Pub Date : 2024-11-23DOI: 10.1016/j.jallcom.2024.177747
Vu Quoc Trung, Nguyen Dang Phu, Pham Van Hai, Chung-Li Dong, Ta Thi Thuy Nga, Wu-Ching Chou, Nguyen Thi Ngoc Hue, Pham Thi Hue, Luu Anh Tuyen, Nguyen Quang Hung, Luc Huy Hoang
High-quality two-dimensional Bi₂WO₆ nanolayers were synthesized via hydrothermal processes, with oxygen vacancies introduced through an ultrasound-assisted alkali etching treatment. Comprehensive characterization using Raman spectroscopy, X-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and positron annihilation spectroscopy (PAS) confirmed the presence and effects of these vacancies on the structural and electronic properties of the nanolayers. Raman spectroscopy revealed shifts in vibrational modes, particularly a blue shift in the WO₆ octahedral vibration modes, indicative of oxygen vacancy formation. XPS analysis showed a reduction in the binding energies of the Bi 4 f and W 4 f orbitals, confirming an altered electronic environment. TEM images demonstrated significant lattice distortions in the oxygen-vacancy-rich regions, particularly disordered WO₆ octahedra and disrupted Bi-O bond lengths. These distortions are consistent with the structural disorder observed in XAS measurements, which highlighted a reduction in the coordination number of W atoms and a corresponding contraction of W-O bond lengths. This charge redistribution between Bi and W atoms due to oxygen vacancies leads to localized structural perturbations, as further evidenced by PAS, which showed increased positron lifetimes associated with vacancy clusters, particularly around the Bi and W atoms. These vacancies create defective sites that trap photogenerated electrons, preventing their recombination with holes, thereby significantly enhancing photocatalytic performance. The enhanced photocatalytic activity was demonstrated by the nearly 98% degradation of Rhodamine B dye under visible-light irradiation, a substantial improvement over the 70% degradation achieved by the untreated sample. This work presents an innovative approach for generating stable oxygen vacancies in Bi₂WO₆ nanolayers and offers an in-depth understanding of the mechanisms that enhance photocatalytic performance, providing valuable insights for advancing photocatalysts designed for environmental remediation.
通过水热法合成了高质量的二维 Bi₂WO₆纳米层，并通过超声辅助碱蚀刻处理引入了氧空位。利用拉曼光谱、X 射线吸收光谱（XAS）、透射电子显微镜（TEM）、X 射线光电子能谱（XPS）和正电子湮灭光谱（PAS）进行的综合表征证实了这些空位的存在及其对纳米层结构和电子特性的影响。拉曼光谱显示了振动模式的变化，特别是 WO₆ 八面体振动模式的蓝移，表明了氧空位的形成。XPS 分析表明，Bi 4 f 和 W 4 f 轨道的结合能降低，证实电子环境发生了改变。TEM 图像显示氧空位富集区的晶格发生了明显的畸变，尤其是 WO₆ 八面体的无序和 Bi-O 键长度的中断。这些畸变与 XAS 测量中观察到的结构紊乱一致，XAS 测量突出显示了 W 原子配位数的减少和 W-O 键长度的相应收缩。氧空位导致的 Bi 原子和 W 原子间的电荷再分布导致了局部结构扰动，PAS 进一步证明了这一点，它显示了与空位簇相关的正电子寿命延长，尤其是在 Bi 原子和 W 原子周围。这些空位形成了缺陷位点，可捕获光生电子，阻止它们与空穴重组，从而显著提高光催化性能。在可见光照射下，罗丹明 B 染料的降解率接近 98%，与未经处理的样品 70% 的降解率相比有了大幅提高，这证明了光催化活性的增强。这项研究提出了一种在 Bi₂WO₆ 纳米层中产生稳定氧空位的创新方法，并深入揭示了提高光催化性能的机制，为推进环境修复光催化剂的设计提供了宝贵的见解。
{"title":"Enhancing Photocatalytic Performance in Bi₂WO₆ Nanolayers via Ultrasound-Assisted Oxygen Vacancy Engineering","authors":"Vu Quoc Trung, Nguyen Dang Phu, Pham Van Hai, Chung-Li Dong, Ta Thi Thuy Nga, Wu-Ching Chou, Nguyen Thi Ngoc Hue, Pham Thi Hue, Luu Anh Tuyen, Nguyen Quang Hung, Luc Huy Hoang","doi":"10.1016/j.jallcom.2024.177747","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177747","url":null,"abstract":"High-quality two-dimensional Bi₂WO₆ nanolayers were synthesized via hydrothermal processes, with oxygen vacancies introduced through an ultrasound-assisted alkali etching treatment. Comprehensive characterization using Raman spectroscopy, X-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and positron annihilation spectroscopy (PAS) confirmed the presence and effects of these vacancies on the structural and electronic properties of the nanolayers. Raman spectroscopy revealed shifts in vibrational modes, particularly a blue shift in the WO₆ octahedral vibration modes, indicative of oxygen vacancy formation. XPS analysis showed a reduction in the binding energies of the Bi 4<!-- --> <!-- -->f and W 4<!-- --> <!