Pub Date : 2024-11-20DOI: 10.1016/j.diamond.2024.111813
S. Jacob Rosarian Joy, D. Rajan Babu
To improve microwave absorption in the X-band frequency range (8.2–12.4 GHz), this work describes the creation and characterization of a new composite material made of graphitic carbon nitride (g-C₃N₄) and strontium hexaferrite (SrFe₁₂O₁₉). Easy manufacturing techniques were used to ensure uniformity and the best possible distribution of both components in the composite. Using the vector network analyzer, microwave absorption characteristics were examined, with reflection loss (RL) serving as the primary performance metric. The composite material exhibited remarkable absorption of microwaves, as evidenced by its considerable reflection loss of −59.22 dB at a thickness of 4 mm. It was discovered that the main factor influencing this improved performance was the synergistic interaction between strontium hexaferrite and graphitic carbon nitride.
为了改善 X 波段频率范围（8.2-12.4 GHz）的微波吸收，这项研究描述了一种由石墨氮化碳（g-C₃N₄）和六铁锶（SrFe₁₂O₁₉）制成的新型复合材料的制作和特性分析。为确保两种成分在复合材料中的均匀性和最佳分布，采用了简便的制造技术。使用矢量网络分析仪检测了微波吸收特性，主要性能指标为反射损耗（RL）。复合材料对微波的吸收效果显著，在厚度为 4 毫米时，其反射损耗高达 -59.22 dB。研究发现，影响这种性能改善的主要因素是六价铁锶和氮化石墨碳之间的协同作用。
{"title":"Study of microwave absorption properties of strontium hexaferrite (SrFe12O19) and graphitic‑carbon nitride (g-C3N4) composite in X-band range","authors":"S. Jacob Rosarian Joy, D. Rajan Babu","doi":"10.1016/j.diamond.2024.111813","DOIUrl":"10.1016/j.diamond.2024.111813","url":null,"abstract":"<div><div>To improve microwave absorption in the X-band frequency range (8.2–12.4 GHz), this work describes the creation and characterization of a new composite material made of graphitic carbon nitride (g-C₃N₄) and strontium hexaferrite (SrFe₁₂O₁₉). Easy manufacturing techniques were used to ensure uniformity and the best possible distribution of both components in the composite. Using the vector network analyzer, microwave absorption characteristics were examined, with reflection loss (R<sub>L</sub>) serving as the primary performance metric. The composite material exhibited remarkable absorption of microwaves, as evidenced by its considerable reflection loss of −59.22 dB at a thickness of 4 mm. It was discovered that the main factor influencing this improved performance was the synergistic interaction between strontium hexaferrite and graphitic carbon nitride.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111813"},"PeriodicalIF":4.3,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702896","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}
Pub Date : 2024-11-20DOI: 10.1016/j.diamond.2024.111784
Sevgi Ateş , Evrim Baran Aydın
In the present study, the TiB2, MgB2/ Graphene (GRP)/PLA and TiB2, MgB2/Carbon Nanofiber (CNF)/PLA 3D-printed electrodes were fabricated via the Fused Deposition Modeling (FDM) technique. The hydrogen Evolution Reaction (HER) performance of 3D electrodes was studied using electrochemical impedance spectroscopy (EIS) and cathodic polarization analysis methods in 1 M KOH media. The EIS measurement results showed that the total resistance values were significantly reduced due to the addition of GRP and CNF to TiB2/PLA and MgB2/PLA 3D electrodes. In addition, the increase in current density with the addition of GRP and CNF to the 3D electrodes from the cathodic polarization curves supported the EIS measurement results. Moreover, a new activation method without using solvent was applied as different from the literature, to enhance the conductivity of 3D electrodes. The activation process was performed by implementing 50 cycles in 1 M KOH solution with the cyclic voltammetry method. As a result, with this study, both the synergistic effect of multiple composites and the application of the activation method have increased the HER efficiency of the 3D electrocatalyst. Thus, 3D electrocatalysts have been introduced to the energy application field.
