JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Hongyu Ding,Yujie Yang,Hao Li,Zhenyu Zhang,Zhihao Geng
High-entropy alloys (HEAs) demonstrate exceptional potential as electromagnetic wave absorbers owing to their tunable electromagnetic properties and compositional adaptability. Here, we investigate FeCoNiCrX (X = Cu, Mn, Mo, Al, Y) high-entropy alloys synthesized by vacuum induction melting-gas atomization. The FeCoNiCrMn system shows optimal microwave absorption performance, achieving a minimum reflection loss (RL) of −37.39 dB at 16.32 GHz (5.5 mm thickness) and an effective absorption bandwidth (EAB < −10 dB) of 1.52 GHz (16.48–18 GHz) at 5 mm. Surface engineering through MgO incorporation (1.0 wt%) further improves impedance matching, yielding a composite with RL min = -35.13 dB at 13.76 GHz (2 mm thickness) and 84 % broader EAB (2.8 GHz, 13.52–16.32 GHz) compared to pristine HEAs. The enhancement results from optimized dielectric-magnetic coupling and interfacial polarization, providing a strategic approach for designing thickness-adaptive microwave absorbers.
研究领域:
材料科学
·
电磁波吸收
·
合金工程
·
微波技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yifan Yang,Mengyao Yang,Zhaohui Huang,Jizeng Zhao,Wei Zhao,Ding'ao Yang,Lin Ren,Xiantang Zhao,Hao Yan,Lei Liu,Lei Gong
With the increasing severity in the service environment of secondary refining furnaces, traditional refractories cannot meet the high requirements. MgO-based fired refractories are subject to the thermal shock effect and slag penetration which are detrimental to their performance. In this study, low-carbon MgO-based refractories are reinforced by an in-situ MgAl 2 O 4 (MA)-TiO 2 dense layer with the addition of low-cost self-prepared titanium carbonitride [Ti(C, N)]. The influence of the addition of as-prepared Ti(C, N) on the properties of low-carbon MgO-based refractories was investigated. The reinforced refractories had no cracks after 190 thermal shock cycles, demonstrating the highest hot modulus of rupture (HMOR) with excellent thermal shock resistance (TSR). After 2.5 h of rotary immersion in a steel slag, the corrosion depth of the composites was only 26.3% of that of commercial MgO-CaO refractories. Based on the thermodynamic analysis, the Ti(C, N) reinforcement mechanism for the low-carbon MgO-based refractories was studied. A MA-TiO 2 dense layer formed during the oxidation process of the composites which enhanced the oxidation resistance . The volume expansion caused by the partial oxidation of Ti(C, N) prevents the penetration of the molten slag to refractories and Ti(C, N) powders forming a protective layer to further effectively protect the composites from slag corrosion owing to its high surface area. In addition, 3CaO·2TiO 2 formed by the reaction between the steel slag and Ti(C, N) further increased the slag corrosion resistance (SCR) of the composites. This research offers a new idea for the material selection for secondary refining furnaces to achieve a green and effective steel-making production route and enriches the understanding of the phase behaviour in the Mg-Al-Ti-C-O-N system under high temperatures.
研究领域:
材料科学
·
冶金工程
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Hai Liang,Jianjiang Wang,Wanting Wang,Yingli Wang,Xinzhong Deng,Zhishuang Xue,Yang Sun,Gaohong He,Xuehua Ruan
Developing efficient biochar (BC) adsorbent for pollution removal has been a long-term exploration. However, the negative charge surface of pristine BC seriously impedes the transfer of anionic dye through the pore of BC and results in low adsorption capacity. Herein, N-doping enriched porous MgO-modified biochar (MBC) was successfully prepared through a facile nitrate activation method for anionic acid fuchsin (AF) removal. The N-doped group of secondary amine in MBC changes the surface charge of BC and facilitate the AF adsorption onto MgO . The as-prepared MBC exhibited superior adsorption capacity of 328 mg⋅g −1 . The adsorption process was well aligned with the Freundlich and pseudo-second-order kinetics models indicating a hybrid physicochemical adsorption mechanism. Further mechanism investigation indicates that N-doped group, MgO and functional groups in biochar matrix primarily contribute to AF adsorption. The mechanism includes: electrostatic attraction, π-π interaction, hydrogen bonding and pore filling. This research provides an environmentally friendly nitrate activation strategy for BC, which overcomes the inherent defects of BC in negative charge surface and provides a facile way of biomass valorization for pollution removal from the aquatic environment.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Huixia Li,Shaofan Fang,Junfang Ding,Shaoqing Chen,Liping Li,Guangshe Li
Active-sites play a pivotal role in catalyzing reactions at surfaces, yet engineering these active sites still remains a significant challenge. In this work, hydroxylated MgO nanosheets supported ultrasmall PtNi alloys approximately 2.6(1) nm ( x Pt- y Ni/MgO hydr ) has been investigated via active-site engineering. Experimental results and DFT calculations reveal that electron transfers from Ni to Pt and from hydroxyl groups to Pt 5d-orbitals generate active sites NiPt-(OH) x . In the preferential CO oxidation (CO-PROX) reaction, these active sites on x Pt- y Ni/MgO hydr switch the bicarbonates reaction pathway depending on temperature range. Consequently, the optimal catalyst, 5%Pt-0.5%Ni/MgO hydr , achieves 100% CO conversion at 100 °C, demonstrating a broad temperature operation window (100–200 °C) and excellent durability. The active site engineering approach presented in this study can promote the discovery of more excellent catalysts with the optimal reaction route for various applications.