-- -->f orbitals, confirming an altered electronic environment. TEM images demonstrated significant lattice distortions in the oxygen-vacancy-rich regions, particularly disordered WO₆ octahedra and disrupted Bi-O bond lengths. These distortions are consistent with the structural disorder observed in XAS measurements, which highlighted a reduction in the coordination number of W atoms and a corresponding contraction of W-O bond lengths. This charge redistribution between Bi and W atoms due to oxygen vacancies leads to localized structural perturbations, as further evidenced by PAS, which showed increased positron lifetimes associated with vacancy clusters, particularly around the Bi and W atoms. These vacancies create defective sites that trap photogenerated electrons, preventing their recombination with holes, thereby significantly enhancing photocatalytic performance. The enhanced photocatalytic activity was demonstrated by the nearly 98% degradation of Rhodamine B dye under visible-light irradiation, a substantial improvement over the 70% degradation achieved by the untreated sample. This work presents an innovative approach for generating stable oxygen vacancies in Bi₂WO₆ nanolayers and offers an in-depth understanding of the mechanisms that enhance photocatalytic performance, providing valuable insights for advancing photocatalysts designed for environmental remediation.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"89 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142694235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ductile participation with small lattice misfit against matrix has been a long-sought-after character in toughening alloys, and recently multicomponent intermetallic nanoparticle L12 phase was explored by compositional modification in FeCoNi-based alloys and reported its benefits on strength and ductility through 780 °C for 4 h aging treatment. However, the L12 (A3B: Ni3Al) evolution in (FeCoNi)86-Al7Ti7 at a wide range of aging temperatures still lacks of comprehensive investigations. Herein, a series of aging temperatures (580 °C, 650 °C, 690 °C, 720 °C, 780 °C, and 820 °C) were carried out based on the synchrotron in-situ variable temperature XRD of the alloy. Results showed that both the composition and morphology of the L12 phase are dramatically dependent on the aging temperatures. Specifically, with aging temperature increased from 580 °C to 820 °C, A sites preferentially incorporated by more Co and Fe gradually turn into B sites partially substituted by Fe and Ti in the L12 phase, together with its morphology transforming from spherical to cuboidal. Meanwhile, the hierarchical microstructure induced by the precipitates of the tiny L12 phase at the aging temperature of 780 °C compensated the size departure of the primary L12 phase against the critical size to enhance the strength by enhancing its dislocation storage capacity. These hierarchical L12 phases strengthen the strong pair-coupling mechanism, ultimately illustrating its excellent strength-ductility balance aging at 780 °C against other aging temperatures.
与基体晶格错位小的韧性参与一直是增韧合金所追求的特性，最近通过成分改性在铁钴镍基合金中探索了多组分金属间纳米粒子 L12 相，并报道了其在 780 °C 4 小时时效处理中对强度和延展性的益处。然而，对于（FeCoNi）86-Al7Ti7 中的 L12（A3B：Ni3Al）在较宽的时效温度范围内的演化仍缺乏全面的研究。本文基于同步加速器原位变温 XRD 对合金进行了一系列老化温度（580 ℃、650 ℃、690 ℃、720 ℃、780 ℃ 和 820 ℃）的研究。结果表明，L12 相的成分和形态都与时效温度有很大关系。具体来说，随着时效温度从 580 ℃ 升高到 820 ℃，L12 相中由更多 Co 和铁优先结合的 A 位点逐渐转变为由铁和钛部分替代的 B 位点，其形态也从球形转变为立方体。同时，在 780 ℃ 的老化温度下，微小 L12 相的析出物所诱导的分层微观结构补偿了原生 L12 相的尺寸偏离临界尺寸的情况，从而通过提高其位错存储能力来增强强度。这些分层的 L12 相强化了强对偶机制，最终说明了在 780 °C 老化温度下与其他老化温度相比，该材料具有出色的强度-电导率平衡能力。
{"title":"Evolution of Ductile L12 Phase in (FeCoNi)86-Al7Ti7 High-Entropy Alloy Aging at Various Temperatures and Its Strengthening Mechanism","authors":"Chenlei Shen, Feng Jiang, Chenyu Xu, Mingqin Xu, Lisha Liu, Zhenni Zhou, Fangyuan Zhu, Jiaojiao Yi","doi":"10.1016/j.jallcom.2024.177729","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177729","url":null,"abstract":"Ductile participation with small lattice misfit against matrix has been a long-sought-after character in toughening alloys, and recently multicomponent intermetallic nanoparticle L1<sub>2</sub> phase was explored by compositional modification in FeCoNi-based alloys and reported its benefits on strength and ductility through 780 °C for 4<!-- --> <!-- -->h aging treatment. However, the L1<sub>2</sub> (A<sub>3</sub>B: Ni<sub>3</sub>Al) evolution in (FeCoNi)<sub>86</sub>-Al<sub>7</sub>Ti<sub>7</sub> at a wide range of aging temperatures still lacks of comprehensive investigations. Herein, a series of aging temperatures (580 °C, 650 °C, 690 °C, 720 °C, 780 °C, and 820 °C) were carried out based on the synchrotron in-situ variable temperature XRD of the alloy. Results showed that both the composition and morphology of the L1<sub>2</sub> phase are dramatically dependent on the aging temperatures. Specifically, with aging temperature increased from 580 °C to 820 °C, A sites preferentially incorporated by more Co and Fe gradually turn into B sites partially substituted by Fe and Ti in the L1<sub>2</sub> phase, together with its morphology transforming from spherical to cuboidal. Meanwhile, the hierarchical microstructure induced by the precipitates of the tiny L1<sub>2</sub> phase at the aging temperature of 780 °C compensated the size departure of the primary L1<sub>2</sub> phase against the critical size to enhance the strength by enhancing its dislocation storage capacity. These hierarchical L1<sub>2</sub> phases strengthen the strong pair-coupling mechanism, ultimately illustrating its excellent strength-ductility balance aging at 780 °C against other aging temperatures.