox reactions occur between Mn(IV) in MnO2(a secondary phase of HB) and Ce(III)/Mn(II), creating a local redox gradient that facilitates partial HB transformation. At pH = 7.0, Mn(II) reduces the crystallinity of transformed products while enhancing the thermodynamic stability of feitknechtite, making it the dominant manganese oxide phase. At pH = 9.0, high-concentration Mn(II) causes lattice distortion in original HB; Ce(III) acts as a structural inducer, promoting mineral transition from hexagonal to orthorhombic symmetry, while excess soluble Mn(II) precipitates new feitknechtite. Additionally, surplus Mn(II) could engage in interfacial redox reactions with high-valent manganese oxides to generate secondary feitknechtite. Ce primarily exists as Ce(IV), forming CeO2on the mineral surface via oxidation reactions that significantly increase hydroxylation and surface reactivity. This study clarifies the transformation pathways of manganese oxides and the migration and transformation patterns of Ce and Mn in rare-earth-rich mining areas.
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ACS Nano
·
2025
·
IF 16
Shunli He,Robert Scott Young,Xing Shen,Miao Han,Yaoguang Song,Wenyi Dong,Yiming Zhang,Jili Yue,Jingfeng Wang,Rhodri Jervis,Junmei Zhao,Alexander J. E. Rettie
Mn-based layered oxides are promising cathode materials for sodium-ion batteries (SIBs) due to their high capacity and cost-effectiveness. However, their practical application is often hindered by structural instability and Jahn–Teller distortion associated with Mn3+. Herein, an ionic-potential-guided metal-fluoride engineering strategy is proposed to address these challenges by coincorporating AlF3 with transition-metal vacancies into a P2-type Mn-based layered oxide (Na0.76Ni0.225Al0.0167Mn0.75O1.95F0.05). This dual-site tuning elevates total ionic potential from 15.37 to 15.61 by simultaneously enhancing the cationic potential and reducing the anionic contribution, thereby promoting interlayer stability and suppressing Jahn–Teller effects. Multiscale characterization and density functional theory calculations reveal a reversible, solid-solution Na+ (de)intercalation mechanism with a negligible lattice strain (∼0.15%) and suppressed Mn3+ formation. The optimized cathode delivers an average voltage of ≈3.60 V within 2.0 to 4.3 V range, a reversible capacity of 134 mA h g–1, and 83% capacity retention after 100 cycles (2.0–4.3 V, 1C). In contrast, the pristine counterpart shows a lower average voltage of 3.32 V and a rapid capacity drop to ∼50 mA h g–1 by the second cycle. These findings establish the ionic-potential-guided AlF3 incorporation as a robust and scalable strategy for designing highly reversible, high-voltage, and long-life cathodes for next-generation SIBs.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2025
·Vol. 36
·期 14
·831
·
IF 2.8
Zhao Tianqun,Zeng Tianrui,Jin Shilei,Li Xiaohui,Yu Zhiqiang
BNT (BaO–Nd 2 O 3 –TiO 2 ) system was modified via doping using sol–gel method, and BNST-Mn/PTFE microwave dielectric composite was prepared by mechanical blending. Scanning electron microscopy (SEM), thermal dilatometer, and split post-dielectric resonator (SPDR) were used to characterize the microstructure, dielectric properties, and thermal properties of the composite materials. The results indicate that as the amount of ceramic filler supplied grows, the agglomeration of fillers becomes more pronounced. At a filler content of 10 wt%, the dispersion of the filler in the matrix resin is relatively uniform. The dielectric constant and dielectric loss of the composites increased, and the bonding ability between the two phases diminished with the increase in filler content. When the mass fraction of the ceramic was increased to 70 wt%, the dielectric constant of the composite was 10.92 and the Q·f value was measured at 3584 GHz. At the same time, the coefficient of thermal expansion (CTE) of the composites reached 23 ppm/°C, which was a good compatibility with the copper foil. Lichtenecker equation, Maxwell–Wagner equation, Jayasundere–Smith equation, and effective medium theory equation (EMT) were used to predict the dielectric constant of the composites. In comparison, the dielectric constant values calculated using the EMT equation were in good agreement with the experimental values, especially at low filling volumes. Also, the simulation results of the thermal expansion coefficient of composite materials using the Lichtenecker equation and its improved form are in good agreement with the experimental values.
