The magneto‐optical properties of rare‐earth‐rich borate glasses prepared using a levitation technique were thoroughly investigated. Among the series of rare‐earth borate glasses, Tb2O3–B2O3 and Dy2O3–B2O3 glasses displayed remarkably large Faraday effects in the visible region. The Verdet constant of 58Tb2O3–42B2O3 reached −229 rad/T·m at 633 nm, surpassing the value of commercially available single‐crystalline Tb3Ga5O12. Compositions with a higher rare‐earth oxide content (60 mol%) than that of binary glasses facilitated the successful synthesis of Tb2O3–Dy2O3–B2O3 ternary glasses. The Verdet constant linearly increased with increasing Tb2O3 content for the glasses with 40 mol% B2O3. Results indicate that rare‐earth‐rich borate glasses are promising candidates for magneto‐optical applications in the visible region, and that the types and amounts of rare‐earth ion mainly affect these properties.
{"title":"Magneto‐optical effect of rare‐earth‐rich borate glasses prepared using a levitation technique","authors":"Shunta Sasaki, Katsuhisa Tanaka, Atsunobu Masuno","doi":"10.1111/jace.20065","DOIUrl":"https://doi.org/10.1111/jace.20065","url":null,"abstract":"The magneto‐optical properties of rare‐earth‐rich borate glasses prepared using a levitation technique were thoroughly investigated. Among the series of rare‐earth borate glasses, Tb<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>–B<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> and Dy<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>–B<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> glasses displayed remarkably large Faraday effects in the visible region. The Verdet constant of 58Tb<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>–42B<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> reached −229 rad/T·m at 633 nm, surpassing the value of commercially available single‐crystalline Tb<jats:sub>3</jats:sub>Ga<jats:sub>5</jats:sub>O<jats:sub>12</jats:sub>. Compositions with a higher rare‐earth oxide content (60 mol%) than that of binary glasses facilitated the successful synthesis of Tb<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>–Dy<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>–B<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> ternary glasses. The Verdet constant linearly increased with increasing Tb<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> content for the glasses with 40 mol% B<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>. Results indicate that rare‐earth‐rich borate glasses are promising candidates for magneto‐optical applications in the visible region, and that the types and amounts of rare‐earth ion mainly affect these properties.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 utilized an innovative unalloyed CoCrFeNiTiMo hybrid powder as a joining filler to fabricate high‐strength SiC/HEA/SiC joints via in‐situ reaction. The investigation systematically examines the effects of joining parameters on microstructural evolution and mechanical properties. The filler exhibits high reactivity with SiC, addressing carbon enrichment and low‐strength issues. The resulting joining layer comprises HEA‐rich Si, Mo1.5Cr1.5Si, MoTiC2, and TiC phases. Increasing the temperature facilitates carbon diffusion, transforming TiC into MoTiC2 and forming a MoTiC2‐wrapped TiC structure. At 1400°C for 60 min, the joints attain peak flexural and shear strengths of 312 ± 16 and 137 ± 10 MPa, respectively. Additionally, the joints demonstrate excellent oxidation resistance, with a residual strength of 270 ± 7 MPa after 20 h at 900°C, and favorable high‐temperature mechanical strength, retaining 155 ± 14 MPa at 1000°C. A detailed analysis of the joint formation mechanism is conducted based on experimental results and first‐principles calculations.
