Materials Today Physics最新文献_第4页

Intelligent hybrid hydrogel with nanoarchitectonics for water harvesting from acidic fog 利用纳米结构的智能混合水凝胶从酸雾中收集水分

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-21 DOI: 10.1016/j.mtphys.2024.101574

Wenle Pei, Xiaoliang Pei, Zhuangzhuang Xie, Shaoheng Liu, Jianmei Wang

With the development of society, the demand for water resources has risen has increased sharply, and water shortage is becoming a huge challenge to mankind. Therefore, it is extremely urgent to develop a convenient, low-cost, and environmentally friendly fog harvesting material. In this work, inspired by lotus stem with efficient water transport characteristics, the intelligent hybrid hydrogel (IHH) synergistically combines the characteristics of the pH-sensitive PDMAEMA polymer chain and thermo-switchable PNIPAM polymer chain, which simultaneously realizes superior efficient acidic fog uptake (∼6.5 g/g), high-density acidic fog storage, ultra-fast clean water releasing in the efficiency of ∼90 % for 12 min at 60 °C and high cycling stability (∼25 cycles). It is mainly attributed that the amine groups of the PDMAEMA chains are protonated under acidic state, and further the hydration is enhanced, and thus resulting the hydrogel to absorb the acid fog and swell. The PNIPAM polymer can achieve a rapidly reversible phase transition from a hydrophilic state to a hydrophobic one when the temperature beyond LCST, achieving the water releasing quickly. This IHH achieves preliminary water purification, which converts the harvested acidic fog into clean water as the freshwater generator. The IHH offers an insight into the design of novel materials that serve as the freshwater generator in complex environments of practical applications such as fog harvesting devices or systems.

随着社会的发展，人们对水资源的需求急剧增加，水资源短缺正成为人类面临的巨大挑战。因此，开发一种方便快捷、成本低廉、环境友好的集雾材料显得尤为迫切。本研究从具有高效输水特性的荷花茎中汲取灵感，将 pH 敏感的 PDMAEMA 聚合物链和热切换的 PNIPAM 聚合物链的特性协同结合，开发出智能杂化水凝胶（IHH），同时实现了优越的高效酸性雾吸收（∼6.5 g/g）、高密度酸性雾存储、超快速洁净水释放（60°C 下 12 分钟释放效率∼90%）和高循环稳定性（∼25 次循环）。这主要是因为 PDMAEMA 链上的胺基团在酸性状态下质子化，进一步增强了水合作用，从而导致水凝胶吸收酸雾并膨胀。当温度超过 LCST 时，PNIPAM 聚合物可实现从亲水态到疏水态的快速可逆相变，从而达到快速释水的目的。这种 IHH 实现了初步的水净化，将收获的酸性雾转化为清洁水，作为淡水生成器。IHH 为设计新型材料提供了启示，这些材料可在雾收集装置或系统等实际应用的复杂环境中用作淡水发生器。

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引用次数: 0

Synergistic effect of lone-pair electron and atomic distortion in introducing anomalous phonon transport in layered PbXSeF (X= Cu, Ag) compounds with low lattice thermal conductivity 孤对电子和原子畸变在具有低晶格热导率的层状 PbXSeF（X= 铜、银）化合物中引入反常声子输运的协同效应

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-18 DOI: 10.1016/j.mtphys.2024.101572

Peng Ai , Shuwei Tang , Da Wan , Wanrong Guo , Hao Wang , Pengfei Zhang , Tuo Zheng , Shulin Bai