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"13 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142690948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.jallcom.2024.177727
Shuo Ma, Panmei Liu, Liming Yu, Yuan Huang, Zumin Wang
The structural order significantly influences the oxidation resistance of alloys, but its effect on oxidation behaviors in humid environments remains underexplored. Herein, a comprehensive investigation of the effect of structural order on the wet oxidation of alloys was conducted using amorphous and crystalline Zr-Cu-Al alloys as model systems. The amorphous Zr-Cu-Al alloy exhibits stronger resistance to wet oxidation than its crystalline counterpart, which can be ascribed to the higher activation barriers associated with dense and disordered atomic structures of amorphous (Zr, Al)-oxide and substrate. An amorphous Cu-rich structure is observed in the amorphous alloy, whereas internal oxidation occurs in the crystalline alloy with a resulting multilayered Cu-rich structure (i.e. intermetallic compounds). This study highlights the critical role of structural order in oxidation resistance, providing new insights into the design strategies of alloys served in humid environments.
{"title":"Comparative study of wet oxidation in amorphous and crystalline Zr-Cu-Al: The effect of structural order","authors":"Shuo Ma, Panmei Liu, Liming Yu, Yuan Huang, Zumin Wang","doi":"10.1016/j.jallcom.2024.177727","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177727","url":null,"abstract":"The structural order significantly influences the oxidation resistance of alloys, but its effect on oxidation behaviors in humid environments remains underexplored. Herein, a comprehensive investigation of the effect of structural order on the wet oxidation of alloys was conducted using amorphous and crystalline Zr-Cu-Al alloys as model systems. The amorphous Zr-Cu-Al alloy exhibits stronger resistance to wet oxidation than its crystalline counterpart, which can be ascribed to the higher activation barriers associated with dense and disordered atomic structures of amorphous (Zr, Al)-oxide and substrate. An amorphous Cu-rich structure is observed in the amorphous alloy, whereas internal oxidation occurs in the crystalline alloy with a resulting multilayered Cu-rich structure (i.e. intermetallic compounds). This study highlights the critical role of structural order in oxidation resistance, providing new insights into the design strategies of alloys served in humid environments.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"59 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142690952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.jallcom.2024.177733
Panzhen Li, Zhe Huang, Jin Yang, Chenhe Zhang, Siwei Tang, Yunzhu Ma, Wensheng Liu
As an important interconnecting material for solar cells, photovoltaic silver paste is in high demand. The silver powder, used as the conductive phase, greatly influences the conductivity of the paste. In this study, microfluidic technology was employed to achieve rapid and uniform mixing at the molecular level and the influence of microfluidic process conditions and reaction rates on silver powder morphology was investigated. Particularly, microfluidic technology can prevent the heterogeneous nucleation on wall of container. Using a 1.5 mol/L ascorbic acid concentration, spherical silver powder measuring 0.70–0.80 μm was produced through the convection reaction of two microflows at a 10 mL/min flow rate. This silver powder exhibited better shape regularization compared to that produced by macromixing. When mixed with micron flake silver powder in a 1:1 mass ratio and sintered at 150℃ for 45 min, the microfluidically prepared silver powder achieved a resistivity of 2.72 × 10−5 Ω.cm. This work introduces a new approach for preparing submicron silver powder, which has important applications in the solar cell silver paste field.