{"title":"In‐situ fabrication of high‐strength SiC joints utilizing a novel CoCrFeNiTiMo high‐entropy alloy filler","authors":"Changcong Huang, Jian Chen, Huihui Zhang, Shengjun Liao, Chenxi Gao, Lan Peng, Xuejian Liu, Zhengren Huang","doi":"10.1111/jace.20044","DOIUrl":"https://doi.org/10.1111/jace.20044","url":null,"abstract":"This study utilized an innovative unalloyed CoCrFeNiTiMo hybrid powder as a joining filler to fabricate high‐strength SiC/HEA/SiC joints via in‐situ reaction. The investigation systematically examines the effects of joining parameters on microstructural evolution and mechanical properties. The filler exhibits high reactivity with SiC, addressing carbon enrichment and low‐strength issues. The resulting joining layer comprises HEA‐rich Si, Mo<jats:sub>1.5</jats:sub>Cr<jats:sub>1.5</jats:sub>Si, MoTiC<jats:sub>2</jats:sub>, and TiC phases. Increasing the temperature facilitates carbon diffusion, transforming TiC into MoTiC<jats:sub>2</jats:sub> and forming a MoTiC<jats:sub>2</jats:sub>‐wrapped TiC structure. At 1400°C for 60 min, the joints attain peak flexural and shear strengths of 312 ± 16 and 137 ± 10 MPa, respectively. Additionally, the joints demonstrate excellent oxidation resistance, with a residual strength of 270 ± 7 MPa after 20 h at 900°C, and favorable high‐temperature mechanical strength, retaining 155 ± 14 MPa at 1000°C. A detailed analysis of the joint formation mechanism is conducted based on experimental results and first‐principles calculations.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 investigates the dynamics of ice crystal growth and stress distribution in nanoconfined spaces using molecular dynamics simulations. First, the interaction between the pore wall and coarse-grained water is modified, leading to the development of pore models with varying wettability. Subsequently, the process of ice crystal growth within pores of 10 nm diameter is examined under different temperatures and hydrophobicity conditions. Results unveil that ice crystal growth induces substantial energy and enthalpy alterations within the system. Hydrophobic nanopores demonstrate a protective function by limiting ice crystal growth and water transport, thereby mitigating freezing damage. However, hydrophobic nanopores exhibit increased stress levels when saturated with water. The study employs the Zener pinning theory and mass transfer rates to qualitatively scrutinize the thermodynamic and kinetic interplay between the ice crystal interface and the degree of supercooling. These findings offer insights into the mechanisms of ice formation and stress evolution in nanoconfined environments.
{"title":"Mechanisms of ice crystal growth in nanoconfined spaces of cementitious composites at low temperatures: Insights from molecular dynamics simulations","authors":"Zhiyu Wang, Yuxin Zhou, Yuan Feng, Junjie Zhang, Rui Yu, Zechuan Yu","doi":"10.1111/jace.20047","DOIUrl":"https://doi.org/10.1111/jace.20047","url":null,"abstract":"This study investigates the dynamics of ice crystal growth and stress distribution in nanoconfined spaces using molecular dynamics simulations. First, the interaction between the pore wall and coarse-grained water is modified, leading to the development of pore models with varying wettability. Subsequently, the process of ice crystal growth within pores of 10 nm diameter is examined under different temperatures and hydrophobicity conditions. Results unveil that ice crystal growth induces substantial energy and enthalpy alterations within the system. Hydrophobic nanopores demonstrate a protective function by limiting ice crystal growth and water transport, thereby mitigating freezing damage. However, hydrophobic nanopores exhibit increased stress levels when saturated with water. The study employs the Zener pinning theory and mass transfer rates to qualitatively scrutinize the thermodynamic and kinetic interplay between the ice crystal interface and the degree of supercooling. These findings offer insights into the mechanisms of ice formation and stress evolution in nanoconfined environments.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142198418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Linhai Li, Yongxin Zhou, Xuefeng Chen, Genshui Wang
(Pb,La)(Zr,Ti)O3 antiferroelectric (AFE) ceramics have attracted considerable interest due to their high‐energy storage density and numerous field‐induced phase transitions. However, the positional equilibrium of the A‐site and B‐site is typically maintained without considering that heterovalent doping of La3+ can induce defects within the material, leading to high‐temperature leakage conduction. In this work, we introduced the acceptor ion Na+ at the A‐site simultaneously and designed Pb0.9175–0.5xLa0.055NaxZr0.975Ti0.025O3 (x = 0.01, 0.03, 0.055, 0.07, 0.10) AFE ceramics. The dielectric properties of these ceramics exhibited a consistent pattern of improvement followed by deterioration as the content of Na+ increased. Notably, when x = 0.055 (Na5.5), the AFE ceramic demonstrated superior high‐temperature frequency stability with negligible leakage conduction. Impedance spectroscopy analysis suggested that Na5.5 displays the greatest resistance and highest Edc. Concurrently, the thermally stimulated depolarization current indicates that Na5.5 possesses the lowest defect concentration and the largest Ea. This can be attributed to the internal generation of defect dipole clusters (), which effectively restrict the movement of charged defects. These findings suggest that Na5.5 holds significant potential for application and offer insights into the understanding of internal defects in lead‐based AFE materials.