本研究通过熔融沉积建模（FDM）技术制造了 TiB2、MgB2/石墨烯（GRP）/PLA 和 TiB2、MgB2/碳纳米纤维（CNF）/PLA 三维打印电极。在 1 M KOH 介质中，使用电化学阻抗谱（EIS）和阴极极化分析方法研究了三维电极的氢进化反应（HER）性能。EIS 测量结果表明，在 TiB2/PLA 和 MgB2/PLA 三维电极中添加 GRP 和 CNF 后，总电阻值显著降低。此外，从阴极极化曲线来看，在三维电极中添加 GRP 和 CNF 后，电流密度增加，这也支持了 EIS 测量结果。此外，为了提高三维电极的导电性，还采用了一种与文献不同的不使用溶剂的新活化方法。活化过程是在 1 M KOH 溶液中用循环伏安法进行 50 个循环。因此，通过这项研究，多种复合材料的协同效应和活化方法的应用都提高了三维电催化剂的 HER 效率。因此，三维电催化剂已被引入能源应用领域。
{"title":"Hydrogen evolution reaction activity of 3D-printed TiB2 and MgB2 matrix reinforced with graphene and carbon nanofiber in alkaline media","authors":"Sevgi Ateş , Evrim Baran Aydın","doi":"10.1016/j.diamond.2024.111784","DOIUrl":"10.1016/j.diamond.2024.111784","url":null,"abstract":"<div><div>In the present study, the TiB<sub>2,</sub> MgB<sub>2</sub>/ Graphene (GRP)/PLA and TiB<sub>2</sub>, MgB<sub>2</sub>/Carbon Nanofiber (CNF)/PLA 3D-printed electrodes were fabricated via the Fused Deposition Modeling (FDM) technique. The hydrogen Evolution Reaction (HER) performance of 3D electrodes was studied using electrochemical impedance spectroscopy (EIS) and cathodic polarization analysis methods in 1 M KOH media. The EIS measurement results showed that the total resistance values <!--> <!-->were significantly reduced due to the addition of GRP and CNF to TiB<sub>2</sub>/PLA and MgB<sub>2</sub>/PLA 3D electrodes. In addition, the increase in current density with the addition of GRP and CNF to the 3D electrodes from the cathodic polarization curves supported the EIS measurement results. Moreover, a new activation method without using solvent was applied as different from the literature, to enhance the conductivity of 3D electrodes. The activation process was performed by implementing 50 cycles in 1 M KOH solution with the cyclic voltammetry method. As a result, with this study, both the synergistic effect of multiple composites and the application of the activation method have increased the HER efficiency of the 3D electrocatalyst. Thus, 3D electrocatalysts have been introduced to the energy application field.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111784"},"PeriodicalIF":4.3,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702886","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}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111809
Xiaojing Tang, Huaxu Song, Junqi Liang, Mengke Wu, Yuanhao Zhang, Yishun Xie, Qihao Tang, Lin Qin, Xin Fan
Carbon aerogels derived from biomass are eco-friendly, renewable, and cost-effective, making them promising electrode materials for supercapacitors. In this study, N-doped honeycomb-like carbon aerogels were synthesized from cellulose extracted from bamboo waste, through a self-gelation process in NaOH/KOH/urea, followed by freeze-drying and a synchronized carbonization-activation method. The N-doping significantly improved surface wettability and introduced additional pseudocapacitance via the formation of functional groups. The effect of activation temperature on pore structure and electrochemical performance was thoroughly investigated. The optimized carbon aerogel (CA-600) exhibited a large specific surface area of 1022.53 m2 g−1 and a high specific capacitance of 294.2 F g−1 at 0.2 A g−1. The CA-600//CA-600 device delivered an energy density of 8.8 Wh kg−1 at a power density of 5000 W kg−1, with a capacitance retention of 90.7 % after 10,000 cycles. These results demonstrate the potential of carbon aerogel derived from bamboo waste as sustainable materials for energy storage applications, offering a promising pathway toward eco-friendly supercapacitor development.