{"title":"Container-Free Microfluidic Chemical Reduction for Synthesizing Ultrafine Silver Powder and Fabricating Silver Paste","authors":"Panzhen Li, Zhe Huang, Jin Yang, Chenhe Zhang, Siwei Tang, Yunzhu Ma, Wensheng Liu","doi":"10.1016/j.jallcom.2024.177733","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177733","url":null,"abstract":"As an important interconnecting material for solar cells, photovoltaic silver paste is in high demand. The silver powder, used as the conductive phase, greatly influences the conductivity of the paste. In this study, microfluidic technology was employed to achieve rapid and uniform mixing at the molecular level and the influence of microfluidic process conditions and reaction rates on silver powder morphology was investigated. Particularly, microfluidic technology can prevent the heterogeneous nucleation on wall of container. Using a 1.5<!-- --> <!-- -->mol/L ascorbic acid concentration, spherical silver powder measuring 0.70–0.80 μm was produced through the convection reaction of two microflows at a 10<!-- --> <!-- -->mL/min flow rate. This silver powder exhibited better shape regularization compared to that produced by macromixing. When mixed with micron flake silver powder in a 1:1 mass ratio and sintered at 150℃ for 45<!-- --> <!-- -->min, the microfluidically prepared silver powder achieved a resistivity of 2.72 × 10<sup>−5</sup> Ω.cm. This work introduces a new approach for preparing submicron silver powder, which has important applications in the solar cell silver paste field.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"24 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142690951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1016/j.jallcom.2024.177719
Chao Ma, Teng Su, Zhuohang Li, Bei Ren, Ziqian Meng, Bo Li, Ruixin Hao, Yang Miao, Feng Gao
Development of microwave dielectric ceramics with a high dielectric constant, high quality factor, and low temperature coefficient of resonant frequency is of great importance for achieving miniaturization, low loss, and high stability in microwave devices. Research on low dielectric constant microwave dielectric ceramics has made certain progress, but the development of new systems of high dielectric constant microwave dielectric ceramics with excellent overall performance is still in the exploratory stage. Herein, approaches of high-entropy strategy and small radius ions doping were combined to achieve high microwave dielectric properties. It is demonstrated that a high-entropy ceramic with a perovskite structure doped with Al3+ ion, denoted as (Ba0.25Ca0.25Sr0.25La0.25)Ti1-xAlxO3 (abbreviated as HESOs, 0<x≤0.25), was successfully synthesized. At x=0.1 and 1500 oC, HESO exhibited optimized comprehensive dielectric performance, characterized by εr = 89.25, Q×f = 3304 GHz, and τf = +361 ppm/oC. Besides, as the aluminum ion content increases, there is a reduction in grain size accompanied by an elevation in oxygen vacancy content, resulting in increase of Q×f, with a peak value reaching 4136 GHz. This study presents a valuable exploration aimed at designing high-entropy perovskite ceramics with excellent dielectric properties.
{"title":"Preparation of (Ba0.25Ca0.25Sr0.25La0.25)Ti1-xAlxO3 High-Entropy Perovskite Ceramics for enhanced Microwave Dielectric Performance","authors":"Chao Ma, Teng Su, Zhuohang Li, Bei Ren, Ziqian Meng, Bo Li, Ruixin Hao, Yang Miao, Feng Gao","doi":"10.1016/j.jallcom.2024.177719","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177719","url":null,"abstract":"Development of microwave dielectric ceramics with a high dielectric constant, high quality factor, and low temperature coefficient of resonant frequency is of great importance for achieving miniaturization, low loss, and high stability in microwave devices. Research on low dielectric constant microwave dielectric ceramics has made certain progress, but the development of new systems of high dielectric constant microwave dielectric ceramics with excellent overall performance is still in the exploratory stage. Herein, approaches of high-entropy strategy and small radius ions doping were combined to achieve high microwave dielectric properties. It is demonstrated that a high-entropy ceramic with a perovskite structure doped with Al<sup>3+</sup> ion, denoted as (Ba<sub>0.25</sub>Ca<sub>0.25</sub>Sr<sub>0.25</sub>La<sub>0.25</sub>)Ti<sub>1-x</sub>Al<sub>x</sub>O<sub>3</sub> (abbreviated as HESOs, 0<<em>x</em>≤0.25), was successfully synthesized. At <em>x</em>=0.1 and 1500<!