研究领域:
催化化学
·
材料科学
·
表面科学
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产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Xinrui Huang,Jingsong Liu,Mengshi Zeng,Xiaowei Yang,Xiaojiang Liu
In this article, the MgO imporous fibers, MgO porous fibers and hydrofluoric acid (HF) modified MgO porous fibers were researched as the electrolyte binders in Li–Si/LiCl–KCl/FeS 2 thermal batteries respectively. The results show that the wettability between the LiCl–KCl molten salt and the MgO fiber binders increases significantly in order of MgO porous fibers and HF modified MgO porous fibers. The separator pellet using the MgO porous fiber modified by 40 mol% (of the MgO fiber) HF solution as the electrolyte binder exhibits an extremely small amount of electrolyte leakages (19.6 mg cm −2 ) and the highest ionic conductivity (0.66 S cm −1 at 450 °C). Meanwhile, the corresponding thermal battery shows the largest discharge capacity (425 mA h g −1 at 1.0 V voltage plateau). Moreover, the effect of HF modification on the ion migration was analyzed based on the analysis of element diffusion and the formed MgF 2 phase. In summary, modification of MgO porous fiber binder by HF solution is a potential way to improve the performance of thermal batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Advanced Materials Interfaces
·
2024
·
IF 4.3
Xiaoju Yue,Lin Han,Shifeng Wang,Linan Dun,Jinnong Wang,Yuanhao Wang,Chun Du
Degradation of organic pollutants in wastewater is crucial for global environmental health. Semiconductor-based photocatalytic technologies have received widespread attention due to their ability to directly utilize solar energy, produce no secondary pollution, and offer long-lasting functionality. However, current photocatalyst preparation technologies face issues such as complex manufacturing processes, low efficiency, and the need for various additives. Therefore, this work proposes a simple and eco-friendly method to in-situ growth of reduced graphene oxide (rGO) onto magnesium oxide (MgO), forming a MgO@rGO core-shell structured photocatalyst through CO 2 thermal reaction process. After systematic study, the incorporation of rGO onto MgO core greatly extends the light absorption range from ultraviolet (UV) to visible wavelength, enabling substantially enhanced light capture and photoexcited carriers. Additionally, the core-shell heterojunction with a built-in electric field at the interface between MgO and rGO facilitates distinctly the separation and migration of the photogenerated charges. This structure-induced synergistic effect boosts the photocatalytic performance of MgO@rGO by a factor of 1.7, 4.1, 41.8, and 6.4, compared with MgO (stripped), MgO (pure), rGO, and commercially used TiO 2 , respectively. This work provides a simple and effective strategy for designing advanced functional nanocomposites to address environmental problems.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materiomics
·
2020
·
IF 5.797
Chi Zhang,Ying Chen,Xin Li,Haishen Ren,Genshui Wang,Xianlin Dong
Glass-free MgO-based microwave dielectric ceramics (1-x) wt% (0.98 MgO-0.02 Al 2 O 3 )-x wt% LiF (x = 0.5, 1, 2, 3, 4) were synthesized where LiF and Al 2 O 3 were utilized as sintering additive and reinforcement phase in MgO matrix respectively. It was found that ion substitution is apt to occur between LiF and MgO, leading to the formation of oxygen vacancies and MgF 2 . Nevertheless, different from ordinary liquid-phase sintering, morphologies of ceramics were distinctly altered with grains changing from polyhedron to sphere-like shape and densities underwent obvious decrease when excessive amount of LiF was introduced and we call it excessive liquid-phase sintering. Grain boundary weakening caused by this circumstance would exert an adverse effect on physical properties. Moreover, LiF addition dramatically reduced dielectric breakdown strength and altered the dielectric breakdown behavior of MgO-based ceramics, which is dominated by electrical breakdown mechanism. Combination of good properties were achieved in 1 wt% LiF modified MgO-based ceramics sintered at 950 °C which exhibited superior microwave properties (ε r = 9.56, tanδ = 9.2 × 10 −5 , Qf = 124,600 GHz), high flexural strength (184.5 MPa), high thermal conductivity (21.3 W/(m⋅K)), high coefficient of thermal expansion (∼12 ppm/°C) and moderate electrical properties (E b = 35.9 kV/mm, ρ = 4.9 × 10 12 Ω cm).