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ANALYTICA CHIMICA ACTA
·
2025
·
IF 6
Lin Wang,Yue Wang,Xiao-Jie Shi,Tian-Shun Song,Xiang-Ling Li,Jing-Jing Xie
Background Rapid, low-cost measurement of glutathione (GSH) is valuable for judging food freshness. However, many colorimetric assays depend on natural enzymes or added H 2 O 2 , which limits stability and use in real samples. Results We developed a manganese single-atom enzyme (Mn/SAE) with intrinsic oxidase-like activity to build an enzyme-free, H 2 O 2 -free colorimetric system for GSH. Mn/SAE uses dissolved O 2 to oxidize TMB to blue oxTMB; GSH reduces oxTMB back to TMB, producing a decrease in color and absorbance for readout. Under optimized conditions, both the solution assay and a paper-based analytical device (PAD) provide results within 10 min using smartphone R-channel quantification. The method shows good selectivity and performs well in real samples, tracking the expected decline of GSH in strawberries during storage. Significance This simple, low-cost, and portable approach enables on-site GSH analysis without enzymes or H 2 O 2 . The Mn/SAE colorimetric system offers practical value for freshness monitoring and can be adapted to other redox biomarkers in food-quality assessment.
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Materials
·
2019
·Vol. 12
·期 22
·3654
·
IF 2.972
Mingxuan Ma,Xiaoyu Ma,Suping Cui,Tingting Liu,Yingliang Tian,Yali Wang
A series of MCM-41 molecular sieves with different molar ratio of template to silicon were synthesized through hydrothermal synthesis method by using cetyltrimethylammonium bromide (CTAB) as the template, diatomite as the silicon source. By using impregnation method, the Mn-Ce/MCM-41 SCR molecular sieve-based catalysts were prepared. The results observed that when the molar ratio of template to silicon was 0.2:1, the MCM-41 as catalyst carrier has the highest surface area and largest pore volume, it also presented typically ordered hexagonal arrays of uniform channels. The denitration catalytic material based on this carrier has a high number of Lewis acidic sites, and the denitration efficiency can reach more than 93%.
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Journal of Materials Chemistry A
·
2023
·Vol. 11
·期 25
·13720-13728
·
IF 11.9
Zheng Ma,Yubo Luo,Wang Li,Yingchao Wei,Chengjun Li,Abubakar Yakubu Haruna,Zhihong Zhang,Xin Li,Qinghui Jiang,Junyou Yang
Point defects play an important role in regulating the electrical and thermal transport properties of thermoelectric materials, but it is always restricted by the solubility of dopants in the matrix. Herein, we demonstrate an effective route to enhance the solubility of Mn from 8% up to 30% in AgSbSe2 through entropy-driven alloying with MnSe. It enables us to largely enhance the carrier concentration and electrical conductivity and also reduce the lattice thermal conductivity of AgSbSe2. As a consequence, (AgSbSe2)0.7(MnSe)0.3 has a high ZT of ∼0.96 at 750 K. Moreover, a further enhanced ZT of 1.18 was achieved in (AgSbSe2)0.7(Mn0.99Se)0.3 at 750 K by the introduced Mn vacancies.
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JOURNAL OF COORDINATION CHEMISTRY
·
2012
·
IF 1.547
Li Zhang,Xiu-Ling Wu,An-Qi Wang,Fei Qin,Da-Wei Meng,Xiao-Yang Liu
A manganese(II) coordination polymer [Mn(TMB)2 · H2O]
n
(1) (HTMB = 3,4,5-trimethoxybenzoic acid) has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction analysis, spectroscopic (IR, solid state UV-Vis), and thermal methods. The crystal belongs to orthorhombic system, space group P212121, with cell parameters a = 7.3001(8), b = 11.4146(13), c = 27.053(3) Å, α = β = γ = 90°, V = 2254.3(4) Å3, Z = 4. In 1, TMB in two different coordination modes bridges six-coordinate manganese(II) centers forming a 1-D infinite chain coordination framework. The spectral and thermal properties of the complexes have also been studied.