Using first-principles calculations, self-consistent phonon theory and Boltzmann transport theory, the crystal structure, phonon and electronic transport, and thermoelectric (TE) properties of PbXSeF (X = Cu, Ag) compounds are comprehensive explored in the current work. The heterogeneous bonding characteristics along the in-plane and out-of-plane directions lead to low lattice thermal conductivities in PbXSeF (X = Cu, Ag) compounds. The low lattice thermal conductivity is primarily attributed to strong anharmonicity caused by the lone-pair electrons of Pb. Notably, the PbCuSeF compound, despite the lighter mass in comparison with PbAgSeF, exhibits relatively lower lattice thermal conductivity. Such finding can be attributed to the distortion introduced by Cu atom, which leads to strong quartic anharmonicity, and thereby suppressing the heat-carrying phonons through the rattling-like behavior of Cu atom. The lone-pair electrons of Pb²⁺ and the heterogeneous bonding characteristics in PbXSeF (X = Cu, Ag) compounds contribute the multi-valley band degeneracy, resulting the decoupling of Seebeck coefficient and electrical conductivity with carrier concentration while generating in a high power factor. Our current work not only illustrates the fundamental insights into the low lattice thermal conductivity and related anomaly of layered PbXSeF (X = Cu, Ag) compounds based on the four-phonon scattering and multiple carrier scattering rates, but also highlights the anisotropic feature of electronic and thermal transport properties.

本研究利用第一原理计算、自洽声子理论和玻尔兹曼输运理论，全面探讨了 PbXSeF（X = 铜、银）化合物的晶体结构、声子和电子输运以及热电（TE）特性。面内和面外方向的异质成键特性导致 PbXSeF (X = Cu, Ag) 复合物具有较低的晶格热导率。进一步的评估表明，超低晶格热导率主要归因于 Pb2+ 原子的单对电子引起的强非谐性。值得注意的是，尽管 PbCuSeF 复合物的质量比 PbAgSeF 轻，但其晶格热导率却相对较低。这一发现可归因于铜原子引入的畸变，畸变导致了强烈的四次方非谐波，从而通过铜原子的类似振荡行为抑制了载热声子。在 PbXSeF（X = Cu、Ag）化合物中，铅原子的孤对电子和异质成键特性导致了多谷带退化，从而使塞贝克系数和电导率与载流子浓度脱钩，同时产生高功率因数。我们目前的研究工作不仅基于四声子散射和多载流子散射率，从根本上揭示了层状 PbXSeF（X = 铜、银）化合物的低晶格热导率和相关异常现象，而且突出了电子和热传输特性的各向异性特征。

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引用次数: 0

Rational design of MnCoGe alloys for enhanced magnetocaloric performance and reduced thermal hysteresis 合理设计锰钴锗合金以提高磁致性能并减少热滞后

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-18 DOI: 10.1016/j.mtphys.2024.101573

Rongcheng Li , Chenghao Xie , Yicheng Wang , Bowen Jin , Jiushun Zhu , Xinfeng Tang , Gangjian Tan

MnCoGe alloys are widely recognized as an important family of rare-earth-free magnetocaloric materials by engineering its magnetostructural coupling for giant entropy changes. However, its practicability for magnetic refrigeration is largely hindered by the large thermal hysteresis. In this work, we show that the co-doped MnCoGe compound, namely Mn_0.95Cu_0.03CoGe with 2 both mol% Mn vacancies and 3 mol% Cu-doping for Mn, displays a maximum entropy change of 29.0 J kg⁻¹K⁻¹ at 295 K under a magnetic field of 5 T, together with a relative cooling power as high as 314.5 J kg⁻¹ and a record low thermal hysteresis of 16 K. The co-doping strategy in MnCoGe finely tunes the structural transition temperature within the range of Curie temperature window, leading to a strong magnetostructural coupling and giant magnetocaloric effect. Meanwhile, Mn-deficiency and Cu-doping considerably reduce the energy difference between martensitic and austenitic MnCoGe, rendering a minimal thermal hysteresis. Our co-doped MnCoGe alloys are robust candidates for near-room-temperature magnetic refrigeration.