-- --> <sup>o</sup>C, HESO exhibited optimized comprehensive dielectric performance, characterized by <em>ε</em><sub><em>r</em></sub> = 89.25, <em>Q</em>×<em>f</em> = 3304<!-- --> <!-- -->GHz, and <em>τ</em><sub><em>f</em></sub> = +361 ppm<sub>/</sub><sup>o</sup>C. Besides, as the aluminum ion content increases, there is a reduction in grain size accompanied by an elevation in oxygen vacancy content, resulting in increase of <em>Q</em>×<em>f</em>, with a peak value reaching 4136<!-- --> <!-- -->GHz. This study presents a valuable exploration aimed at designing high-entropy perovskite ceramics with excellent dielectric properties.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"310 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1016/j.jallcom.2024.177709
Hongyuan Song, Yijia Pang, Linjie Dong, Kun Dong, Haorong Wu, Liangwei Chen, Bin Liu, Zhenhua Ge, Lan Yu
Transition metal oxides are considered ideal electrocatalyst materials due to their low cost and high intrinsic activity. Among them, SrCoO3-δ has received increasing attention due to its multi-phase structure and tunable electronic properties, though its OER reaction kinetics and catalysis stability are unsatisfactory. Herein, based on a simple one-step solid-state reaction method, we use a small amount of rare earth Y ions (10%) to transform H-SCO2.52 from a hexagonal structure to a stable cubic perovskite Sr0.9Y0.1CoO3−δ. While broadening the atomic ratio of Co and Fe in the B-site under the cubic perovskite Sr0.9Y0.1Co1-xFexO3−δ (x = 0~1), the relationship between the B-site electronic state, oxygen vacancies, and OER performance has been explored. Sr0.9Y0.1Co0.2Fe0.8O3−δ with a high concentration of oxygen vacancies, exhibits the lowest overpotential of 277 mV and maintains stability at 10 mA cm-2 for 88 hours. The valence states of Fe and Co atoms in SYC0.2F0.8 O are optimized (Fe2+~50.81%, Co2+~19.39%), and the oxygen evolution activity is enhanced by electrochemical reconfiguration to form high-valence Fe and Co ions. Selective leaching of Sr ions via electrochemical surface reconstruction activates FeOOH and CoOOH amorphous layer active sites on the catalyst surface, significantly enhancing reaction kinetics.
过渡金属氧化物因其低成本和高内在活性而被认为是理想的电催化剂材料。其中，SrCoO3-δ因其多相结构和可调的电子特性受到越来越多的关注，但其OER反应动力学和催化稳定性并不理想。在此，我们基于简单的一步固态反应方法，利用少量稀土 Y 离子（10%）将 H-SCO2.52 从六方结构转变为稳定的立方包晶 Sr0.9Y0.1CoO3-δ。在拓宽立方包晶 Sr0.9Y0.1Co1-xFexO3-δ（x = 0~1）B 位中 Co 和 Fe 原子比例的同时，还探讨了 B 位电子状态、氧空位和 OER 性能之间的关系。氧空位浓度较高的 Sr0.9Y0.1Co0.2Fe0.8O3-δ 显示出 277 mV 的最低过电位，并能在 10 mA cm-2 下保持稳定 88 小时。SYC0.2F0.8 O 中铁原子和钴原子的价态得到优化（Fe2+~50.81%，Co2+~19.39%），通过电化学重构形成高价态的铁离子和钴离子，提高了氧进化活性。通过电化学表面重构选择性浸出 Sr 离子激活了催化剂表面的 FeOOH 和 CoOOH 非晶层活性位点，显著提高了反应动力学。
{"title":"High stability cubic perovskite Sr0.9Y0.1Co1-xFexO3-δ oxygen evolution by phase control and electrochemical reconstruction","authors":"Hongyuan Song, Yijia Pang, Linjie Dong, Kun Dong, Haorong Wu, Liangwei Chen, Bin Liu, Zhenhua Ge, Lan Yu","doi":"10.1016/j.jallcom.2024.177709","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177709","url":null,"abstract":"Transition metal oxides are considered ideal electrocatalyst materials due to their low cost and high intrinsic activity. Among them, SrCoO<sub>3-<em>δ</em></sub> has received increasing attention due to its multi-phase structure and tunable electronic properties, though its OER reaction kinetics and catalysis stability are unsatisfactory. Herein, based on a simple one-step solid-state reaction method, we use a small amount of rare earth Y ions (10%) to transform H-SCO<sub>2.52</sub> from a hexagonal structure to a stable cubic perovskite Sr<sub>0.9</sub>Y<sub>0.1</sub>CoO<sub>3−<em>δ</em></sub>. While broadening the atomic ratio of Co and Fe in the B-site under the cubic perovskite Sr<sub>0.9</sub>Y<sub>0.1</sub>Co<sub>1-<em>x</em></sub>Fe<sub><em>x</em></sub>O<sub>3−<em>δ</em></sub> (<em>x</em> = 0~1), the relationship between the B-site electronic state, oxygen vacancies, and OER performance has been explored. Sr<sub>0.9</sub>Y<sub>0.1</sub>Co<sub>0.2</sub>Fe<sub>0.8</sub>O<sub>3−<em>δ</em></sub> with a high concentration of oxygen vacancies, exhibits the lowest overpotential of 277<!-- --> <!-- -->mV and maintains stability at 10<!-- --> <!-- -->mA<!-- --> <!-- -->cm<sup>-2</sup> for 88<!-- --> <!-- -->hours. The valence states of Fe and Co atoms in SYC0.2F0.8<!-- --> <!-- -->O are optimized (Fe<sup>2+</sup>~50.81%, Co<sup>2+</sup>~19.39%), and the oxygen evolution activity is enhanced by electrochemical reconfiguration to form high-valence Fe and Co ions. Selective leaching of Sr ions via electrochemical surface reconstruction activates FeOOH and CoOOH amorphous layer active sites on the catalyst surface, significantly enhancing reaction kinetics.