(Pb,La)(Zr,Ti)O3反铁电（AFE）陶瓷因其高能量存储密度和众多场致相变而备受关注。然而，在维持 A 位和 B 位的位置平衡时，通常没有考虑到 La3+ 的异价掺杂会诱发材料内部的缺陷，从而导致高温漏导。在这项工作中，我们在 A 位同时引入了受体离子 Na+，并设计出了 Pb0.9175-0.5xLa0.055NaxZr0.975Ti0.025O3 (x = 0.01, 0.03, 0.055, 0.07, 0.10) AFE 陶瓷。随着 Na+ 含量的增加，这些陶瓷的介电性能呈现出先改善后恶化的一致模式。值得注意的是，当 x = 0.055（Na5.5）时，AFE 陶瓷表现出卓越的高温频率稳定性，漏导几乎可以忽略不计。阻抗光谱分析表明，Na5.5 具有最大的电阻和最高的 Edc。同时，热刺激去极化电流表明，Na5.5 具有最低的缺陷浓度和最大的 Ea。这可归因于内部产生的缺陷偶极簇（），它有效地限制了带电缺陷的移动。这些研究结果表明，Na5.5 具有巨大的应用潜力，并为了解铅基 AFE 材料的内部缺陷提供了启示。
{"title":"Modifying the high‐temperature dielectric properties of PLZT antiferroelectric ceramics by donor‒acceptor codoping","authors":"Linhai Li, Yongxin Zhou, Xuefeng Chen, Genshui Wang","doi":"10.1111/jace.20045","DOIUrl":"https://doi.org/10.1111/jace.20045","url":null,"abstract":"(Pb,La)(Zr,Ti)O<jats:sub>3</jats:sub> antiferroelectric (AFE) ceramics have attracted considerable interest due to their high‐energy storage density and numerous field‐induced phase transitions. However, the positional equilibrium of the A‐site and B‐site is typically maintained without considering that heterovalent doping of La<jats:sup>3+</jats:sup> can induce defects within the material, leading to high‐temperature leakage conduction. In this work, we introduced the acceptor ion Na<jats:sup>+</jats:sup> at the A‐site simultaneously and designed Pb<jats:sub>0.9175–0.5</jats:sub><jats:italic><jats:sub>x</jats:sub></jats:italic>La<jats:sub>0.055</jats:sub>Na<jats:italic><jats:sub>x</jats:sub></jats:italic>Zr<jats:sub>0.975</jats:sub>Ti<jats:sub>0.025</jats:sub>O<jats:sub>3</jats:sub> (<jats:italic>x </jats:italic>= 0.01, 0.03, 0.055, 0.07, 0.10) AFE ceramics. The dielectric properties of these ceramics exhibited a consistent pattern of improvement followed by deterioration as the content of Na<jats:sup>+</jats:sup> increased. Notably, when <jats:italic>x </jats:italic>= 0.055 (Na5.5), the AFE ceramic demonstrated superior high‐temperature frequency stability with negligible leakage conduction. Impedance spectroscopy analysis suggested that Na5.5 displays the greatest resistance and highest <jats:italic>E</jats:italic><jats:sub>dc</jats:sub>. Concurrently, the thermally stimulated depolarization current indicates that Na5.5 possesses the lowest defect concentration and the largest <jats:italic>E</jats:italic><jats:sub>a</jats:sub>. This can be attributed to the internal generation of defect dipole clusters (), which effectively restrict the movement of charged defects. These findings suggest that Na5.5 holds significant potential for application and offer insights into the understanding of internal defects in lead‐based AFE materials.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. M. Ilyas, Jamal‐Deen Musah, Siu Wing Or, Ayodeji Oladiran Awodugba
Photocatalytic degradation of pollutants using nanoparticles presents a promising method globally. However, effectively harnessing light absorption while mitigating recombination and nanoparticle agglomeration remains challenging. Here, we explore the synthesis and characterization of zinc oxide nanoparticles for photocatalytic dye removal in water. The ZnO catalyst, controlled by impurity amount, is developed, demonstrating a notable impact on photolytic performance. Various zinc precursors, namely, zinc acetate, zinc sulfate, zinc nitrate, and zinc chloride, were used in the precipitation technique. Optical characterization showed distinct band transitions and UV‐dominant absorption peaks, indicating the presence of different impurities in each precursor. Photocatalytic performance is assessed using Rhodamine B decomposition with the sample prepared from zinc