从生物质中提取的碳气凝胶具有生态友好、可再生和成本效益高等特点，因此是超级电容器的理想电极材料。本研究利用从竹子废弃物中提取的纤维素，通过在 NaOH/KOH/ 尿素中的自凝胶过程，再经过冷冻干燥和同步碳化-活化方法，合成了掺杂 N 的蜂窝状碳气凝胶。N掺杂大大改善了表面润湿性，并通过官能团的形成引入了额外的假电容。此外，还深入研究了活化温度对孔隙结构和电化学性能的影响。优化后的碳气凝胶（CA-600）具有 1022.53 m2 g-1 的大比表面积和 294.2 F g-1 的高比电容（0.2 A g-1）。在功率密度为 5000 W kg-1 时，CA-600//CA-600 器件的能量密度为 8.8 Wh kg-1，经过 10,000 次循环后，电容保持率为 90.7%。这些结果证明了从竹子废弃物中提取的碳气凝胶作为可持续材料在储能应用方面的潜力，为生态友好型超级电容器的开发提供了一条前景广阔的途径。
{"title":"Synchronous N-doping and activation of carbon aerogels derived from bamboo waste for high-performance supercapacitors","authors":"Xiaojing Tang, Huaxu Song, Junqi Liang, Mengke Wu, Yuanhao Zhang, Yishun Xie, Qihao Tang, Lin Qin, Xin Fan","doi":"10.1016/j.diamond.2024.111809","DOIUrl":"10.1016/j.diamond.2024.111809","url":null,"abstract":"<div><div>Carbon aerogels derived from biomass are eco-friendly, renewable, and cost-effective, making them promising electrode materials for supercapacitors. In this study, N-doped honeycomb-like carbon aerogels were synthesized from cellulose extracted from bamboo waste, through a self-gelation process in NaOH/KOH/urea, followed by freeze-drying and a synchronized carbonization-activation method. The N-doping significantly improved surface wettability and introduced additional pseudocapacitance via the formation of functional groups. The effect of activation temperature on pore structure and electrochemical performance was thoroughly investigated. The optimized carbon aerogel (CA-600) exhibited a large specific surface area of 1022.53 m<sup>2</sup> g<sup>−1</sup> and a high specific capacitance of 294.2 F g<sup>−1</sup> at 0.2 A g<sup>−1</sup>. The CA-600//CA-600 device delivered an energy density of 8.8 Wh kg<sup>−1</sup> at a power density of 5000 W kg<sup>−1</sup>, with a capacitance retention of 90.7 % after 10,000 cycles. These results demonstrate the potential of carbon aerogel derived from bamboo waste as sustainable materials for energy storage applications, offering a promising pathway toward eco-friendly supercapacitor development.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111809"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702885","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}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111798
G Suganya , M Arivanandhan , G Kalpana
Supercapattery technology focuses on high specific capacity with both high energy density and power density. In the present work, the electrochemical performance of Graphene quantum dots (GQDs) is compared with graphene oxide (GO). GO is synthesized by the modified Hummer's method. Less than 5 nm size of GQDs are synthesized by a facile chemical cutting method. High frequency vibrational mode of sp-sp2 bonded carbon at 2198 cm−1 is revealed from Raman analysis. The energy gap of GQDs of different sizes was calculated using the Quantum Espresso code based on Plane-Wave Self-Consistent Field (PWSCF). The forbidden gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels with the size of the GQDs cluster. The electrochemical results show that GQDs exhibit pseudocapacitor behavior with high specific capacity and energy density of 1516.7C/g and 425.9 Whkg−1 respectively at current density of 4 A/g. This is very high compared to the electric double layer capacitor (EDLC) behavior (115C/g) of GO. These results illustrate enhanced electrochemical performance, electrical conductivity and ion transport rate implying that the material can facilitate the movement of ions within the device, allowing for fast charging and discharging.