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"18 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The TiO2 doped CaNb2O6 ceramics were successfully prepared by solid state reaction in this work. The XRD and Rietveld refinement results of the CaNb2-xTixO6 (0≤x≤0.025) showed that Ti4+ entered the Nb5+ lattice site and replaced a part of Nb5+, forming a substitutional solid solution. The XPS results of the CaNb2-xTixO6 ceramics explained that Ti4+ entered the Nb5+ lattice position and caused the formation of oxygen vacancies. Dipoles caused by oxygen vacancies limited the long-range transition of electrons, resulting in electron pinning effect. The SEM results displayed that with the addition of Ti4+, the structure of CaNb2-xTixO6 ceramics densified rapidly. The dielectric constant (εr), resonant frequency (τf) and quality factor (Q×f) values were related to density, bond valence, anharmonic motion between atoms and crystallinity, respectively, which provided a theoretical basis for further regulating microwave dielectric properties. When the doping amount of Ti4+ increased from 0.005 to 0.02, the τf value increased from -62ppm/°C to -22ppm/°C. The CaNb2-xTixO6 ceramics with x=0.02 sintered at 1425 °C for 4 h had excellent microwave dielectric properties: εr = 15.76, Q×f =30397 GHz, τf =-22 ppm/°C.
{"title":"Effect of TiO2 doping on microstructure and microwave dielectric properties of CaNb2O6 ceramics","authors":"Zehui Lin, Yuanming Lai, Menghong Li, Jiaqi He, Mingwei Li, Ju Zhou, Shiqi Li, Wenhan Qi, Jiao Han, Yiming Zeng","doi":"10.1016/j.jallcom.2024.177717","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177717","url":null,"abstract":"The TiO<sub>2</sub> doped CaNb<sub>2</sub>O<sub>6</sub> ceramics were successfully prepared by solid state reaction in this work. The XRD and Rietveld refinement results of the CaNb<sub>2-x</sub>Ti<sub>x</sub>O<sub>6</sub> (0≤x≤0.025) showed that Ti<sup>4+</sup> entered the Nb<sup>5+</sup> lattice site and replaced a part of Nb<sup>5+</sup>, forming a substitutional solid solution. The XPS results of the CaNb<sub>2-x</sub>Ti<sub>x</sub>O<sub>6</sub> ceramics explained that Ti<sup>4+</sup> entered the Nb<sup>5+</sup> lattice position and caused the formation of oxygen vacancies. Dipoles caused by oxygen vacancies limited the long-range transition of electrons, resulting in electron pinning effect. The SEM results displayed that with the addition of Ti<sup>4+</sup>, the structure of CaNb<sub>2-x</sub>Ti<sub>x</sub>O<sub>6</sub> ceramics densified rapidly. The dielectric constant (ε<sub>r</sub>), resonant frequency (τ<sub>f</sub>) and quality factor (Q×f) values were related to density, bond valence, anharmonic motion between atoms and crystallinity, respectively, which provided a theoretical basis for further regulating microwave dielectric properties. When the doping amount of Ti<sup>4+</sup> increased from 0.005 to 0.02, the τ<sub>f</sub> value increased from -62ppm/°C to -22ppm/°C. The CaNb<sub>2-x</sub>Ti<sub>x</sub>O<sub>6</sub> ceramics with x=0.02 sintered at 1425 °C for 4<!-- --> <!-- -->h had excellent microwave dielectric properties: ε<sub>r</sub> = 15.76, Q×f =30397<!-- --> <!-- -->GHz, τ<sub>f</sub> =-22 ppm/°C.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"4 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, Cu-Mn-P alloys with Mn/P atomic ratios ranging from 1 to 3 were designed based on computational phase diagrams. The microstructures of these alloys were systematically investigated using a combination of TEM, EPMA, EBSD, and XRD. The results indicate that the alloy with a Mn/P atomic ratio of 2 exhibits optimal comprehensive properties. A simple thermomechanical treatment involving solution treatment followed by 70% cold rolling and aging at 400°C for 6 hours resulted in a hardness of 186.8 HV, a tensile strength of 577 MPa, a yield strength of 548 MPa, and an electrical conductivity of 63.5% IACS. Alloys with Mn/P ratios below 2 showed a reduced density of precipitates, leading to diminished precipitation hardening, while higher ratios resulted in increased manganese content in the solid solution, causing lattice distortions and reduced conductivity. TEM analysis confirmed that the precipitated phase was rod-shaped hexagonal Mn2P, which grew along the (100) plane of the matrix and maintained a coherent interface with the matrix. This research provides insights for the future development of high-performance quaternary Cu-Mn-X-P alloys.