研究领域:
材料科学
·
电子材料
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产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2022
·
IF 11.322
Zizhang Zhan,Wei Sun,Shuaishuai Zhang,Qingbo Wen,Hongbo Zhang,Xiang Xiong
A (AlCrMg) x (PO 4 ) y /MgO composite(APMC) was prepared based on the acid–base reaction between MgO and chromium aluminum phosphate solution for thermal protection and insulation applications at ultrahigh-temperatures up to 2400 °C. The compositions, formation mechanisms, microstructure, mechanical properties , thermal conductivity and ablation resistance of the composite were systematically investigated. The results show that the (AlCrMg) x (PO 4 ) y /MgO composite can be consolidated in different shapes at room temperature. The compressive strength of the as-prepared porous composites is higher than 20 MPa due to the macromolecular network structure, and it can be further improved to 42 MPa via thermal treatment. After ablation by an oxyacetylene flame at 2400 ± 70 °C for 60 s, the mass and line ablation rates of the composite were 0.0195 g/s and 0.43 × 10 −3 mm/s, respectively, which are comparable to those of ultrahigh-temperature ceramics. The excellent ablation resistance can be attributed to the in situ formation of a dense protective layer composed of spinel MgCr 2 O 4 and MgO phases. Interestingly, during ablation at 2400 °C the back-side temperature of the 15 mm-thick sample was lower than 130 °C, suggesting outstanding thermal insulation performance. The temperature gradient leads to the formation of a gradated porous structure which reduces the overall thermal conductivity of the composite.
研究领域:
材料科学
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航空航天工程
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产品关联
DOI
高影响因子
Environmental Science-Nano
·
2021
·Vol. 8
·期 9
·2569-2583
·
IF 8.131
Siyang Li,Shujuan Zhan,Jingxiang Sun,Lingai Yao,Jinzhu Zhu,Jinxi Feng,Ya Xiong,Shuanghong Tian
Highly reactive nanoclusters of metal oxides are extremely difficult to synthesize due to their thermodynamic instability. For the first time, MgO nanoclusters supported on sewage sludge-derived hierarchical porous carbon (MgO nanoclusters/SC) were successfully prepared by grafting 1.31 ± 0.03 mmol g−1 acidic groups on the SC, then dynamically controlling the chemisorption of Mg2+ on the modified SC within 20 s, and finally transforming the fixed Mg2+ into MgO nanoclusters with a size of less than 2.4 nm via thermal treatment. Moreover, the cluster size could be facilely tailored by controlling the dynamic adsorption time and initial aqueous Mg2+ concentration. The resulting five MgO nanoclusters/SC-20 s samples with 0.43–1.12% (mass percentage) Mg have a turnover frequency of 0.038 towards the catalytic ozonation of 4-chlorophenol, much higher than those of the bigger nanoclusters and nanocrystals (i.e. MgO/SC-20 s with 1.43% Mg, MgO/SC-3 min with 0.85–2.0% Mg). The pseudo-first-order reaction constant of MgO nanoclusters/SC with 1.12% Mg is 0.0126 min−1, 6.0 and 4.1 times that of SC and bulky MgO/SC, respectively. The presence of MgO nanoclusters/SC also enhanced the removal of cephalexin, florfenicol and sulfamethoxazole by 54.3%, 45.5%, and 57.4%, respectively. The high activity can be ascribed to the rich and highly under-coordinated Mg in the smaller MgO nanoclusters and the unblocked hierarchical pores of the SC support. Finally, DFT calculations revealed at the atomic level that the under-coordinated Mg in MgO nanoclusters could directly or indirectly activate ozone through the protonated hydroxyl or just hydroxyl bonded to the under-coordinated Mg. Except for (MgO)2, the smaller the nanocluster, the higher the activity. This work shed a light on the design and preparation of highly reactive nanoclusters of metal oxide catalysts for catalytic ozonation of refractory organic pollutants.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Qi Yuan,Sen Wang,Gaobin Liu,Kuoming Song,He Zhao,Shuai Yan,Xin Li
Dense MgO–12% TiO 2 (w) ceramics containing 12 wt% TiO 2 , which were doped with Li 2 CO 3 –Bi 2 O 3 composite sintering aids, were prepared at a low sintering temperature of 950 °C in this study. The effects of sintering additives on the sintering characteristics, phase composition, microstructure, and dielectric and mechanical properties of the ceramic samples were systematically investigated, and the influences of their phase composition and microstructure on the dielectric and mechanical properties were examined. The introduction of sintering aids produced a new Bi 4 Ti 3 O 12 phase in the sample structure, while the residual Bi 2 O 3 mixed with the newly formed Mg 2 TiO 4 and Bi 4 Ti 3 O 12 phases distributed at MgO grain boundaries formed a structure surrounding MgO grains. This structure filled the pores in the ceramic sample, which increased its density and enhanced the mechanical properties. At a Li 2 CO 3 –Bi 2 O 3 content of 15 wt%, the density, flexural strength , and Vickers hardness of the ceramic samples reached their maximum values of 3.4 g/cm 3 , 218.9 MPa, and 778.7 HV, respectively. However, the further increase in the Li 2 CO 3 –Bi 2 O 3 content deteriorated their dielectric properties although the dielectric constant and dielectric loss remained below 13.4 and 2.1 × 10 −3 , respectively. The findings of this work indicate that Li 2 CO 3 –Bi 2 O 3 sintering aids can significantly lower the sintering temperature of MgO–12% TiO 2 (w) ceramics and control their dielectric and mechanical properties through microstructural changes.
