SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Wenjing Zong,Zhaoming Guo,Minghuo Wu,Xianliang Yi,Hao Zhou,Siyuan Jing,Jingjing Zhan,Lifen Liu,Yang Liu
Endocrine-disrupting chemicals (EDCs) cause serious threats to human health. Five types of MnO 2 were synthesized and characterized. They exhibited different removal performances for three EDCs, i.e., estrone (E1), ethynylestradiol (EE2) and bisphenol A (BPA). Only δ-MnO 2 can completely remove E1 within 120 min at pH 3.0. Free Mn (III) was determined at the beginning of the reaction and participated in the EDCs removal process. Electron spin resonance (ESR) indicated that δ-MnO 2 could produce superoxide anions (·O 2 − ) and singlet oxygen ( 1 O 2 ) in the existence of methanol. The reactive oxygen species (ROS) quenching experiments showed 1 O 2 have certain contribution to the E1 removal by δ-MnO 2 . The source of ROS is mainly the lattice oxygen from δ-MnO 2 , and can be replenished through the layer structure destruction caused by the reaction between Mn(III) and E1. The ROS dependent EDCs removal by δ-MnO 2 leads to a deep understanding on this well-known oxidant.
研究领域:
环境科学
·
化学工程
·
水处理
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DOI
PubMed
高影响因子
Science China-Materials
·
2024
·Vol. 67
·期 4
·1340-1347
·
IF 6.8
Cao Mengyan,Li Renfu,Li Zhilin,Zhao Xiujian,Gong Xiao
Perovskite crystals with high photoluminescence quantum yields can be rapidly synthesized by doping Mn 2+ into Cs 2 ScCl 5 ·H 2 O through a facile wet chemistry approach. The quantum yield of the Mn 2+ -doped perovskite crystals in the red light region is over 12 times higher than that of the host material and nearly 24 times higher than that of pure Mn-based perovskite CsMnCl 3 ·2H 2 O. Moreover, density functional theory calculations were used to study the orbital hybridization properties of the materials to further investigate their optical properties. After Mn 2+ doping, the Mn octahedrons separated by the Sc octahedrons can more effectively restrict excitons, which is conducive to the improvement of quantum yields. Compared with the original band gap, a new hybridized orbital attributed to Mn and the host element appears. The doped sample shows an extended absorption and excitation range from the original deep-ultraviolet (UV) absorption to UV and visible absorption. Based on these properties, the Mn 2+ -doped perovskites are used to prepare efficient white light-emitting diodes excited by a blue chip, showing an excellent color rendering index of 91, which meets the need for future applications in the field of optoelectronics.
研究领域:
材料科学
·
光电子学
·
无机化学
·
固体物理
·
纳米技术
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DOI
高影响因子
Journal of Physical Chemistry Letters
·
2023
·
IF 5.7
Yacong Li,Chuying Wang,Guangyong Xu,Guigen Luo,Zhengtao Deng
The absorption and photoluminescence (PL) of CsMnBr3 with Mn(II) in octahedral crystal fields are extremely weak due to a d–d forbidden transition. Herein, we introduce a facile and general synthetic procedure that can prepare undoped and heterometallic doped CsMnBr3 NCs at room temperature. Importantly, both PL and absorption of CsMnBr3 NCs were significantly improved after doping a small amount of Pb2+ (4.9%). The absolute photoluminescence quantum yield (PL QY) of Pb-doped CsMnBr3 NCs is up to 41.5%, 11-fold higher than undoped CsMnBr3 NCs (3.7%). The PL enhancement is attributed to the synergistic effects between [MnBr6]4– units and [PbBr6]4– units. Furthermore, we verified the similar synergistic effects between [MnBr6]4– units and [SbBr6]4– units in Sb-doped CsMnBr3 NCs. Our results highlight the potential of tailoring luminescence properties of manganese halides through heterometallic doping.