acetate, demonstrating enhanced photocatalytic activity attributed to its larger surface area, surface defects, and superior morphology, enabling efficient organic pollutant degradation. Oxygen vacancies aid in charge carrier separation, crucial for effective photocatalysis. The material's intense interaction with pollutants and a high photocurrent density of 5.18 µAcm−2 highlight superior electron–hole pair separation capabilities influenced by morphology and impurity‐generated defects, significantly boosting its overall photocatalytic reaction. These findings emphasize the critical role of precursor selection in designing effective ZnO‐based photocatalysts, water treatment, and environmental remediation applications.
利用纳米粒子进行光催化降解污染物是一种前景广阔的全球性方法。然而，在有效利用光吸收的同时减轻重组和纳米粒子团聚仍然具有挑战性。在此，我们探讨了用于光催化去除水中染料的氧化锌纳米粒子的合成和表征。通过杂质量控制的氧化锌催化剂的开发，证明了其对光解性能的显著影响。沉淀技术中使用了多种锌前体，即醋酸锌、硫酸锌、硝酸锌和氯化锌。光学表征显示出不同的带跃迁和紫外吸收峰，表明每种前驱体中存在不同的杂质。用醋酸锌制备的样品分解罗丹明 B 评估了光催化性能，结果表明醋酸锌的光催化活性增强，这归功于其较大的表面积、表面缺陷和优异的形貌，从而实现了高效的有机污染物降解。氧空位有助于电荷载流子分离，这对有效光催化至关重要。该材料与污染物的强烈相互作用和 5.18 µAcm-2 的高光电流密度凸显了受形态学和杂质产生的缺陷影响的卓越的电子-空穴对分离能力，从而显著促进了其整体光催化反应。这些发现强调了前驱体选择在设计有效的氧化锌光催化剂、水处理和环境修复应用中的关键作用。
{"title":"Precursor impurity‐mediated effect in the photocatalytic activity of precipitated zinc oxide","authors":"A. M. Ilyas, Jamal‐Deen Musah, Siu Wing Or, Ayodeji Oladiran Awodugba","doi":"10.1111/jace.20062","DOIUrl":"https://doi.org/10.1111/jace.20062","url":null,"abstract":"Photocatalytic degradation of pollutants using nanoparticles presents a promising method globally. However, effectively harnessing light absorption while mitigating recombination and nanoparticle agglomeration remains challenging. Here, we explore the synthesis and characterization of zinc oxide nanoparticles for photocatalytic dye removal in water. The ZnO catalyst, controlled by impurity amount, is developed, demonstrating a notable impact on photolytic performance. Various zinc precursors, namely, zinc acetate, zinc sulfate, zinc nitrate, and zinc chloride, were used in the precipitation technique. Optical characterization showed distinct band transitions and UV‐dominant absorption peaks, indicating the presence of different impurities in each precursor. Photocatalytic performance is assessed using Rhodamine B decomposition with the sample prepared from zinc acetate, demonstrating enhanced photocatalytic activity attributed to its larger surface area, surface defects, and superior morphology, enabling efficient organic pollutant degradation. Oxygen vacancies aid in charge carrier separation, crucial for effective photocatalysis. The material's intense interaction with pollutants and a high photocurrent density of 5.18 µAcm<jats:sup>−2</jats:sup> highlight superior electron–hole pair separation capabilities influenced by morphology and impurity‐generated defects, significantly boosting its overall photocatalytic reaction. These findings emphasize the critical role of precursor selection in designing effective ZnO‐based photocatalysts, water treatment, and environmental remediation applications.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhiyi Jiang, Yong Zheng, Xiangyu Xu, Bo Li, Min Yang, Hao Wu, Yijie Zhao, Xuepeng Lu