{"title":"Effect of Mn/P Atomic Ratio on the Microstructure and Properties of Cu-Mn-P Alloy","authors":"Chengzhi Zhang, Xue Xiao, Rui Zhou, Weilin Gao, Qingkui Li, Jilin He","doi":"10.1016/j.jallcom.2024.177705","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177705","url":null,"abstract":"In this study, Cu-Mn-P alloys with Mn/P atomic ratios ranging from 1 to 3 were designed based on computational phase diagrams. The microstructures of these alloys were systematically investigated using a combination of TEM, EPMA, EBSD, and XRD. The results indicate that the alloy with a Mn/P atomic ratio of 2 exhibits optimal comprehensive properties. A simple thermomechanical treatment involving solution treatment followed by 70% cold rolling and aging at 400°C for 6<!-- --> <!-- -->hours resulted in a hardness of 186.8 HV, a tensile strength of 577<!-- --> <!-- -->MPa, a yield strength of 548<!-- --> <!-- -->MPa, and an electrical conductivity of 63.5% IACS. Alloys with Mn/P ratios below 2 showed a reduced density of precipitates, leading to diminished precipitation hardening, while higher ratios resulted in increased manganese content in the solid solution, causing lattice distortions and reduced conductivity. TEM analysis confirmed that the precipitated phase was rod-shaped hexagonal Mn<sub>2</sub>P, which grew along the (100) plane of the matrix and maintained a coherent interface with the matrix. This research provides insights for the future development of high-performance quaternary Cu-Mn-X-P alloys.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"81 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1016/j.jallcom.2024.177721
Yunfei Ma, Pan Gong, Xuxiao Yang, Huie Hu, Junhan Chi, Xiao Xu, Xin Wang, Mao Zhang, Xinyun Wang
This study examines tungsten-particle (Wp) reinforced Zr-based bulk metallic glass composites (Wp/BMGCs) with 30% and 50% volume fractions, fabricated via Two-Step Spark Plasma Sintering (TSS) and Normal Spark Plasma Sintering (NS). The influence of the reinforcing phase particle size on the microstructure and mechanical properties of the material was systematically analyzed. The results reveal that reducing the Wp particle size from 200 μm to 30 μm profoundly influences the composite's interfacial and distribution effects, consequently altering its microstructure and mechanical properties. At higher Wp volume fractions, smaller particles tend to agglomerate, but increasing Wp particle size improves the reinforcement phase distribution. The densification of Wp/BMGCs is mainly influenced by interfacial effects, with smaller Wp particle sizes enhancing densification. TSS enhances interfacial bonding, further improving densification. Mechanical properties are primarily governed by interfacial effects in 30% Wp/BMGCs and 50% Wp/BMGCs prepared by NS, with smaller Wp particle sizes leading to enhanced properties. However, for 50% Wp/BMGCs prepared by TSS, distribution effects dominate at smaller sizes, with TSS process exacerbates agglomeration, deteriorating mechanical performance. Micromechanical simulations show that Wp restricts shear band expansion and promotes cross proliferation, enhancing the material's overall mechanical performance.