研究领域:
材料科学
·
纳米技术
·
光电子学
·
无机化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2024
·
IF 5.7
Ruijing Fu,Junpeng Gao,Pinsen Zhang,Lingrui Wang,Bo Wang,Guangxia Wang,Xiaoshuang Li,Youchao Kong,Qingguang Zeng,Guanjun Xiao
Manganese (Mn)-based organic–inorganic metal halides (OIMHs) are extensively employed in various optical applications due to their non-toxicity, superior optical properties, and tunable emission advantages. Developing effective strategies to enhance the optical properties of these materials and clarifying their structure–optical property relationships continue to be of significant interest. Here, we report that the zero-dimensional (0D) (C24H20P)2MnBr4 exhibits remarkable pressure emission tuning that shifts from green to red, a phenomenon driven by the enhancement of the crystal field splitting energy and the reduced energy difference of the lowest d–d transition (4T1 → 6A1) motivated by the shortening of Mn–Br bonds. Additionally, the band gap value of (C24H20P)2MnBr4 becomes 3.13 eV, showing an unexpected decrease by 1.09 eV from an initial value of 4.22 eV, when the pressure is released from 31.0 GPa. The incomplete recovery of the distortion in [MnBr4]2− tetrahedra, impeded by the distortion of soft organic macromolecules, is believed to be responsible for band gap narrowing. Combined with computations and subsequent experiments, it is inferred that pressure induced reduction in the Mn–Br bond distance contributes to the distortion of tetrahedral [MnBr4]2− and larger-sized organic cations. Our work not only elucidates the structure–optical property relationships in Mn-based OIMHs, but also opens new avenues for modulating their optical properties and devising innovative strategies for designing novel Mn-based OIMHs.
研究领域:
材料科学
·
光学
·
化学
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DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2023
·Vol. 101
·期 12
·6807-6816
·
IF 2.1
Renjie Deng,Wenjin Ni,Yao Tian
Bimetallic cerium-manganese modified Hβ zeolite sample (Ce/Mn-Hβ) was prepared by ultrasonic assisted impregnation method and applied in nitration of toluene. The characterization results show that the active components (Ce and Mn) are successfully introduced into the framework of Hβ zeolite. The catalyst shows excellent catalytic activity and reusability for the nitration of toluene, giving high para selectivity. Under optimized conditions, it gives 68.7% selectivity to para -nitrotoluene at 88.6% conversion over Ce/Mn-Hβ in the presence of acetic anhydride (Ac 2 O). The theoretical calculations indicate that the Ce/Mn bimetallic active sites in modified Hβ zeolite can easily activate the nitrification reagent (AcONO 2 ), and the enhancement of para selectivity is owing to the steric hindrance of catalyst. Furthermore, the reaction mechanism was proposed by the combination of experimental results and theoretical calculations.
研究领域:
化学工程
·
催化材料科学
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DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 20
·5958
·
IF 3.623
Xusheng Ren,Zhiliang Ou,Bang Wu
The activated coke is a promising support for catalysts, and it is important to study the performance of the activated coke catalyst on the removal of NOx. In the current research, a series of the activated coke-supported Mn–Cu catalysts are prepared by the incipient wetness impregnation method. The effects of the molar ration of Mn/Cu, the content of Mn–Cu, the calcination temperature, and reaction space velocity on NO conversion are investigated, and it was found that the 8 wt.% Mn0.7Cu0.3/AC had the best catalytic activity when the calcination temperature was 200 °C. The existence of SO2caused the catalyst to deactivate, but the activity of the poisoning catalyst could be recovered by different regeneration methods. To uncover the underlying mechanism, BET, XPS, XRD, SEM and FTIR characterizations were performed. These results suggested that the specific surface area and total pore volume of the poisoning catalyst are recovered and the sulfite and sulfate on the surface of the poisoning catalysts are removed after water washing regeneration. More importantly, the water washing regeneration returns the value of Mn3+/Mn4+, Cu2+/Cu+, and Oα/Oβ, related to the activity, basically back to the level of the fresh catalyst. Thus, the effect of water washing regeneration is better than thermal regeneration. These results could provide some helpful information for the design and development of the SCR catalysts.Keywords:activated coke;low-temperature NH3-SCR;sulfur poisoning;regeneration
