Pub Date : 2024-10-18DOI: 10.1016/j.carbon.2024.119716
Yong Kim, Sungjun Kim, YongMin Kim, HyunJoon Yang, Woong-Ryeol Yu
Researchers have been working on creating fibers from single-walled carbon nanotubes (SWCNTs) that have optimal properties at the molecular level. However, the prepared SWCNT fibers have showed much lower properties than the ones predicted by theory because the interactions between SWCNTs and SWCNT bundles were not strong enough due to the poor alignment of SWCNTs in the fibers. In this study we improved the mechanical and electrical properties of the SWCNT fibers by using an electric field during the wet spinning process. The electric field, which was applied to the top of the syringe plunger and the tip of the spinneret, oriented the SWCNTs in the chlorosulfonic acid dope solution in a nozzle system, and made them more compact. The SWCNT fibers produced through our process exhibited a significant improvement in their properties. Specifically, we observed a 117.5 % increase in tensile strength and a 140.5 % increase in electrical conductivity. Importantly, these enhancements were achieved without the need for any additional post-treatments. This clearly demonstrates the effectiveness of our current wet spinning method.
{"title":"Enhanced mechanical and electrical properties of single-walled carbon nanotube fibers via electric field-assisted wet spinning","authors":"Yong Kim, Sungjun Kim, YongMin Kim, HyunJoon Yang, Woong-Ryeol Yu","doi":"10.1016/j.carbon.2024.119716","DOIUrl":"10.1016/j.carbon.2024.119716","url":null,"abstract":"<div><div>Researchers have been working on creating fibers from single-walled carbon nanotubes (SWCNTs) that have optimal properties at the molecular level. However, the prepared SWCNT fibers have showed much lower properties than the ones predicted by theory because the interactions between SWCNTs and SWCNT bundles were not strong enough due to the poor alignment of SWCNTs in the fibers. In this study we improved the mechanical and electrical properties of the SWCNT fibers by using an electric field during the wet spinning process. The electric field, which was applied to the top of the syringe plunger and the tip of the spinneret, oriented the SWCNTs in the chlorosulfonic acid dope solution in a nozzle system, and made them more compact. The SWCNT fibers produced through our process exhibited a significant improvement in their properties. Specifically, we observed a 117.5 % increase in tensile strength and a 140.5 % increase in electrical conductivity. Importantly, these enhancements were achieved without the need for any additional post-treatments. This clearly demonstrates the effectiveness of our current wet spinning method.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119716"},"PeriodicalIF":10.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533069","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 : 2024-10-18DOI: 10.1016/j.carbon.2024.119678
Jun Weng, Yanan Liu, Xiaoxiao Huang
Metal-Organic framework (MOF) derivatives have been applied as electromagnetic wave absorption (EMA) materials in recent years. Carbon nanotubes (CNTs) can achieve in situ growth on the surface of MOF derivatives. However, there is limited research on the EMA performance by regulating the morphology of the in situ grown CNTs. In this work, we prepared MOF-derived Ni@carbon nanotubes (Ni@CNT) with controllable length of CNTs by solvothermal and simple one-step pyrolysis method and revealed the CNT growth mechanism. We further investigated the effect of in situ grown CNT morphology on electromagnetic parameters and EMA performance. In situ grown CNTs of similar length on the surface of MOF derivatives lead to similar electromagnetic parameters. When the length of CNTs is short, the relaxation strength () is high, leading to excellent microwave absorption performance. For Ni@CNT-600, the reflection loss of −44.4 dB can be achieved at merely 1.72 mm. Finite element (FE) simulation was used to evaluate the EMA mechanism of different samples by calculating electric field and polarization strength. This work has explored the electromagnetic wave absorption performance from the perspective of microstructural tailoring, helpful for understanding the unique role of the in situ grown CNTs on the surface of MOF derivatives and investigating the ultra-thin electromagnetic wave absorption materials.
