ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Qianlin Huang,Puzhen Zhao,Weiwei Wang,Lu Lv,Weiming Zhang,Bingcai Pan
Cost-efficient and durable manganese-based catalysts are in great demand for the catalytic elimination of volatile organic compounds (VOCs), which are dominated not only by the nanostructures but also by the oxygen vacancies and Mn–O bond in the catalysts. Herein, a series of nanostructured Co–Fe-doped-δ-MnO2 catalysts (Co–Fe-δ-MnO2) with high dispersion were in situ fabricated by employing metal–organic-frameworks (MOFs) as reducing agents, dopants, and templates all at the same time. The as-obtained Co–Fe-δ-MnO2-20% catalyst exhibited robust durability and high catalytic activity (225 °C) for toluene combustion even in the presence of 5 vol % water vapor, which is 50 °C lower than that of pristine δ-MnO2. Various characterizations revealed that the homogeneously dispersed codoping of Co and Fe ions into δ-MnO2 promotes the generation of oxygen vacancies and weakens the strength of the Mn–O bond, thus increasing the amount of adsorbed oxygen (Oads) and improving the mobility of lattice oxygen (Olatt). Meanwhile, due to successfully inheriting the framework structures of MOFs, the obtained catalyst exhibited a high surface area and three-dimensional mesoporous structure, which contributes to diffusion and increases the number of active sites. Moreover, in situ DRIFTS results confirmed that the toluene degradation mechanism on the Co–Fe-δ-MnO2-20% follows the MVK mechanism and revealed that more Oads and high-mobility Olatt induced by this novel method contribute to accumulating and mineralizing key intermediates (benzoate) and thus promote toluene oxidation. In conclusion, this work stimulates the opportunities to develop Co–Fe-δ-MnO2 as a class of nonprecious-metal-based catalysts for controlling VOC emissions.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2025
·
IF 1.7
Cheng Lijun,Lei Juan,Ren Xiaoli,Chang Hong,Ju Baihe
In this study, a series of La-α-MnO 2 catalysts with different La doping amounts were prepared by hydrothermal method. It was found that the introduction of La could reduce the crystallinity of α-MnO 2 and increase the specific surface area of the catalyst. Furthermore, La doping can significantly weaken the Mn–O bond, increase the surface Mn 3+ and O ads content, and enhance the oxygen mobility and low-temperature reducibility. The catalytic results indicated that La doping could significantly improve the catalytic oxidation performance of toluene, and 1%La-α-MnO 2 catalyst exhibited the best catalytic activity for toluene oxidation. The toluene conversion rate reaches 90% when the reaction temperature is only 215 °C. In addition, 1%La-α-MnO 2 catalyst presented good stability and repeatability during 50 h durability test under water vapor.
研究领域:
催化化学
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环境科学
·
材料化学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Energy Materials
·
2025
·Vol. 15
·期 34
·2502226
·
IF 26
Mengting Guo,Changping Wang,Yize Niu,Mingyue Ruan,Dong Yang,Fei Wang,Haonan Wang,Nankai Wang,Ying Jiang,Tianyi Li,Yan He,Qiang Li
The high-voltage spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) is a promising cathode material for lithium-ion batteries due to its high energy and power densities, excellent thermal stability, low cost, and environmental benignity. However, the presence of Mn 3+ induces Jahn─Teller (J─T) distortion, leading to Mn─O bond elongation, lattice stress, and degradation of both structural and electrochemical stability during cycling. To address this,a bond-length engineering strategy is proposed by co-doping Fe at the Mn 16d sites and Sb at the vacant 16c positions to suppress the J─T effect and stabilize the crystal structure. Electron paramagnetic resonance (EPR), in situ X-ray diffraction (XRD), and density functional theory (DFT) calculations confirm that the Mn─O bond regulation strategy effectively mitigates MnO 6 octahedral distortion, reduces phase transitions, and enhances structural robustness. Moreover, Sb incorporation expands the lattice, facilitating Li + diffusion. As a result, the optimized FeSb-LNMO delivers remarkable electrochemical performance, retaining 98% of its initial capacity after 200 cycles at 1C, and achieving 85.6% capacity retention over 1000 cycles at 5C. This work introduces a novel bond-length engineering approach via multi-site doping to overcome degradation in high-voltage LNMO, enabling ultra-fast charging and long-term cycling stability.
研究领域:
材料科学
·
电化学
·
储能
·
电池技术
·
固态化学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2022
·Vol. 18
·期 13
·2106863
·
IF 15.153
Jie Huang,Yeqing Chen,Pengpeng Rao,Zongming Ni,Xueying Chen,Jie Zhu,Chen Li,Gaoyang Xiong,Ping Liang,Xin He,Songnan Qu,Jun Lin
Carbonized polymer dots (CPDs) have received tremendous attention during the last decade due to their excellent fluorescent properties and catalytic performance. Doping CPDs with transition metal atoms accelerates the local electron flow in CPDs and improves the fluorescent properties and catalytic performance of the CPDs. However, the binding sites and the formation mechanisms of the transition-metal-atom-doped CPDs remain inconclusive. In this work, Mn 2+ -ion–doped CPDs (Mn-CPDs) are synthesized by the hydrothermal method. The Mn 2+ ions form Mn O bonds that bridge the sp 2 domains of carbon cores and increases the effective sp 2 domains in the Mn-CPDs, which redshifts the fluorescence emission peak of the Mn-CPDs slightly. The Mn 2+ ions form covalent bonds in the CPDs and remedy the oxygen vacancies of the CPDs, which cuts off the non-radiative–recombination process of the Mn-CPDs and increases the quantum yield of the Mn-CPDs to 70%. Furthermore, the Mn O bonds accelerate the electron flow between adjacent sp 2 domains and enhances the electron transport in the Mn-CPDs. Thus, the Mn-CPDs demonstrate excellent catalytic performance to activate hydrogen peroxide (H 2 O 2 ) and produce hydroxyl radicals (•OH) to degrade methylene blue (MB) and rhodamine B (RhB).
研究领域:
材料科学
·
纳米技术
·
催化
·
光化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）