{"title":"Giant energy storage capacity of graphene quantum dots prepared by facile method","authors":"G Suganya , M Arivanandhan , G Kalpana","doi":"10.1016/j.diamond.2024.111798","DOIUrl":"10.1016/j.diamond.2024.111798","url":null,"abstract":"<div><div>Supercapattery technology focuses on high specific capacity with both high energy density and power density. In the present work, the electrochemical performance of Graphene quantum dots (GQDs) is compared with graphene oxide (GO). GO is synthesized by the modified Hummer's method. Less than 5 nm size of GQDs are synthesized by a facile chemical cutting method. High frequency vibrational mode of <em>sp</em>-<em>sp</em><sup>2</sup> bonded carbon at 2198 cm<sup>−1</sup> is revealed from Raman analysis. The energy gap of GQDs of different sizes was calculated using the Quantum Espresso code based on Plane-Wave Self-Consistent Field (PWSCF). The forbidden gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels with the size of the GQDs cluster. The electrochemical results show that GQDs exhibit pseudocapacitor behavior with high specific capacity and energy density of 1516.7C/g and 425.9 Whkg<sup>−1</sup> respectively at current density of 4 A/g. This is very high compared to the electric double layer capacitor (EDLC) behavior (115C/g) of GO. These results illustrate enhanced electrochemical performance, electrical conductivity and ion transport rate implying that the material can facilitate the movement of ions within the device, allowing for fast charging and discharging.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111798"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702889","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}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111802
W.Q. Guo , J.C. Xu , B. Hong , Y.B. Han , X.L. Peng , J. Li , H.W. Chen , S. Qiu , X.Q. Wang
SmFeO3/Fe@carbon nanotubes (CNTs) nanocomposites are synthesized in-situ using SmFeO3 as catalysts and C2H2 as carbon sources with CVD method. CNTs are grown from Fe nanoparticles on SmFeO3 surface by tip-growth mechanism, and CNTs content increases with the increasing CVD time. In-situ synthesized Fe and CNTs greatly enhances magnetic and dielectric properties, leading to the excellent microwave absorption performance of SmFeO3/Fe@CNTs nanocomposites. Among them, SmFeO3–4 (CVD for 4 min) exhibits the best microwave absorption capacities with a minimum reflection loss of −50.16 dB at 11.84 GHz and a broad effective absorption bandwidth of 3.92 GHz at a thin thickness of 2.0 mm. The optimized impedance matching ensures SmFeO3/Fe@CNTs nanocomposites capture almost incident microwaves, and then attenuates microwaves through dielectric losses and magnetic losses. The conductive CNTs and higher specific surface area leads to higher dipole polarization, interfacial polarization, and conduction loss, while magnetic Fe nanoparticles result in the natural resonance, exchange resonance, and eddy current loss. Finally, the incident microwaves travelled through the different components of SmFeO3/Fe@CNTs nanocomposites leads to the microwaves attenuation through multiple reflections and scattering.