近年来，金属有机框架（MOF）衍生物已被用作电磁波吸收（EMA）材料。碳纳米管（CNT）可以在 MOF 衍生物表面实现原位生长。然而，通过调节原位生长的 CNT 的形态来提高 EMA 性能的研究还很有限。在这项工作中，我们采用溶解热法和简单的一步热解法制备了长度可控的 MOF 衍生物镍@碳纳米管（Ni@CNT），并揭示了 CNT 的生长机理。我们进一步研究了原位生长的 CNT 形貌对电磁参数和 EMA 性能的影响。在 MOF 衍生物表面原位生长的长度相近的 CNT 具有相似的电磁参数。当 CNT 的长度较短时，弛豫强度（Δε=εs-ε∞）较高，从而获得优异的微波吸收性能。对于 Ni@CNT-600，仅 1.72 mm 的反射损耗就可达到 -44.4 dB。通过计算电场和极化强度，有限元（FE）模拟评估了不同样品的 EMA 机制。该研究从微结构裁剪的角度探讨了电磁波吸收性能，有助于理解原位生长的 CNT 在 MOF 衍生物表面的独特作用，有助于研究超薄电磁波吸收材料。
{"title":"Synthesis of in situ grown CNTs on MOF-derived Ni@CNT with tailorable microstructures toward regulation of electromagnetic wave absorption performance","authors":"Jun Weng, Yanan Liu, Xiaoxiao Huang","doi":"10.1016/j.carbon.2024.119678","DOIUrl":"10.1016/j.carbon.2024.119678","url":null,"abstract":"<div><div>Metal-Organic framework (MOF) derivatives have been applied as electromagnetic wave absorption (EMA) materials in recent years. Carbon nanotubes (CNTs) can achieve in situ growth on the surface of MOF derivatives. However, there is limited research on the EMA performance by regulating the morphology of the in situ grown CNTs. In this work, we prepared MOF-derived Ni@carbon nanotubes (Ni@CNT) with controllable length of CNTs by solvothermal and simple one-step pyrolysis method and revealed the CNT growth mechanism. We further investigated the effect of in situ grown CNT morphology on electromagnetic parameters and EMA performance. In situ grown CNTs of similar length on the surface of MOF derivatives lead to similar electromagnetic parameters. When the length of CNTs is short, the relaxation strength (<span><math><mrow><mo>Δ</mo><mi>ε</mi><mo>=</mo><msub><mi>ε</mi><mi>s</mi></msub><mo>−</mo><msub><mi>ε</mi><mi>∞</mi></msub></mrow></math></span>) is high, leading to excellent microwave absorption performance. For Ni@CNT-600, the reflection loss of −44.4 dB can be achieved at merely 1.72 mm. Finite element (FE) simulation was used to evaluate the EMA mechanism of different samples by calculating electric field and polarization strength. This work has explored the electromagnetic wave absorption performance from the perspective of microstructural tailoring, helpful for understanding the unique role of the in situ grown CNTs on the surface of MOF derivatives and investigating the ultra-thin electromagnetic wave absorption materials.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119678"},"PeriodicalIF":10.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533056","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 : 2024-10-18DOI: 10.1016/j.carbon.2024.119724
Xiuwen Wang , Zhaohui Lu , Yuying Cao , Tingting Su , Lan Yu , Jie Sun , Bing Zhao , Chunmei Lv , Ying Xie
Construction of efficient non-precious catalyst with desired chemical composition and well-defined nanostructure is of great essential to enhance the kinetics of hydrogen evolution reaction (HER) and triiodide (I3−) reduction reaction (IRR), which is conducive to promote the development of green hydrogen production and obtain impressive photovoltaic performance of dye-sensitized solar cells (DSSCs). Herein, ZIF-8 derived N-doped carbon (NC) wrapped with two-dimensional Ni-doped MoS2 nanosheets (Ni–MoS2@NC) are elaborately designed. The catalytic activity of Ni–MoS2@NC for HER and IRR are significantly improved by modifying electronic structure through heteroatom doping. The optimized Ni–MoS2@NC has lower overpotential of 122 mV at 10 mA cm−2 in comparison with counterpart. Meanwhile, the power conversion efficiency (PCE) of DSSCs based on Ni–MoS2@NC CE catalyst is comparable to that of Pt. Density functional theory (DFT) calculation is used to unveil the mechanism of Ni–MoS2@NC for alkaline HER and IRR, namely, the multi-synergy of various sites endows Ni–MoS2@NC with appropriate Gibbs free energy for H∗ adsorption and water dissociation energy, while the top and interfacial S sites of Ni–MoS2@NC are responsible for the adsorption and activation of I3−. Our work provides a feasible route to design efficient catalysts in the field of energy conversion and understand mechanism.