研究领域:
材料科学
·
陶瓷
·
介电学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 85
·54068-54077
·
IF 3.108
Wenhan Chen,Qi Luo,Xueshuang Deng,Jianfeng Zheng,Chenxi Zhang,Xiaohong Chen,Sumei Huang
The morphology of electron transport layers has a significant impact on the device architecture and electronic processes of mesoscopic perovskite solar cells (PSCs). In this study, ultrathin MgO is coated on the surface of compact TiO2 (c-TiO2). The MgO-coated c-TiO2 is first used as seeds to hydrothermally grow one-dimensional (1D) TiO2 nanorod (NR) arrays for PSC devices. Rutile nanorod arrays are fabricated via a facile solvothermal method using tetrabutyl titanate (TBT) as the Ti precursor. The microstructures and morphologies, including nanorod diameter, length, and areal density, of the TiO2 NR arrays are varied by controlling the concentration of TBT from 0.3 M to 0.7 M. Furthermore, the profound effects of the MgO modification and titania nanorod morphology on the pore-filling of perovskite CH3NH3PbI3, charge separation and recombination at the perovskite/titania nanorod interface are investigated. Our results reveal that the Ti precursor concentration strongly affects the open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF) of the 1D TiO2 NR array-based device. Under optimized conditions with MgO coating and at 0.4 M TBT, our champion cell with 1D TiO2 NRs demonstrates a power conversion efficiency (PCE) of 17.03% with JSC = 22.01 mA cm−2, VOC = 1.06 V, and FF = 0.73. Under the same fabrication conditions, MgO modification enhances the average PCE to 16.24% for the PSCs with the MgO coating from 13.38% for the PSCs without the MgO coating. The devices show an approximately 18% improvement in performance, which mainly results from the open-circuit voltage and fill factor enhancements. Moreover, advantageously, the MgO modification is found to reduce the current density–voltage (J–V) hysteresis with respect to the scan direction and improve the UV stability of the non-encapsulated cells. Therefore, this study presents a promising approach to fabricate efficient and stable one-dimensional TiO2 nanorod array-based perovskite solar cells.
研究领域:
材料科学
·
光电子学
·
能源研究
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xufeng Zhang,Huidan Zeng,Xin Wang,Weichang Li,Lili Hu,Shubin Chen
MgO–Al 2 O 3 –SiO 2 glass-ceramics have been widely used in military, industrial, and construction applications. The nucleating agent is one of the most important factors in the production of glass-ceramics as it can control the crystallization temperature or the grain size. In this study, we investigated the effect of replacing P 2 O 5 with different amounts of TiO 2 on the crystallization, structure, and mechanical properties of an MgO–Al 2 O 3 –SiO 2 system. The crystallization and microstructure were investigated by differential scanning calorimetry , Raman spectroscopy , X-ray diffraction, scanning electron microscopy, and transmission electron microscopy . The mechanical properties were investigated by measuring the Vickers hardness , Young's modulus , and fracture toughness. The results showed that adding TiO 2 favored the precipitation of fine grains and significantly increased the Vickers hardness, Young's modulus, and fracture toughness of the glasses. Introducing an appropriate amount of TiO 2 can make a glass structure more compact, promote crystallization, and improve the mechanical properties of MgO–Al 2 O 3 –SiO 2 glass-ceramics.
研究领域:
材料科学
·
陶瓷学
·
玻璃科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）