{"title":"In-situ synthesis of SmFeO3/Fe@CNTs nanocomposites with optimized impedance matching for strong and broadband microwave absorption","authors":"W.Q. Guo , J.C. Xu , B. Hong , Y.B. Han , X.L. Peng , J. Li , H.W. Chen , S. Qiu , X.Q. Wang","doi":"10.1016/j.diamond.2024.111802","DOIUrl":"10.1016/j.diamond.2024.111802","url":null,"abstract":"<div><div>SmFeO<sub>3</sub>/Fe@carbon nanotubes (CNTs) nanocomposites are synthesized in-situ using SmFeO<sub>3</sub> as catalysts and C<sub>2</sub>H<sub>2</sub> as carbon sources with CVD method. CNTs are grown from Fe nanoparticles on SmFeO<sub>3</sub> surface by tip-growth mechanism, and CNTs content increases with the increasing CVD time. In-situ synthesized Fe and CNTs greatly enhances magnetic and dielectric properties, leading to the excellent microwave absorption performance of SmFeO<sub>3</sub>/Fe@CNTs nanocomposites. Among them, SmFeO<sub>3</sub>–4 (CVD for 4 min) exhibits the best microwave absorption capacities with a minimum reflection loss of −50.16 dB at 11.84 GHz and a broad effective absorption bandwidth of 3.92 GHz at a thin thickness of 2.0 mm. The optimized impedance matching ensures SmFeO<sub>3</sub>/Fe@CNTs nanocomposites capture almost incident microwaves, and then attenuates microwaves through dielectric losses and magnetic losses. The conductive CNTs and higher specific surface area leads to higher dipole polarization, interfacial polarization, and conduction loss, while magnetic Fe nanoparticles result in the natural resonance, exchange resonance, and eddy current loss. Finally, the incident microwaves travelled through the different components of SmFeO<sub>3</sub>/Fe@CNTs nanocomposites leads to the microwaves attenuation through multiple reflections and scattering.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111802"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702891","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}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111805
Rémi Gillet, Ingrid Stenger, Subodh Kumar Gautam, Christophe Arnold, Estelle Loire, François Jomard, Julien Barjon, Marie-Amandine Pinault-Thaury
n-type diamond substrates are highly desired for diamond electronics and quantum technology based on NV centers. In this work, we investigate the high growth rates obtained using plasma with high-power densities in a commercial bell-jar chemical vapor deposition reactor equipped with a gas panel for diamond doping with phosphorus impurities. We evidence that the diamond growth rate is increased by adding phosphorus precursor in the gas mixture, up to 21.6 μm/h. We found conditions for growing extremely thick (up 580 μm) phosphorus doped (100) diamond homoepilayers keeping a n-type character as shown by optical spectroscopy. From such films we succeed in slicing a free-standing phosphorus-doped diamond plate, showing the feasibility of n-type diamond substrate fabrication for further use in optoelectronics and quantum devices.
n 型金刚石衬底是基于 NV 中心的金刚石电子器件和量子技术所亟需的。在这项工作中，我们研究了在商用钟罩式化学气相沉积反应器中使用高功率密度等离子体获得的高生长率，该反应器配备了一个气体面板，用于在金刚石中掺入磷杂质。我们证明，在气体混合物中添加磷前驱体可提高金刚石的生长速度，最高可达 21.6 μm/h。我们找到了生长极厚（高达 580 μm）掺磷（100）金刚石均质薄膜的条件，并通过光学光谱显示了其 n 型特性。从这些薄膜中，我们成功地切片出了一块独立的掺磷金刚石板，显示了 n 型金刚石衬底制造的可行性，可进一步用于光电子和量子设备。
{"title":"Free-standing n-type phosphorus-doped diamond","authors":"Rémi Gillet, Ingrid Stenger, Subodh Kumar Gautam, Christophe Arnold, Estelle Loire, François Jomard, Julien Barjon, Marie-Amandine Pinault-Thaury","doi":"10.1016/j.diamond.2024.111805","DOIUrl":"10.1016/j.diamond.2024.111805","url":null,"abstract":"<div><div>n-type diamond substrates are highly desired for diamond electronics and quantum technology based on NV centers. In this work, we investigate the high growth rates obtained using plasma with high-power densities in a commercial bell-jar chemical vapor deposition reactor equipped with a gas panel for diamond doping with phosphorus impurities. We evidence that the diamond growth rate is increased by adding phosphorus precursor in the gas mixture, up to 21.6 μm/h. We found conditions for growing extremely thick (up 580 μm) phosphorus doped (100) diamond homoepilayers keeping a n-type character as shown by optical spectroscopy. From such films we succeed in slicing a free-standing phosphorus-doped diamond plate, showing the feasibility of n-type diamond substrate fabrication for further use in optoelectronics and quantum devices.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111805"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111807
Qiang Yue , Takayoshi Yokoya , Yuji Muraoka
Spin-constrained first-principles calculations were performed to assess amorphous carbon systems having a density of 5.24, 5.46 or 5.63 g/cm3. The liquid quenching method was employed to produce suitable amorphous structures, and analyses of radial distribution functions, distributions of local magnetic moments and partial electronic densities of states were carried out. The system with a magnetic moment of 0.4 μB/atom and density of 5.63 g/cm3 was found to possess a high proportion (approximately 72.1 %) of sp3 hybridized carbon atoms. This result was in good agreement with recent experimental evaluations of ferromagnetic Q‑carbon. The simulations also indicated that unpaired electrons will be present in two types of sp2 hybridized carbon atoms and that these electrons are largely responsible for ferromagnetism in Q‑carbon. The present work provides an important starting point that will assist in understanding the nature of this material and promote the study of high-density Q‑carbon materials with novel physical properties.