Herein, using pre‐granulation method and subsequent vacuum sintering, cellular Ti(C,N)‐based cermets with various particle sizes of hard phase in agglomerates were prepared. As the particle sizes of added Ti(C,N) powders decreased, the interface between the matrix and agglomerates developed into clear and the number of abnormally grown grains decreased. The original shape of the agglomerates was maintained most completely and formed the most obvious cellular structure with the matrix in cermets sintered at 1420°C. Combined with the fractal dimension, the fracture behavior of cellular cermets was comprehensively analyzed to confirm the changes of mechanical properties. From cermet A to cermet D, the proportion of transgranular fracture in the matrix reduced, and intergranular fracture and tearing ridge within the agglomerates could be more clearly observed. Crack propagation exhibited additional crack deflection and bridging close to the interface, which consumed considerable amount of fracture energy. Furthermore, the fractal dimension of the fracture morphology and crack propagation path of cermet C reached a maximum indicating that the fracture behavior was extremely complex and irregular, resulting in excellent strength and toughness. The wear behaviors of cermets were analyzed at both room and high temperature, respectively. The wear rates of cellular cermets greatly reduced because the binder phase with large mean free path in the agglomerates was difficult to be squeezed out and the hard phase was hard to fall off. Overall, the cellular cermet C demonstrated the appreciably comprehensive mechanical properties and excellent wear resistance.
本文采用预制粒法和随后的真空烧结法制备了团聚体中硬质相粒径不同的蜂窝状钛（C,N）基金属陶瓷。随着添加的 Ti（C，N）粉末粒度的减小，基体和团聚体之间的界面变得清晰，异常生长的晶粒数量减少。在 1420°C 烧结的金属陶瓷中，团聚体的原始形状保持得最完整，并与基体形成了最明显的蜂窝状结构。结合分形维度，全面分析了蜂窝状金属陶瓷的断裂行为，证实了其力学性能的变化。从金属陶瓷 A 到金属陶瓷 D，基体中跨晶断裂的比例降低，晶间断裂和团聚体内部的撕裂脊更为明显。裂纹的扩展在靠近界面处表现出额外的裂纹偏转和桥接，这消耗了大量的断裂能量。此外，金属陶瓷 C 的断裂形态和裂纹扩展路径的分形维数达到最大值，表明其断裂行为极其复杂且不规则，因而具有极佳的强度和韧性。分别在室温和高温下分析了金属陶瓷的磨损行为。由于团聚体中平均自由路径较大的粘合剂相难以被挤出，而硬质相难以脱落，因此蜂窝状金属陶瓷的磨损率大大降低。总体而言，蜂窝金属陶瓷 C 具有明显的综合机械性能和优异的耐磨性。
{"title":"Microstructure, fracture behavior, and wear resistance of cellular Ti(C,N)‐based cermets","authors":"Zhiyi Jiang, Yong Zheng, Xiangyu Xu, Bo Li, Min Yang, Hao Wu, Yijie Zhao, Xuepeng Lu","doi":"10.1111/jace.20046","DOIUrl":"https://doi.org/10.1111/jace.20046","url":null,"abstract":"Herein, using pre‐granulation method and subsequent vacuum sintering, cellular Ti(C,N)‐based cermets with various particle sizes of hard phase in agglomerates were prepared. As the particle sizes of added Ti(C,N) powders decreased, the interface between the matrix and agglomerates developed into clear and the number of abnormally grown grains decreased. The original shape of the agglomerates was maintained most completely and formed the most obvious cellular structure with the matrix in cermets sintered at 1420°C. Combined with the fractal dimension, the fracture behavior of cellular cermets was comprehensively analyzed to confirm the changes of mechanical properties. From cermet A to cermet D, the proportion of transgranular fracture in the matrix reduced, and intergranular fracture and tearing ridge within the agglomerates could be more clearly observed. Crack propagation exhibited additional crack deflection and bridging close to the interface, which consumed considerable amount of fracture energy. Furthermore, the fractal dimension of the fracture morphology and crack propagation path of cermet C reached a maximum indicating that the fracture behavior was extremely complex and irregular, resulting in excellent strength and toughness. The wear behaviors of cermets were analyzed at both room and high temperature, respectively. The wear rates of cellular cermets greatly reduced because the binder phase with large mean free path in the agglomerates was difficult to be squeezed out and the hard phase was hard to fall off. Overall, the cellular cermet C demonstrated the appreciably comprehensive mechanical properties and excellent wear resistance.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141929462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maidina Muhetaer, Ling Dong, Yu Wang, Yuhua Ma, Hong Du