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Sustainable Energy & Fuels
·
2024
·Vol. 8
·期 23
·5524-5534
·
IF 5
Yihong Zhu,Juping Zhang,Dongfang Li,Tao Zhu,Xing Zhu
Chemical looping dry reforming of methane (CL-DRM) is an efficient pathway for the conversion of methane and CO2 into synthesis gas ready for the Fischer–Tropsch process, which largely depends on the redox behavior of oxygen carriers. Perovskite-structured metal oxides are promising candidates for CL-DRM due to the structural diversity brought about by elemental doping. Herein, we proposed to fabricate a highly active oxygen carrier via functionally designed Mn-based perovskite oxides via polymetallic doping. Cu-doping in the B-site of SrMnO3−δ reveals a significant anti-coking effect in the high-temperature continuous CH4/CO2 redox process. Ni-doping in the B-site boosts the performance of methane activation resulting in high methane conversion. Moreover, Ce-doping in the A-site elevates oxygen migration and enhances partial oxidation of methane to H2 and CO as well as the re-oxidation of reduced perovskite oxides. Considering the roles of Cu, Ni and Ce doping of SrMnO3−δ, a polymetallic-doped perovskite of Sr0.8Ce0.2Mn0.7Cu0.1Ni0.2O3−δ was synthesized and evaluated in CL-DRM. The optimized perovskite oxide demonstrated exceptional performance with a methane conversion of 85% and a CO selectivity of 93% throughout 30 redox cycles at 850 °C. In the redox reactions, the transition metals of Mn, Cu, and Ni agglomerated during the reduction but could return to a well-dispersed state after re-oxidization with CO2. The perovskite oxide exhibits self-structural-regenerability and the nano-scale agglomeration–dispersion cycle ensures the high structural stability of the material in the successive CL-DRM cycles. This study provides an important insight into the regulation of catalytic activity, oxygen mobility and carbon-resistance via doping of perovskite oxides with various kinds of compatible elements in both A and B sites.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Xiangyu Zi,Xiaolong Sun,Fengwei Yin,Jia Gao,Jie Huang,Yingying Zhang,Yao Chen,Yongqian Fu
MOFs represent a promising platform for enzyme immobilization, yet the development of tailored strategies to accommodate both enzyme properties and MOF structures remains a challenge. In this study, we employed chitosanase BCC1 as a model enzyme and integrated Fe 2+ /Mn 2+ ions into the ZIF-8 to construct a bimetallic MOF-based immobilization system (BCC1@Fe/Mn-ZIF-8). Comprehensive characterization by SEM, FTIR, TGA confirmed the successful immobilization and structural integrity of the composite. The immobilized enzyme retained 97 % of its initial activity and exhibited enhanced stability under harsh thermal, pH, and solvent conditions. Notably, BCC1@Fe/Mn-ZIF-8 maintained 117 % activity after 14 days at 4 °C and 72 % residual activity after 14 reuse cycles, indicating excellent storage and reusability. This bimetallic MOF-based strategy offers a robust and efficient approach for enzyme immobilization, with strong potential in industrial biocatalysis.