{"title":"First-principles calculations concerning ferromagnetism in Q-carbon","authors":"Qiang Yue , Takayoshi Yokoya , Yuji Muraoka","doi":"10.1016/j.diamond.2024.111807","DOIUrl":"10.1016/j.diamond.2024.111807","url":null,"abstract":"<div><div>Spin-constrained first-principles calculations were performed to assess amorphous carbon systems having a density of 5.24, 5.46 or 5.63 g/cm<sup>3</sup>. The liquid quenching method was employed to produce suitable amorphous structures, and analyses of radial distribution functions, distributions of local magnetic moments and partial electronic densities of states were carried out. The system with a magnetic moment of 0.4 μ<sub>B</sub>/atom and density of 5.63 g/cm<sup>3</sup> was found to possess a high proportion (approximately 72.1 %) of sp<sup>3</sup> hybridized carbon atoms. This result was in good agreement with recent experimental evaluations of ferromagnetic Q‑carbon. The simulations also indicated that unpaired electrons will be present in two types of sp<sup>2</sup> hybridized carbon atoms and that these electrons are largely responsible for ferromagnetism in Q‑carbon. The present work provides an important starting point that will assist in understanding the nature of this material and promote the study of high-density Q‑carbon materials with novel physical properties.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111807"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702884","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}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111797
NurulHuda Shah , JinKiong Ling , Devu Bindhu , Ghufira , Izan Izwan Misnon , Chandrasekharan Nair Omanaamma Sreekala , Chun-Chen Yang , Rajan Jose
Honeycomb-shaped porous carbon (HSPC) offers unique surface properties for rapid ion transport through the bulk and hence could deliver desirable electrochemical charge storage performance; however, their fabrication is through time and cost intensive sacrificial template methods. Herein, HSPC was synthesized from a carefully selected plant component (coconut rachis) containing a dense network of phloem and xylem. The synthesized activated carbon has relatively high carbon content (>80 %), desirable textural characteristics (specific surface area ~ 1290 m2⸱g−1 and pore diameter ~ 2.0 nm), and high edge-plane fraction (ratio between relative density of edge and basal plane ~0.26). The HSPC electrodes delivered specific capacitance up to ~126 F⸱g−1 at 100 mA⸱g−1 at a potential window of 2–4 V in the HSPC//LiPF6//Li lithium metal capacitor configuration and retained ~98 % of its initial capacity after 1000 cycles with coulombic efficiency ~100 %. The performance of the device has been validated by electrochemical impedance spectroscopy before and after cycling. A postmortem analysis confirmed structural and chemical stability of the device upon cycling.