It is of great significance to design photoelectrodes with high carrier separation and transport efficiency in photocatalytic water separation systems. In this study, we used a simple electrochemical deposition method to regulate the load of co‐catalyst CoP on TiO2 nanorods to improve the photoelectrochemical properties. The photocurrent density of TiO2/CoP (20) photoanode at 1.23 V increases to 1.57 mA/cm2, which is 3.4 times that of original TiO2. Long‐term photoelectrolysis reveals that this electrode has excellent stability. Mechanistic studies support the role of CoP nanoparticles in improving photoelectrochemical property and imply that the excellent photoelectrochemical property of TiO2/CoP photoanode is mainly ascribed to the suppress of surface photogenerated electrons and holes recombination due to the construction of built‐in electric field between TiO2 and CoP.
{"title":"CoP electrodeposited on TiO2 nanorod arrays as photoanode for enhanced photoelectrochemical water splitting","authors":"Maidina Muhetaer, Ling Dong, Yu Wang, Yuhua Ma, Hong Du","doi":"10.1111/jace.20049","DOIUrl":"https://doi.org/10.1111/jace.20049","url":null,"abstract":"It is of great significance to design photoelectrodes with high carrier separation and transport efficiency in photocatalytic water separation systems. In this study, we used a simple electrochemical deposition method to regulate the load of co‐catalyst CoP on TiO<jats:sub>2</jats:sub> nanorods to improve the photoelectrochemical properties. The photocurrent density of TiO<jats:sub>2</jats:sub>/CoP (20) photoanode at 1.23 V increases to 1.57 mA/cm<jats:sup>2</jats:sup>, which is 3.4 times that of original TiO<jats:sub>2</jats:sub>. Long‐term photoelectrolysis reveals that this electrode has excellent stability. Mechanistic studies support the role of CoP nanoparticles in improving photoelectrochemical property and imply that the excellent photoelectrochemical property of TiO<jats:sub>2</jats:sub>/CoP photoanode is mainly ascribed to the suppress of surface photogenerated electrons and holes recombination due to the construction of built‐in electric field between TiO<jats:sub>2</jats:sub> and CoP.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anuraag Gaddam, Gustavo Galleani, Vitor de Lima Reis, Andrea S. S. de Camargo, Hellmut Eckert
Gallium fluoride phosphate glasses feature low refractive index, high energy radiation resistance, wide transmission range, and favorable emission characteristics of rare‐earth dopants. For the development of optimized glass compositions, a fundamental understanding of these properties in terms of glass structure is sought. We report nuclear magnetic resonance (NMR) structural studies of glasses in the system xGa(PO3)3–(40 − x)GaF3–20BaF2–20ZnF2–20SrF2 (x = 5, 10, 15, 20, and 25 mol%). 31P NMR results with 71Ga recoupling show that the network structure is dominated by P–O–Ga linkages, and no P–O–P linkages exist. 71Ga NMR results show that Ga is mainly six‐coordinated featuring a mixed fluoride/phosphate coordination. Quantitative estimates of this ligand distribution around gallium were obtained by 71Ga{31P} spin echo double resonance (REDOR) measurements. Photophysical properties suggest changes in the Eu(III) ligand distribution toward a fluoride‐dominated environment at low P/F ratio while the glass network is largely sustained by bridging oxygen atoms via P–O–Ga linkages.