钴锗锰合金通过磁结构耦合作用产生巨大的熵变，被广泛认为是重要的无稀土磁致冷材料系列。然而，它在磁制冷方面的实用性在很大程度上受到大热滞后的阻碍。在这项研究中，我们发现共掺杂的 MnCoGe 化合物（即 Mn0.95Cu0.03CoGe，锰空位为 2 mol%，掺杂铜的锰含量为 3 mol%）在 5 T 的磁场下于 295 K 时的最大熵变为 29.0 J kg-1K-1，相对制冷功率高达 314.锰钴锗中的共掺杂策略在居里温度窗口范围内对结构转变温度进行了微调，从而产生了强大的磁结构耦合和巨大的磁致效应。同时，缺锰和掺铜大大降低了马氏体和奥氏体锰钴锗之间的能量差，使热滞最小。我们的共掺杂锰钴锗合金是近室温磁制冷的可靠候选材料。

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引用次数: 0

Superior bendability enabled by inherent in-plane elasticity in Bi2Te3 thermoelectrics 利用 Bi2Te3 热电材料固有的面内弹性实现卓越的可弯曲性

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-16 DOI: 10.1016/j.mtphys.2024.101570

Yixin Hu , Xinyi Shen , Zhiwei Chen, Min Liu, Xinyue Zhang, Long Yang, Jun Luo, Wen Li, Yanzhong Pei

With the rapid development of modern wearable electronics, powerful and deformable thermoelectric generators have become an urgent need as the power units that convert environmental or body heat into electricity. Existing efforts mostly focused on the assistance for deformability by substrates/additives, the resultant devices usually output much less power and showed very poor power retainment. Elasticity is inherent to all solids, which therefore offers an intrinsic solution for making thermoelectrics deformable without compromise in power output because of its full recoverability. This work demonstrates this in best-performing (Bi, Sb)₂(Te, Se)₃ thermoelectrics near room temperature, ending up in the film devices with both extraordinary power density and robust recoverable bendability. This originates from the inherent large elasticity for the in-plane orientation, which is enabled by an easy tape stripping approach for the Van der Waals layered structure, allowing the realization of both powerfulness and bendability that are equally important for wearable thermoelectrics.

随着现代可穿戴电子设备的快速发展，迫切需要功能强大、可变形的热电发生器作为将环境或人体热量转化为电能的动力装置。现有的努力大多集中在通过基材/添加剂来帮助实现可变形性，由此产生的设备通常输出的功率要小得多，而且功率保持能力非常差。弹性是所有固体所固有的，因此，它提供了一个内在的解决方案，使热电半导体器件具有可变形性，并且由于其完全可恢复性而不会影响功率输出。这项工作在室温附近性能最佳的 (Bi，Sb)2(Te，Se)3 热电半导体中证明了这一点，最终薄膜设备具有超高功率密度和强大的可恢复弯曲性。这源于面内取向的固有大弹性，而范德华层状结构的简易胶带剥离方法使这种弹性成为可能，从而实现了对可穿戴热电设备同样重要的功率密度和可弯曲性。

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引用次数: 0

Building TiO2-Ti3C2Tx heterojunction by microwave-assisted hydrothermal as an amphiphilic nanoreactor for high-performance lithium sulfur batteries 通过微波辅助水热法构建 TiO2-Ti3C2Tx 异质结，作为高性能锂硫电池的两性纳米反应器

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-16 DOI: 10.1016/j.mtphys.2024.101571

Yu Jiang , Rong Yang , Lei Mao , Guozhuang Gao , Chaojiang Fan , Bailing Jiang , Haochen Liu , Yinglin Yan

The adoption of lithium-sulfur (Li-S) batteries faces significant obstacles due to the notorious lithium polysulfides (LiPSs) shuttle effect and sluggish electrochemical reaction kinetics. To tackle these issues, MXene, with the unique layered structures and metal centers, have emerged as promising additives in Li-S batteries, effectively hindering the migration of polysulfides through physical and chemical confinement mechanisms. However, MXenes inherently lack robust anchoring sites for LiPSs, leading to suboptimal cycle stability. Here, TiO₂-Ti₃C₂T_x (TT) heterojunction derived from MXene is constructed by the microwave-assisted hydrothermal (MAH). This innovative TT composite incorporates an amphiphilic nanoreactor that synergistically adsorbs, catalyzes LiPSs, and stabilizes the lithium anode in Li-S batteries. The optimally exposed surface of Ti₃C₂T_x and nano-sized TiO₂ within the TT architecture collaborate to “conduct, adsorb and transform” LiPSs, while the heterogeneous interface and crumpled sheets provide an efficient three-dimensional transport pathway for Li⁺ in the electrolyte, collaboratively enhancing the stability of Li-S batteries. Therefore, the TT-160 as an interlayer for Li-S battery exhibits an ultra-low capacity attenuation of each cycle of 0.022 % after 1000 cycles at 2 C. Furthermore, the conductive interlayer facilitates a uniform distribution of Li⁺ transport, enabling a Li//Li symmetric cell assembled with TT-160 to achieve remarkable stability over 1000 h. This work pioneeringly demonstrates the potential of MXene-derived TiO₂-Ti₃C₂T_x heterojunction, synthesized via MAH for high-performance Li-S batteries, opening up new avenues for material design and optimization.

