ADVANCED POWDER TECHNOLOGY
·
2025
·
IF 4.2
Jiaqi Wen,Chenghong Liu,Lihua Gao,Zhijun He
An oxidation roasting technology has been reported as an effective technology for successfully synthesizing nickel manganese ferrite Ni x Mn 1-x Fe 2 O 4 (0 < x < 1) with a spinel crystal structure. The experimental results demonstrated the successful synthesis of nickel manganese ferrite Ni 0.5 Mn 0.5 Fe 2 O 4 samples with relatively high purities at an oxidation roasting temperature of 1200 °C for 2 h with a Ni:Mn:Fe molar ratio of 1:1:4. The synthesized samples exhibited a magnetization saturation (Ms) value of 53.71 emu/g, a coercivity (Hc) value of 34.88 Oe, and a remanent magnetization (Mr) of 3.64 emu/g. Additionally, these samples had a total pore volume of 0.071 cm 3 /g, a Specific Surface Area (SSA) of 24.13 cm 2 /g, and an Average Particle Size (APS) of 12.32 nm. It was concluded that the synthesis route of Ni x Mn 1-x Fe 2 O 4 could be theoretically summarized into two routes. One route involves the simultaneous substitution of divalent iron (Fe 2+ ) and trivalent iron (Fe 3+ ) in the spinel structure of (Fe)[Fe] 2 O 4 by divalent manganese ions (Mn 2+ ) and trivalent nickel ions (Ni 3+ ), resulting in the formation of (Mn) x (Fe) 1-x [Ni] y [Fe] 2-y O 4 with a spinel crystal structure. In this structure, the Ni 3+ ions preferentially occupy the octahedral sites, whereas the Mn 2+ ions predominantly reside in the tetrahedral sites of the nickel manganese ferrites (Mn) x (Fe) 1-x [Ni] y [Fe] 2-y O 4 . Furthermore, the mixed spinel crystal structure of (Ni) y (Fe) 1-y [Mn] x [Fe] 2-x O 4 could be transformed into nickel manganese ferrite (Mn) x (Fe) 1-x [Ni] y [Fe] 2-y O 4 under the influence of a higher oxidization roasting temperature. Nickel manganese ferrite Ni x Mn 1-x Fe 2 O 4 (0 < x < 1) with normal and inverse spinel structures inevitably coexists and co-transformed in the synthesis process of Ni x Mn 1-x Fe 2 O 4 by oxidation roasting technology.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Energy Technology
·
2021
·Vol. 9
·期 7
·2001136
·
IF 3.631
Yang Gui,Pengcheng Li,Junsong Chen,Baoan Fan,Daniel John Blackwood
Recently, a multicomponent system in the electrochemical energy-storage field exhibits advantages of both electrochemical activity and electronic conductivity due to its synergistic effects. Herein, a trimetallic oxide thin film of Ni−Mn−Fe is obtained through a facile cyclic voltammetric electrodeposition method. The obtained thin film is grown vertically on Ni substrate to form a unique nanosheet morphology with shear-wall structure. This less crystalline structure is beneficial for the observed faster kinetics due to the rational transport channels, avoiding sluggish charge diffusion. This trioxide thin film displays a maximum capacitance of 3950 F g −1 at a current density of 1 A g −1 , with 1250 F g −1 being obtained at a higher current density of 25 A g −1 and maintaining a capacitance of 865 F g −1 after 10 000 cycles. In addition, by paring this film as a cathode with activated carbon, it delivers a considerable energy density of 194.2 Wh kg −1 at a power density of 0.75 kW kg −1 and still outputs an energy density of 33.2 Wh kg −1 at its highest power density of 19 kW kg −1 . When applied to a practical condition, the cell lights up three red light-emitting diodes (LEDs).
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
ChemistrySelect
·
2022
·Vol. 7
·期 45
·e202203943
·
IF 2.307
Jie Zhu,Feng Lin,Yuelan Zhang,Jianghao Wang,Jie Fu,Pingkai Ouyang
Graphical A Mn, Fe co-doped Ni(OH) x catalyst with high-density nanoparticle-nanosheet structure was prepared for industrial-level OER application. Mn and Fe can modulate the electronic structure of nickel hydroxide, and the high-density nanoparticle-nanosheet array structure can minimize the bubble adhesion effect. These features are conducive to improving OER activity. Oxygen evolution reaction (OER) plays key roles in the energy efficiency of electro-catalytic systems. However, the sluggish kinetics and accumulated gas slugs under the industrial operation condition limit the application of OER. Herein, Mn, Fe co-doped nickel hydroxide with highly dense nano-sheets array is obtained through a simple and mild two-step etching strategy, which exhibits a remarkable OER performance. Doping Mn and Fe can modulate the electronic structure and redox behavior of active site, leading to an excellent intrinsic activity toward OER. Moreover, highly dense nanoparticle-nanosheet array structure is conducive to provide more active sites and inhibit the accumulation of gas slugs under industrial current density. Thus, the obtained catalyst provides an impressing current density of 1.8 A cm −2 at a small overpotential of 370 mV and sustains the performance more than 100 h.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Haodong Zheng,Xiaoxiang Wang,Kaile Shi,Yidong Hu,Wenxuan Lv,Pengfei Yin,Chengze li,Libo Sun,Jingjing Wang,Boxiong Shen,Hui Liu
Electrochemical organic oxidation has shown great industrial potential due to its green, low-carbon, and energy-efficient advantages. However, the competing oxygen evolution reaction (OER) severely impacts the faradaic efficiency and conversion rate of organic oxidation reactions. In this work, we report a method that can promote the oxidation of 5-hydroxymethylfurfural (HMFOR) while suppressing the OER, which is achieved by etching NiMnFe-LDH with N,N-dimethylacetamide (DMF), resulting in the formation of numerous cationic defects. Specifically, at a current density of 50 mA cm–2, the applied potential for HMFOR decreased by 50 mV, while the OER potential increased by 30 mV. In situ electrochemical impedance spectroscopy found faster reaction kinetics for d-NiMnFe-layered double hydroxide (LDH) compared to that of NiMnFe-LDH in HMFOR, whereas an opposite trend was observed in the OER, confirming that the DMF treatment has opposite effects on the transportation of organic molecules and OH–. To further investigate the reaction pathways and evolution of intermediates during HMFOR, in situ infrared spectroscopy and theoretical calculations were conducted, which demonstrate that cationic defects not only significantly enhance the adsorption of intermediates but also lower the reaction energy barrier, thus accelerating the reaction rate of HMFOR. This work provides a potential strategy for developing industrial-grade electrocatalysts for high current densities.
研究领域:
电化学
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催化
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材料科学
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绿色化学
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能量转换
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表面工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）