{"title":"Structural characterization of gallium fluoride phosphate glasses by advanced solid‐state NMR methods and correlation with photophysical properties","authors":"Anuraag Gaddam, Gustavo Galleani, Vitor de Lima Reis, Andrea S. S. de Camargo, Hellmut Eckert","doi":"10.1111/jace.20051","DOIUrl":"https://doi.org/10.1111/jace.20051","url":null,"abstract":"Gallium fluoride phosphate glasses feature low refractive index, high energy radiation resistance, wide transmission range, and favorable emission characteristics of rare‐earth dopants. For the development of optimized glass compositions, a fundamental understanding of these properties in terms of glass structure is sought. We report nuclear magnetic resonance (NMR) structural studies of glasses in the system <jats:italic>x</jats:italic>Ga(PO<jats:sub>3</jats:sub>)<jats:sub>3</jats:sub>–(40 − <jats:italic>x</jats:italic>)GaF<jats:sub>3</jats:sub>–20BaF<jats:sub>2</jats:sub>–20ZnF<jats:sub>2</jats:sub>–20SrF<jats:sub>2</jats:sub> (<jats:italic>x</jats:italic> = 5, 10, 15, 20, and 25 mol%). <jats:sup>31</jats:sup>P NMR results with <jats:sup>71</jats:sup>Ga recoupling show that the network structure is dominated by P–O–Ga linkages, and no P–O–P linkages exist. <jats:sup>71</jats:sup>Ga NMR results show that Ga is mainly six‐coordinated featuring a mixed fluoride/phosphate coordination. Quantitative estimates of this ligand distribution around gallium were obtained by <jats:sup>71</jats:sup>Ga{<jats:sup>31</jats:sup>P} spin echo double resonance (REDOR) measurements. Photophysical properties suggest changes in the Eu(III) ligand distribution toward a fluoride‐dominated environment at low P/F ratio while the glass network is largely sustained by bridging oxygen atoms via P–O–Ga linkages.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phosphor ceramics are considered to be promising color converters for high‐brightness laser lighting. However, current laser lighting usually suffers from a poor color rendering index (Ra ∼70) when using a single‐structured phosphor ceramic, due to the deficiencies in the cyan‐green and red components of the luminescence spectra. In this study, a series of Ca3Sc2Si3O12:Ce3+, Mn2+ (CSS:Ce3+, Mn2+) phosphor ceramics were prepared for the first time using a solid‐state reaction method. Based on the efficient energy transfer from Ce3+ to Mn2+ (with an energy transfer efficiency of ∼33.3%), these ceramics exhibit three distinct emission peaks appearing at 505, 580, and 680 nm, covering the cyan‐green, yellow, and deep red‐light regions, respectively. Additionally, the ceramics display excellent thermal stability, with a thermal quenching temperature (T0.5) exceeding 160°C. Finally, a laser lighting source was constructed by combining the CSS:Ce3+, Mn2+ ceramic with a blue laser diode. By optimizing the Mn2+ concentration, a tunable color from cyan‐green to white was achieved, and the resulting Ra and luminous efficacy of the white light were 86 and 65 lm/W, respectively. These results demonstrate that the CSS:Ce3+, Mn2+ phosphor ceramic is an excellent color converter for full‐color laser lighting.