由于众所周知的锂多硫化物（LiPSs）穿梭效应和缓慢的电化学反应动力学，锂硫（Li-S）电池的应用面临着巨大障碍。为了解决这些问题，具有独特层状结构和金属中心的 MXene 已成为锂-S 电池中很有前景的添加剂，它通过物理和化学限制机制有效地阻碍了多硫化物的迁移。然而，MXenes 本身缺乏锂多硫化物的稳固锚定位点，导致循环稳定性不理想。本文通过微波辅助水热法（MAH）构建了源自 MXene 的 TiO2-Ti3C2Tx（TT）异质结。这种创新的 TT 复合材料结合了一种两亲性纳米反应器，可协同吸附、催化锂离子电池并稳定锂离子电池中的锂阳极。在 TT 结构中，Ti3C2Tx 的最佳暴露表面和纳米尺寸的 TiO2 可协同 "传导、吸附和转化 "锂离子，而异质界面和皱褶片则为电解液中的 Li+ 提供了有效的三维传输途径，从而共同提高了锂离子电池的稳定性。因此，TT-160 作为锂-S 电池的中间膜，在 2 C 条件下循环 1000 次后，每次循环的容量衰减仅为 0.022%，具有超低的容量衰减。此外，导电中间膜促进了 Li+ 传输的均匀分布，使得使用 TT-160 组装的锂/锂对称电池在 1000 小时内具有出色的稳定性。这项工作开创性地证明了通过 MAH 合成的 MXene 衍生 TiO2-Ti3C2Tx 异质结在高性能锂-S 电池方面的潜力，为材料设计和优化开辟了新的途径。

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引用次数: 0

Revealing interfacial degradation of Bi2Te3-based micro thermoelectric device under current shocks 揭示电流冲击下基于 Bi2Te3 的微型热电器件的界面降解现象

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-11 DOI: 10.1016/j.mtphys.2024.101569

Jianan Lyu , Dongwang Yang , Mingqi Zhang , Yutian Liu , Ziao Wang , Zinan Zhang , Gang Zhan , Chenyang Li , Yuting Wang , Weijie Gou , Yunfei Gao , Chengyu Li , Jinsong Wu , Xinfeng Tang , Yonggao Yan

Micro thermoelectric devices (micro-TEDs) offer great potential for IoT and electronic thermal management. However, they face challenges with reliability under high current densities. This study elucidates the failure mechanisms of Bi₂Te₃-based micro-TEDs subjected to current shocks. Experimental results indicate that at a high current density of 1800 A/cm², the internal resistance of micro-TEDs increased by 12.9 % to 2.034 Ω. This led to a 52.0 % decrease in maximum output power at a 20 K temperature difference, dropping to 1.53 mW. Additionally, as the frequency of ON/OFF current applied to micro-TED increases, the resistance growth rate jumped from 0.764 mΩ/h for slow power cycling to 2.328 mΩ/h for fast power cycling. This indicates that higher cycling frequencies exacerbate the degradation of the device. In-situ TEM analysis revealed that current-induced elemental diffusion and electrical stress release led to the formation of NiTe₂ nanoparticles and intergranular fractures within the Bi₂Te₃ materials. These results indicate that interfacial degradation and subsequent grain delamination are primary causes to micro-TED failure under current shocks. These findings underscore the significance of considering electrical stress in micro-TED design to enhance reliability and performance for high-power applications.