{"title":"Lithium-ion storage in honeycomb-structured biomass-derived porous carbon","authors":"NurulHuda Shah , JinKiong Ling , Devu Bindhu , Ghufira , Izan Izwan Misnon , Chandrasekharan Nair Omanaamma Sreekala , Chun-Chen Yang , Rajan Jose","doi":"10.1016/j.diamond.2024.111797","DOIUrl":"10.1016/j.diamond.2024.111797","url":null,"abstract":"<div><div>Honeycomb-shaped porous carbon (HSPC) offers unique surface properties for rapid ion transport through the bulk and hence could deliver desirable electrochemical charge storage performance; however, their fabrication is through time and cost intensive sacrificial template methods. Herein, HSPC was synthesized from a carefully selected plant component (coconut rachis) containing a dense network of phloem and xylem. The synthesized activated carbon has relatively high carbon content (>80 %), desirable textural characteristics (specific surface area ~ 1290 m<sup>2</sup>⸱g<sup>−1</sup> and pore diameter ~ 2.0 nm), and high edge-plane fraction (ratio between relative density of edge and basal plane ~0.26). The HSPC electrodes delivered specific capacitance up to ~126 F⸱g<sup>−1</sup> at 100 mA⸱g<sup>−1</sup> at a potential window of 2–4 V in the HSPC//LiPF<sub>6</sub>//Li lithium metal capacitor configuration and retained ~98 % of its initial capacity after 1000 cycles with coulombic efficiency ~100 %. The performance of the device has been validated by electrochemical impedance spectroscopy before and after cycling. A postmortem analysis confirmed structural and chemical stability of the device upon cycling.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111797"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702898","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}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111803
M.A. Guazzelli , L.H. Avanzi , V.A.P. Aguiar , A.C. Vilas-Bôas , S.G. Alberton , S.H. Masunaga , E.F. Chinaglia , K. Araki , M. Nakamura , M.M. Toyama , F.F. Ferreira , M.T. Escote , R.B.B. Santos , N.H. Medina , J.R.B. Oliveira , F. Cappuzzello , M. Cavallaro , for the NUMEN collaboration
Highly Ordered Pyrolytic Graphite (HOPG) has been extensively researched due to its chemical and physical properties that make it suitable for applications in several technologies. Its high thermal conductivity makes HOPG an excellent heat sink, a crucial characteristic for manufacturing targets used in nuclear reactions, such as those proposed by the NUMEN project. However, when subjected to different radiation sources, this material undergoes changes in its crystalline structure, which alters its intended functionality. This study examined HOPG sheets before and after exposure to a 14 MeV neutron beam. Morphological and crystallographic analyses reveal that even minor disruptions in the high atomic ordering result in modifications to its thermal properties. The results of this study are essential to establish the survival time of the HOPG used as thermal interface material to improve heat dissipation of a nuclear target to be bombarded by an intense high-energy heavy-ion beam.
{"title":"Effects of neutron radiation on the thermal conductivity of highly oriented pyrolytic graphite","authors":"M.A. Guazzelli , L.H. Avanzi , V.A.P. Aguiar , A.C. Vilas-Bôas , S.G. Alberton , S.H. Masunaga , E.F. Chinaglia , K. Araki , M. Nakamura , M.M. Toyama , F.F. Ferreira , M.T. Escote , R.B.B. Santos , N.H. Medina , J.R.B. Oliveira , F. Cappuzzello , M. Cavallaro , for the NUMEN collaboration","doi":"10.1016/j.diamond.2024.111803","DOIUrl":"10.1016/j.diamond.2024.111803","url":null,"abstract":"<div><div>Highly Ordered Pyrolytic Graphite (HOPG) has been extensively researched due to its chemical and physical properties that make it suitable for applications in several technologies. Its high thermal conductivity makes HOPG an excellent heat sink, a crucial characteristic for manufacturing targets used in nuclear reactions, such as those proposed by the NUMEN project. However, when subjected to different radiation sources, this material undergoes changes in its crystalline structure, which alters its intended functionality. This study examined HOPG sheets before and after exposure to a 14 MeV neutron beam. Morphological and crystallographic analyses reveal that even minor disruptions in the high atomic ordering result in modifications to its thermal properties. The results of this study are essential to establish the survival time of the HOPG used as thermal interface material to improve heat dissipation of a nuclear target to be bombarded by an intense high-energy heavy-ion beam.