{"title":"Ca3Sc2Si3O12:Ce3+, Mn2+ phosphor ceramic: A promising color converter for full‐color laser lighting","authors":"Huajun Wu, Han Xiao, Guo‐Hui Pan, Zhendong Hao, Liangliang Zhang, Hao Wu, Jiahua Zhang","doi":"10.1111/jace.20048","DOIUrl":"https://doi.org/10.1111/jace.20048","url":null,"abstract":"Phosphor ceramics are considered to be promising color converters for high‐brightness laser lighting. However, current laser lighting usually suffers from a poor color rendering index (Ra ∼70) when using a single‐structured phosphor ceramic, due to the deficiencies in the cyan‐green and red components of the luminescence spectra. In this study, a series of Ca<jats:sub>3</jats:sub>Sc<jats:sub>2</jats:sub>Si<jats:sub>3</jats:sub>O<jats:sub>12</jats:sub>:Ce<jats:sup>3+</jats:sup>, Mn<jats:sup>2+</jats:sup> (CSS:Ce<jats:sup>3+</jats:sup>, Mn<jats:sup>2+</jats:sup>) phosphor ceramics were prepared for the first time using a solid‐state reaction method. Based on the efficient energy transfer from Ce<jats:sup>3+</jats:sup> to Mn<jats:sup>2+</jats:sup> (with an energy transfer efficiency of ∼33.3%), these ceramics exhibit three distinct emission peaks appearing at 505, 580, and 680 nm, covering the cyan‐green, yellow, and deep red‐light regions, respectively. Additionally, the ceramics display excellent thermal stability, with a thermal quenching temperature (<jats:italic>T</jats:italic><jats:sub>0.5</jats:sub>) exceeding 160°C. Finally, a laser lighting source was constructed by combining the CSS:Ce<jats:sup>3+</jats:sup>, Mn<jats:sup>2+</jats:sup> ceramic with a blue laser diode. By optimizing the Mn<jats:sup>2+</jats:sup> concentration, a tunable color from cyan‐green to white was achieved, and the resulting Ra and luminous efficacy of the white light were 86 and 65 lm/W, respectively. These results demonstrate that the CSS:Ce<jats:sup>3+</jats:sup>, Mn<jats:sup>2+</jats:sup> phosphor ceramic is an excellent color converter for full‐color laser lighting.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141933068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yanxue Yue, Weiyu Zhu, Alhadi Ishag, Bo Zhang, Yubing Sun
The natural clay mineral was activated using the acid treatment under ultrasonic conditions to improve its adsorption performance. The acid‐activated clay (AAC) was investigated to remove Cr(VI) from wasted lubricant and U(VI) from aqueous solution by batch, spectroscopy, and modeling. Batch experiments showed that the isotherms and adsorption kinetics of Cr(VI)/U(VI) on AAC were satisfactorily followed by Frenudlich and the pseudo‐second‐order model, respectively. The decreased adsorption of U(VI) on AAC with the increase of ion strength indicated the outer surface complexation of U(VI) on AAC. The interaction mechanism of Cr(VI)/U(VI) on AAC was demonstrated to be surface complexation by oxygenated functional groups (e.g., hydroxyl) according to X‐ray photoelectron spectroscopy (XPS) analysis. According to fitting of surface complexation models using three approaches, the adsorption of U(VI) on AAC at different pH can be better fitted by the double‐layer model compared to the constant‐capacitance model and triple‐layer model. These findings are great important for the application of acid activated clay in the removal of heavy metals and radionuclides from the environment.
{"title":"Ultrasonic‐assisted activation of clay for efficient removal of U(VI) and Cr(VI)","authors":"Yanxue Yue, Weiyu Zhu, Alhadi Ishag, Bo Zhang, Yubing Sun","doi":"10.1111/jace.20015","DOIUrl":"https://doi.org/10.1111/jace.20015","url":null,"abstract":"The natural clay mineral was activated using the acid treatment under ultrasonic conditions to improve its adsorption performance. The acid‐activated clay (AAC) was investigated to remove Cr(VI) from wasted lubricant and U(VI) from aqueous solution by batch, spectroscopy, and modeling. Batch experiments showed that the isotherms and adsorption kinetics of Cr(VI)/U(VI) on AAC were satisfactorily followed by Frenudlich and the pseudo‐second‐order model, respectively. The decreased adsorption of U(VI) on AAC with the increase of ion strength indicated the outer surface complexation of U(VI) on AAC. The interaction mechanism of Cr(VI)/U(VI) on AAC was demonstrated to be surface complexation by oxygenated functional groups (e.g., hydroxyl) according to X‐ray photoelectron spectroscopy (XPS) analysis. According to fitting of surface complexation models using three approaches, the adsorption of U(VI) on AAC at different pH can be better fitted by the double‐layer model compared to the constant‐capacitance model and triple‐layer model. These findings are great important for the application of acid activated clay in the removal of heavy metals and radionuclides from the environment.","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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