微型热电器件（micro-TED）为物联网和电子热管理提供了巨大的潜力。然而，它们在高电流密度下的可靠性面临挑战。本研究阐明了基于 Bi2Te3 的微型热电器件在电流冲击下的失效机制。实验结果表明，在 1800 A/cm2 的高电流密度下，micro-TED 的内阻增加了 12.9% 至 2.034 Ω。此外，随着施加到 micro-TED 的导通/关断电流频率的增加，电阻增长率从慢速功率循环时的 0.764 mΩ/h 跃升到快速功率循环时的 2.328 mΩ/h。这表明更高的循环频率会加剧器件的降解。原位 TEM 分析表明，电流引起的元素扩散和电应力释放导致 Bi2Te3 材料内部形成 NiTe2 纳米颗粒和晶间裂缝。这些结果表明，界面降解和随后的晶粒分层是电流冲击下微 TED 失效的主要原因。这些发现强调了在微型 TED 设计中考虑电应力对提高大功率应用的可靠性和性能的重要意义。

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引用次数: 0

Effect of magnetic entropy in the thermoelectric properties of Fe-doped Fe2VAl full-Heusler alloy 磁熵对掺铁的 Fe2VAl 全赫斯勒合金热电性能的影响

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-11 DOI: 10.1016/j.mtphys.2024.101568

Tarachand , N. Tsujii , F. Garmroudi , E. Bauer , T. Mori

The effect of spin entropy on the transport of heat/charge carriers in the Fe-doped full-Heusler alloy Fe_2+xVAl_1-x with x = 0–0.1 has been studied through low-temperature magnetic and thermoelectric measurements. Magnetization (M) measurements confirm itinerant-electron weak-ferromagnetic behavior. A systematic increase of the magnetic transition temperature T_C (from 40 K to 223 K) and of the saturation magnetization (from 0.13 to 0.41μ_B/Fe) with increasing Fe doping (from x = 0 to 0.1) is observed. Applying a magnetic field causes significant suppression of the Seebeck coefficient (S) and the entropy term (S/T) with a negative magnetoresistance near T_C for all weak-ferromagnetic samples, demonstrating a clear effect of spin fluctuations. Analyzing M(T) and S(T), we rule out sizeable magnon drag contributions. A large spin fluctuations-induced enhancement in the thermoelectric power factor PF of about 18 % is achieved for x = 0.1 near T_C when compared to measurements in a magnetic field of 7 T. The actual improvement in PF is even much higher, as the S shows a significant enhancement (about 34 %) compared to the estimated diffusion term of S(T) at T_C. The number of point defects also increases with Fe doping, causing a significant reduction of the lattice thermal conductivity. This study demonstrates the role of spin fluctuations in enhancing the thermopower/thermoelectric performance of Fe-doped Fe₂VAl and opens a vista for the strategy's applicability for various thermoelectric materials.

通过低温磁性和热电测量，研究了自旋熵对 x = 0 - 0.1 的掺铁全赫斯勒合金 Fe2+xVAl1-x 中热/电荷载流子传输的影响。磁化（M）测量证实了巡回电子弱铁磁行为。随着铁掺杂量的增加（从 x = 0 到 0.1），磁转变温度 TC（从 40 K 到 223 K）和饱和磁化率（从 0.13 到 0.41μB/Fe）出现了系统性增长。对于所有弱铁磁性样品，施加磁场会显著抑制塞贝克系数（S）和熵项（S/T），并在 TC 附近产生负磁阻，这表明自旋波动具有明显的影响。通过分析 M(T) 和 S(T)，我们排除了可观的磁子阻力贡献。与 7 T 磁场中的测量结果相比，x = 0.1 时 TC 附近的热电功率因数 PF 在自旋波动的诱导下大幅提高了约 18%。由于 S 在 TC 时比估计的 S(T) 扩散项有显著提高（约 34%），PF 的实际提高幅度甚至更大。点缺陷的数量也随着铁的掺杂而增加，导致晶格热导率显著降低。这项研究证明了自旋波动在提高掺铁 Fe2VAl 的热功率/热电性能中的作用，并为该策略在各种热电材料中的应用开辟了前景。