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
NANOTECHNOLOGY
·
2023
·Vol. 34
·期 14
·145403
·
IF 3.5
Huiying Wang,Ziyan Kong,Minghao Wang,Bing Huang,Lunhui Guan
Manganese and nitrogen co-doped porous carbon (Mn–N–C) are proposed as one of the most up-and-coming non-precious metal electrocatalysts to substitute Pt-based in the oxygen reduction reaction (ORR). Herein, we chose metal triazole frameworks as carbon substrate with hierarchical porosity for trapping and anchoring Mn-containing gaseous species by a mild one-step pyrolysis method. The optimized Mn–N–C electrocatalyst with a large metal content of 1.71 wt% and a volume ratio of 0.86 mesopores pore delivers a superior ORR activity with a half-wave potential (E1/2) of 0.92 V in 0.1 M KOH and 0.78 V in 0.1 M HClO4. Moreover, the modified Mn–N–C catalyst showed superior potential cyclic stability. The E1/2 remained unchanged in 0.1 M KOH and only lost 6 mV in 0.1 M HClO4 after 5000 cycles. When applied as the cathode catalyst in Zn-air battery, it exhibited a maximum peak power density of 176 mW cm−2, demonstrating great potential as a usable ORR catalyst in practical devices.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Chunhao Wang,Haipeng Chen,Jian Deng,Liqing Li,Zheng Zeng,Xiancheng Ma,Siyu Wei
Exploring the single relationship between the inversion degree of spinel and its catalytic performance is a great challenge, but has important significance for further structural design and application. A series of CoMn inverse spinels were prepared and the general formula Co 1 - x 2 + Co x 3+ tet Mn 1 3+ Co x 2+ Co 1 - x 3+ oct O 4 was deduced through X-ray diffraction refinement to find a decreased inversion degree x as calcination temperature rose. Catalytic oxidation of toluene showed that higher inversion degree (S-300 with x ≈ 0.95) can reach larger conversion rate (90 % at about 250 °C for 400 ppm toluene) with greater reaction stability (140 h). Density Functional Theory (DFT) calculations on density of states indicated its metallic nature, and found that the strength of O-p and Transition metal-d orbitals at Fermi energy is positively correlated to the inversion degree, meaning stronger electron migration ability. Along with the adsorption calculation analysis that lattice oxygen species are proved to work dominantly (S-300 with lowest adsorption energy but highest performance), this work uncovered a theoretical insight into inverse spinel oxide , to provide the possibility of elevated oxidation ability through structural control.
研究领域:
催化化学
·
材料科学
·
理论计算化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 43
·22763-22772
·
IF 11.301
Jiaxi Xue,Yajing Wang,Cui Sun,Pan Xu,Xiaoxiang Fan,Jingmin Fan,Mingsen Zheng,Quanfeng Dong
Li-rich Mn-based materials, as high-energy-density and low-cost cathode materials for Li-ion batteries, suffer severe irreversible voltage fading and capacity loss during cycling, associated with the instability of crystal structure at high voltage, which greatly reduces the specific energy density after cycling and thus impedes their commercialization. Here, we introduce a new strategy to mitigate voltage fading and improve the cycling performance of Li-rich Mn-based cathode materials by simply introducing MgSO4 in the cathode during its preparation process. The results show that cycling stability and voltage fading of corresponding batteries were dramatically improved due to the high Li+ retention at the initial charge process and the stable cathode electrolyte interface (CEI) layer. After 100 cycles at 1C, the average discharge voltage decay is only 0.115 V (1.15 mV per cycle), with a high voltage retention of 96.7%, and the capacity remains at 91.5% after 300 cycles at 1C.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 14
·4837-4845
·
IF 6.4
Yao Zhang,Chengpeng Hu,Yu Wang,Xiaolin Huang,Xuejie Sun,Mingxuan Liu,Bohan Xing,Xing Wen,Hao Tian