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111803"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702888","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}
Pub Date : 2024-11-19DOI: 10.1016/j.diamond.2024.111804
Yicheng Jiang , Jinshuo Pang , Xiang Zhang , Dongdong Zhao , Naiqin Zhao , Chunnian He , Enzuo Liu
Three-dimensional continuous graphene-reinforced copper matrix composites (3D-Gr/Cu) have excellent mechanical properties due to their special configuration and strengthening mechanisms. To figure out the deformation mechanism of 3D-Gr/Cu, atomic models of 3D-Gr/Cu with different configuration of graphene network (GN) and concentration of defects are constructed and studied by molecular dynamic simulations in this work. Atomic structure evolution during stretching process is investigated, and the mechanical properties of 3D-Gr/Cu, GN and Cu models are studied. Thereby, synergistic deformation between GN and Cu in 3D-Gr/Cu is revealed, and the deformation coordination between GN and Cu is regulated by GN structure and Gr/Cu interface. Furthermore, intrinsic defects in graphene with a suitable concentration help to construct the three-dimensional GN, improve the Gr/Cu interface bonding, and thus enhance the deformation coordination between GN and Cu. These results provide a profound explanation of the deformation mechanism and a new basis for defect engineering in 3D-Gr/Cu.
三维连续石墨烯增强铜基复合材料（3D-Gr/Cu）因其特殊的构型和增强机制而具有优异的力学性能。为了弄清三维石墨烯增强铜基复合材料的变形机理，本文构建了具有不同石墨烯网络（GN）构型和缺陷浓度的三维石墨烯增强铜基复合材料原子模型，并通过分子动力学模拟对其进行了研究。研究了拉伸过程中原子结构的演变，并对 3D-Gr/Cu、GN 和 Cu 模型的力学性能进行了研究。由此揭示了三维-Gr/Cu 中 GN 和 Cu 之间的协同变形，GN 和 Cu 之间的变形协调受 GN 结构和 Gr/Cu 界面的调节。此外，石墨烯中适当浓度的本征缺陷有助于构建三维石墨烯，改善石墨烯与铜界面的结合，从而增强石墨烯与铜之间的形变协调。这些结果为三维石墨烯和铜的形变机制提供了深刻的解释，也为三维石墨烯和铜的缺陷工程提供了新的基础。
{"title":"Unveiling the synergistic deformation mechanism in three-dimensional continuous network graphene-reinforced copper matrix composites","authors":"Yicheng Jiang , Jinshuo Pang , Xiang Zhang , Dongdong Zhao , Naiqin Zhao , Chunnian He , Enzuo Liu","doi":"10.1016/j.diamond.2024.111804","DOIUrl":"10.1016/j.diamond.2024.111804","url":null,"abstract":"<div><div>Three-dimensional continuous graphene-reinforced copper matrix composites (3D-Gr/Cu) have excellent mechanical properties due to their special configuration and strengthening mechanisms. To figure out the deformation mechanism of 3D-Gr/Cu, atomic models of 3D-Gr/Cu with different configuration of graphene network (GN) and concentration of defects are constructed and studied by molecular dynamic simulations in this work. Atomic structure evolution during stretching process is investigated, and the mechanical properties of 3D-Gr/Cu, GN and Cu models are studied. Thereby, synergistic deformation between GN and Cu in 3D-Gr/Cu is revealed, and the deformation coordination between GN and Cu is regulated by GN structure and Gr/Cu interface. Furthermore, intrinsic defects in graphene with a suitable concentration help to construct the three-dimensional GN, improve the Gr/Cu interface bonding, and thus enhance the deformation coordination between GN and Cu. These results provide a profound explanation of the deformation mechanism and a new basis for defect engineering in 3D-Gr/Cu.</div></div>","PeriodicalId":11266,"journal":{"name":"Diamond and Related Materials","volume":"151 ","pages":"Article 111804"},"PeriodicalIF":4.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702897","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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