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引用次数: 0

Wrinkled layers lead to high in-plane zT values in hexagonal CaAgSb 皱褶层导致六方 CaAgSb 具有较高的面内 zT 值

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-10 DOI: 10.1016/j.mtphys.2024.101566

Juan Cui , Chengliang Xia , Huan Zheng , Miao Zheng , Dafang Li , Yue Chen , Yu Yang

Layered thermoelectric materials (LTMs) have attracted great attention due to their anisotropic transport behaviors that provide an opportunity to disentangle the interrelated electrical and thermal conductivities. In this study, we found that hexagonal CaAgSb (h-CaAgSb) possesses a lower lattice thermal conductivity and a higher electrical conductivity simultaneously along the in-plane direction when compared with the out-of-plane direction. The low in-plane lattice thermal conductivity mainly originates from the low group velocity of longitudinal acoustic phonon modes. Meanwhile, strong anharmonicity is discovered for the low-lying optical phonon modes. On the other hand, the high in-plane electrical conductivity relies on the small effective mass. Thus, both p-type and n-type h-CaAgSb exhibit a high zT over 2.0 along the in-plane direction at the optimal carrier concentrations. The anisotropic transport properties of h-CaAgSb reported in this work may provide guidance to the experiments. More importantly, the physical insights revealed for the disentangled electrical and thermal transport properties may pave the way for finding other excellent LTMs and optimizing the thermoelectric performance through structure engineering.

层状热电材料（LTMs）因其各向异性的输运行为而备受关注，这为我们解开相互关联的电导率和热导率提供了机会。在这项研究中，我们发现六方 CaAgSb（h-CaAgSb）与面外方向相比，在面内方向同时具有较低的晶格热导率和较高的电导率。面内晶格热导率低的主要原因是纵向声子模式的群速度较低。同时，还发现低洼光学声子模式具有很强的非谐波性。另一方面，高面内电导率依赖于较小的有效质量。因此，在最佳载流子浓度下，p 型和 n 型 h-CaAgSb 沿面内方向都表现出超过 2.0 的高 zT。这项工作中报告的 h-CaAgSb 各向异性输运特性可为实验提供指导。更重要的是，本文所揭示的电学和热学输运特性相分离的物理原理，可为寻找其他优异的低温金属和通过结构工程优化热电性能铺平道路。

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引用次数: 0

Cu−based bimetallic sites' p-d orbital hybridization promotes CO asymmetric coupling conversion to C2 products 铜基双金属位点的 p-d 轨道杂化促进 CO 不对称耦合转化为 C2 产物

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-10 DOI: 10.1016/j.mtphys.2024.101565

Jiayong Xiao , Jofrey J. Masana , Ming Qiu , Ying Yu

Hampered by sluggish C−C coupling kinetics, the low selectivity and efficiency have limited industrial applications of CO₂ reduction into valuable multi-carbon products. A direct coupling of CO molecules or their coupling after hydrogenation, followed by the final synthesis of C₂ products, can help to overcome these limitations potentially. In this study, a detailed high-throughput screening of bimetallic site catalysts comprising copper (Cu) and 28 other metal (M) atoms was conducted. The metal atoms Cu and M were anchored on a carbon nanotube (CNT) with six nitrogen (N₆) defects (CuMN₆@CNT), which possesses effective dual active sites for C−C coupling. The calculated results demonstrate that the CuGaN₆@CNT catalyst exhibited favorable selectivity, with low theoretical overpotentials of −0.23 and −0.34 eV for ethanol and ethylene, respectively, surpassing most reported catalysts. The synergistic effect of Ga and Cu sites, along with their p-d states hybridization, results in an enhancement of Cu's d state dispersion and energy barriers reduction for C−C coupling. Additionally, the strain effect of the substrate CNT exhibits a direct correlation with the catalytic performance of CuGaN₆@CNT by adjusting the d-band center of the Cu site and p-band center of the Ga site. These findings provide a novel insights into the electrocatalytic reduction of CO into valuable C₂ products using bimetallic single atom catalyst, offering significant guidance for future research endeavors in this field.