{"title":"Microstructure and Mechanical Properties of Zr-Based Metallic Glass Composites with Size-Variable Tungsten Reinforcements","authors":"Yunfei Ma, Pan Gong, Xuxiao Yang, Huie Hu, Junhan Chi, Xiao Xu, Xin Wang, Mao Zhang, Xinyun Wang","doi":"10.1016/j.jallcom.2024.177721","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177721","url":null,"abstract":"This study examines tungsten-particle (Wp) reinforced Zr-based bulk metallic glass composites (Wp/BMGCs) with 30% and 50% volume fractions, fabricated via Two-Step Spark Plasma Sintering (TSS) and Normal Spark Plasma Sintering (NS). The influence of the reinforcing phase particle size on the microstructure and mechanical properties of the material was systematically analyzed. The results reveal that reducing the Wp particle size from 200 μm to 30 μm profoundly influences the composite's interfacial and distribution effects, consequently altering its microstructure and mechanical properties. At higher Wp volume fractions, smaller particles tend to agglomerate, but increasing Wp particle size improves the reinforcement phase distribution. The densification of Wp/BMGCs is mainly influenced by interfacial effects, with smaller Wp particle sizes enhancing densification. TSS enhances interfacial bonding, further improving densification. Mechanical properties are primarily governed by interfacial effects in 30% Wp/BMGCs and 50% Wp/BMGCs prepared by NS, with smaller Wp particle sizes leading to enhanced properties. However, for 50% Wp/BMGCs prepared by TSS, distribution effects dominate at smaller sizes, with TSS process exacerbates agglomeration, deteriorating mechanical performance. Micromechanical simulations show that Wp restricts shear band expansion and promotes cross proliferation, enhancing the material's overall mechanical performance.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"78 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents a flexible hybrid nanogenerator that utilizes lead-free KNNS-BF-xBNZ materials integrated with polydimethylsiloxane (PDMS) to enhance energy harvesting performance. The findings demonstrate that by combining piezoelectric and triboelectric effects, the energy conversion efficiency of the nanogenerator is significantly improved, resulting in high output voltage and current, suitable for real-world applications. Specifically, the optimal composition of KNNS-BF-xBNZ ceramics, with x = 0.03 mol.%, yields superior piezoelectric, ferroelectric, and dielectric properties, with remnant polarization (Pr), spontaneous polarization (Ps), and piezoelectric coefficient (d33) values reaching 18.8 μmC/cm², 30.3 μmC/cm², and 358 pC/N, respectively. In the hybrid device, incorporating 15 wt.% of KNNS-BF-3BNZ into PDMS resulted in the highest open-circuit voltage (VOC) of 107 V and short-circuit current (ISC) of 4.68 μA. The developed hybrid nanogenerator effectively charges capacitors for energy storage, powers LEDs, and drives small electronic devices, such as watches, showcasing its potential for practical energy harvesting applications. The findings suggest that the integration of KNNS-BF-3BNZ with PDMS provides an efficient and scalable pathway for fabricating high-performance nanogenerators, paving the way for advancements in self-powered devices and sustainable energy solutions.
{"title":"Next-Generation Hybrid Nanogenerators Using Giant Piezoelectric Lead-Free KNNS Composites for Sustainable Self-Powered Electronics","authors":"Rattiphorn Sumang, Thitirat Charoonsuk, Theerachai Bongkarn, Te-Wei Chiu, Naratip Vittayakorn, Phakakorn Panpho","doi":"10.1016/j.jallcom.2024.177681","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177681","url":null,"abstract":"This study presents a flexible hybrid nanogenerator that utilizes lead-free KNNS-BF-<em>x</em>BNZ materials integrated with polydimethylsiloxane (PDMS) to enhance energy harvesting performance. The findings demonstrate that by combining piezoelectric and triboelectric effects, the energy conversion efficiency of the nanogenerator is significantly improved, resulting in high output voltage and current, suitable for real-world applications. Specifically, the optimal composition of KNNS-BF-xBNZ ceramics, with <em>x</em> = 0.03<!-- --> <!-- -->mol.%, yields superior piezoelectric, ferroelectric, and dielectric properties, with remnant polarization (<em>P</em><sub>r</sub>), spontaneous polarization (<em>P</em><sub>s</sub>), and piezoelectric coefficient (<em>d</em><sub>33</sub>) values reaching 18.8 μmC/cm², 30.3 μmC/cm², and 358 pC/N, respectively. In the hybrid device, incorporating 15<!-- --> <!-- -->wt.% of KNNS-BF-3BNZ into PDMS resulted in the highest open-circuit voltage (<em>V</em><sub>OC</sub>) of 107<!-- --> <!-- -->V and short-circuit current (<em>I</em><sub>SC</sub>) of 4.68 μA. The developed hybrid nanogenerator effectively charges capacitors for energy storage, powers LEDs, and drives small electronic devices, such as watches, showcasing its potential for practical energy harvesting applications. The findings suggest that the integration of KNNS-BF-3BNZ with PDMS provides an efficient and scalable pathway for fabricating high-performance nanogenerators, paving the way for advancements in self-powered devices and sustainable energy solutions.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"19 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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