The improvement of piezoelectric properties is always a key issue in the study of piezoelectric materials. The construction of composition gradient (CG) is a novel method to improve piezoelectric properties. However, the physical mechanism of CG influence on the piezoelectric properties has to be analyzed further. We investigate the origin of the CG-affected piezoelectric property using a manganese-doped potassium sodium niobate single crystal (that is Mn: KNN) as a model system. The relationship between CG, microstructure and spontaneous polarization was explored by designing and growing Mn:KNN single crystals with different CGs. It is found that the built-in electric field (Ein) in single crystals is constructed by introducing the CG in the crystals. The large Ein induces a more ordered, large-sized striated domain structure. The Mn: KNN single crystal with a large CG has a uniform orientation of spontaneous polarization and large macro-piezoelectric properties (83 pC N−1). Therefore, it is important to explore the relationship between CG and the piezoelectric properties of single crystals in lead-free piezoelectric materials. The results can be used to further develop high-performance lead-free piezoelectric materials.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2024
·Vol. 160
·期 16
·
IF 3.1
Du Luchao,An Jie,Katayama Tetsuro,Duan Menghan,Shi XiaoPing,Wang Yunpeng,Furube Akihiro
In recent years, all-inorganic perovskite materials have become an ideal choice for new thin film solar cells due to their excellent photophysical properties and have become a research hotspot. Studying the ultrafast dynamics of photo-generated carriers is of great significance for further improving the performance of such devices. In this work, we focus on the transient dynamic process of CsPbBr 3 /TiO 2 composite systems with different Mn 2+ doping contents using femtosecond transient absorption spectroscopy technology. We used singular value decomposition and global fitting to analyze the transient absorption spectra and obtained three components, which are classified as hot carrier cooling, charge transfer, and charge recombination processes, respectively. We found that the doping concentration of Mn 2+ has an impact on all three processes. We think that the following two factors are responsible: one is the density of defect states and the other is the bandgap width of perovskite. As the concentration of doped Mn 2+ increases, the charge transfer time constant shows a trend of initially increasing, followed by a subsequent decrease, reaching a turning point. This indicates that an appropriate amount of Mn 2+ doping can effectively improve the photoelectric performance of solar cell systems. We proposed a possible charge transfer mechanism model and further elucidated the microscopic mechanism of the effect of Mn 2+ doping on the interface charge transfer process of the CsPbBr 3 /TiO 2 solar cell system.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
PubMed
高影响因子
MATERIALS RESEARCH BULLETIN
·
2024
·
IF 5.3
Jiaping Guan,Guomin Sun,Gaoyuan Yu,Yu Chen,Jiawen Wei,Xiaohui Zhu,Xiaogu Huang
Sodium-ion batteries (SIBs) have garnered significant interest due to their cost-effectiveness and operational similarities to lithium-ion batteries. Amongst the various components, the cathode plays a pivotal role in determining the energy density of these batteries. Mn-based layered oxides stand out as promising cathode materials, owing to their abundance and non-toxicity. However, these oxides tend to suffer from structural instability during high-voltage cycling, leading to a decline in capacity. In this work, we have designed Ce-doped Na 0.6 Li 0.2 Mn 0.79 Ce 0.01 O 2 cathodes through a solid-state reaction process. This innovation aims to inhibit undesirable phase transitions and enhance the electrochemical performance of the electrodes. By integrating electrochemical testing with a suite of characterization techniques, we have shown that 1 mol% Ce doping effectively suppresses the formation of birnessite and the irreversible oxygen redox reactions in the high-voltage region. Moreover, our findings indicate that the detrimental phase transitions can be significantly mitigated throughout the electrochemical cycling process, thereby bolstering structural stability. Notably, the capacity of the Ce-doping cathode after 20 cycles substantially exceeds its initial discharge specific capacity, reaching 169.3 mAh g –1 . This research introduces a strategy for stabilizing the cathode structure of P2-type Mn-based layered oxides through Ce-doping, offering valuable insights for the advancement of next-generation SIBs.
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
危险品化学品经营许可证（带存储）