由于 C-C 偶联动力学缓慢，选择性和效率较低，限制了将 CO2 还原成有价值的多碳产品的工业应用。直接耦合 CO 分子或在氢化后耦合 CO 分子，然后最终合成 C2 产物，有助于克服这些潜在的局限性。本研究对由铜（Cu）原子和 28 个其他金属（M）原子组成的双金属位点催化剂进行了详细的高通量筛选。金属原子 Cu 和 M 被锚定在具有六个氮（N6）缺陷的碳纳米管（CNT）上（CuMN6@CNT），该碳纳米管具有 C-C 偶联的有效双活性位点。计算结果表明，CuGaN6@CNT 催化剂具有良好的选择性，对乙醇和乙烯的理论过电位分别为 -0.23 和 -0.34 eV，低于大多数已报道的催化剂。Ga 和 Cu 位点的协同效应以及它们的 p-d 态杂化作用增强了 Cu 的 d 态分散性，降低了 C-C 耦合的能垒。此外，通过调整铜位点的 d 波段中心和镓位点的 p 波段中心，基底 CNT 的应变效应与 CuGaN6@CNT 的催化性能直接相关。这些发现为利用双金属单原子催化剂电催化将 CO 还原成有价值的 C2 产物提供了新的见解，为该领域未来的研究工作提供了重要指导。

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引用次数: 0

CoFe2O4-BaTiO3 core-shell-embedded flexible polymer composite as an efficient magnetoelectric energy harvester 作为高效磁电能量收集器的 CoFe2O4-BaTiO3 芯壳嵌入式柔性聚合物复合材料

IF 1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2024-10-10 DOI: 10.1016/j.mtphys.2024.101567

Bitna Bae , Nagamalleswara Rao Alluri , Cheol Min Kim , Jungho Ryu , Gwang Hyeon Kim , Hyeon Jun Park , Changyeon Baek , Min-Ku Lee , Gyoung-Ja Lee , Geon-Tae Hwang , Kwi-Il Park

Flexible magnetoelectric (ME) generators gained immense interest due to the broad applications in wearable and Internet of Things (IoT)-based devices. The key to achieving high energy conversion performance of 0–3 type ME composite films is the prevention of filler aggregation in the polymer matrix and accessing the full potential of intrinsic properties of filler. To achieve high performance, a flexible ME composite film was fabricated by homogeneous distribution of magnetostrictive CoFe₂O₄-BaTiO₃ core-shell (CBCS) fillers into piezoelectric polyvinylidene fluoride (PVDF) polymer. The ME composite film generates an enhanced energy conversion efficiency by optimizing the shell thickness of CBCS and maximizing the electroactive β-phase at the BaTiO₃ shell-PVDF interfacial region. The observed ME coefficient of the film reached up to 710 mV/cm∙Oe. Multiphysics simulations based on the finite element analysis were adopted to investigate the role of BaTiO₃ shell thickness on the performance of ME film. This study paves the way to achieve higher filler loading content in the ME composite films to develop an efficient, flexible ME generator for eco-friendly permanent power sources.

柔性磁电（ME）发电机在可穿戴设备和物联网（IoT）设备中的广泛应用引起了人们的极大兴趣。0-3 型 ME 复合薄膜要实现高能量转换性能，关键在于防止填料在聚合物基体中聚集，并充分发挥填料固有特性的潜力。为了实现高性能，我们将磁致伸缩 CoFe2O4-BaTiO3 核壳（CBCS）填料均匀分布在压电聚偏氟乙烯（PVDF）聚合物中，制备出了一种柔性 ME 复合薄膜。通过优化 CBCS 的壳厚度和最大化 BaTiO3 壳-PVDF 界面区域的电活性 β 相，ME 复合薄膜产生了更高的能量转换效率。观察到的薄膜 ME 系数高达 710 mV/cm∙Oe。基于有限元分析的多物理场模拟研究了 BaTiO3 壳厚度对 ME 薄膜性能的影响。这项研究为在 ME 复合薄膜中实现更高的填料含量以开发高效、灵活的 ME 发电机铺平了道路，从而为环保型永久电源提供了可能。

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引用次数: 0