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Royal Society Open Science
·
2025
·Vol. 12
·期 11
·
IF 2.9
Omar Mirna,Omar Sarah,El-Subruiti Gehan M.,Attia Nour F.,Eltaweil Abdelazeem
With growing concerns over water pollution and depletion of freshwater resources, finding sustainable and cost-effective solutions for water treatment is crucial. This study introduces a novel MIL-53(Fe)/Mn-doped SrTiO3 (MIL-53(Fe)/Mn-STO) direct Z-scheme photocatalyst, designed to efficiently degrade organic contaminants in water. Specifically, the photocatalytic degradation of o-nitrophenol (ONP) was investigated under an Xe lamp. The MIL-53(Fe)/Mn-STO photocatalyst demonstrated a maximum removal efficiency of 97.75% within 90 min, with a rate constant (k) of 0.0374 min−1, outperforming the individual MIL-53(Fe) and Mn-STO photocatalysts. A comprehensive analysis of the material’s properties was conducted using Fourier transform Infrared spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, diffuse reflectance spectroscopy and photoluminescence techniques, and the photocatalytic activity was evaluated under various conditions, including variations in pH, ONP concentration, catalyst dosage and the presence of inorganic anions. The improved photocatalytic activity of the MIL-53(Fe)/Mn-STO system can be ascribed to the synergistic interaction between its two components, which also contributed to its excellent recyclability over five cycles. These findings demonstrate that MIL-53(Fe)/Mn-STO is a highly effective and sustainable photocatalyst with a strong potential for wastewater treatment applications.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2026
·Vol. 46
·期 8
·118152
·
IF 6.2
Ziqin Lin,Tianxia Xie,Zhuolin Xie,Anqi Dai,Yang Yuan,Peng Sun,Yanqi Song,Zhenggang Fang,Chunhua Lu
Solar absorbers are vital for concentrated solar power (CSP) systems, yet spectral selectivity solar absorbers (SSAs) struggle with high-temperature stability in air. This study introduced Mn ions into MgTiO 3 (MTO) via a high temperature solid-phase synthesis technique to optimize the spectral selectivity. Unlike conventional doping that increased both absorptance and emittance, MgTi 0.4 Mn 0.6 O 3 (MTMO-0.6) boosted solar absorptance (α = 0.85) while maintaining low emittance (ε = 0.39, 1073.15 K) in the 2.5–15 μm wavelength range. Besides, the material retained high spectral selectivity (α/ε = 0.84/0.41) after heat treatment at 800 °C in air atmosphere for 90 h in total (9 h cycles −1 , 10 cycles), showing excellent thermal stability. Moreover, under concentrated solar irradiation of 10.83 W·cm −2 , MTMO-0.6 sample reached an equilibrium temperature of 848 ℃, surpassing that of MTO and SiC. The proposed Mn-doped MgTiO 3 has the potential as a solar absorber for high temperature solar thermal conversion.
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RSC Advances
·
2017
·Vol. 7
·期 77
·49091-49096
·
IF 3.108
Lina Xue,Ka Xiong,Haijun Chen,Kyeongjae Cho,Weichao Wang
Hydrothermal aging tests are important to carry out when evaluating the hydrothermal durability of heterogeneous catalysts in vehicle exhaust emission. Here, we explored the effect of aging on an efficient Mn-based mullite catalyst (SmMn2O5) of NO oxidation. The mullite catalyst was prepared via the hydrothermal method and was subsequently aged in air with a 10% H2O stream at 750 °C for 16 hours. The fresh and aged catalysts were structurally characterized using Powder X-ray diffraction(XRD), Raman, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), high resolution-transmission electron microscope (HR-TEM), Brunauer–Emmett–Teller (BET) and temperature programmed desorption (TPD). For the performance evaluations, the samples were placed into a U-shape reactor furnace, and NO and NO2 concentrations were in situ recorded with an NOx analyzer. In contrast to fresh mullite, the aged sample showed a 25 °C higher light-off temperature and 11% conversion loss at its maximum conversion temperature of 300 °C. O2-TPD of the aged sample displayed a large decrease of the desorption area, consistent with an ∼3-fold loss of the BET specific surface area. Moreover, HRTEM, XPS and Raman spectroscopy results together indicated that a small portion of the mullite decomposed into perovskite SmMnO3 and Mn2O3, which further reduced the total quantity of Mn active sites. The reduction of the BET surface area and mullite decomposition together caused the decrease of the catalytic performance. We therefore expect maintaining the specific surface area to be important for preventing the loss of catalytic performance during the hydrothermal aging process.
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