构建具有所需化学成分和明确纳米结构的高效非贵金属催化剂对于提高氢进化反应（HER）和三碘化物（I3-）还原反应（IRR）的动力学至关重要，这有利于促进绿色制氢的发展，并使染料敏化太阳能电池（DSSC）获得令人瞩目的光电性能。本文精心设计了由 ZIF-8 衍生的掺杂 N 的碳（NC）包裹二维掺杂 Ni- 的 MoS2 纳米片（Ni-MoS2@NC）。通过掺杂杂原子改变电子结构，Ni-MoS2@NC 对 HER 和 IRR 的催化活性得到显著提高。与同类催化剂相比，优化后的 Ni-MoS2@NC 在 10 mA cm-2 时的过电位更低，仅为 122 mV。同时，基于 Ni-MoS2@NC CE 催化剂的 DSSC 的功率转换效率（PCE）与铂相当。密度泛函理论（DFT）计算揭示了 Ni-MoS2@NC 在碱性 HER 和 IRR 中的作用机理，即不同位点的多重协同作用赋予了 Ni-MoS2@NC 适当的 H∗ 吸附吉布斯自由能和水解离能，而 Ni-MoS2@NC 的顶部和界面 S 位点则负责 I3- 的吸附和活化。我们的工作为设计能量转换领域的高效催化剂和了解其机理提供了一条可行的途径。
{"title":"Multi-synergy enabling Ni-doped MoS2@N-doped carbon composite as versatile catalysts toward hydrogen production and photovoltaics","authors":"Xiuwen Wang , Zhaohui Lu , Yuying Cao , Tingting Su , Lan Yu , Jie Sun , Bing Zhao , Chunmei Lv , Ying Xie","doi":"10.1016/j.carbon.2024.119724","DOIUrl":"10.1016/j.carbon.2024.119724","url":null,"abstract":"<div><div>Construction of efficient non-precious catalyst with desired chemical composition and well-defined nanostructure is of great essential to enhance the kinetics of hydrogen evolution reaction (HER) and triiodide (I<sub>3</sub><sup>−</sup>) reduction reaction (IRR), which is conducive to promote the development of green hydrogen production and obtain impressive photovoltaic performance of dye-sensitized solar cells (DSSCs). Herein, ZIF-8 derived N-doped carbon (NC) wrapped with two-dimensional Ni-doped MoS<sub>2</sub> nanosheets (Ni–MoS<sub>2</sub>@NC) are elaborately designed. The catalytic activity of Ni–MoS<sub>2</sub>@NC for HER and IRR are significantly improved by modifying electronic structure through heteroatom doping. The optimized Ni–MoS<sub>2</sub>@NC has lower overpotential of 122 mV at 10 mA cm<sup>−2</sup> in comparison with counterpart. Meanwhile, the power conversion efficiency (PCE) of DSSCs based on Ni–MoS<sub>2</sub>@NC CE catalyst is comparable to that of Pt. Density functional theory (DFT) calculation is used to unveil the mechanism of Ni–MoS<sub>2</sub>@NC for alkaline HER and IRR, namely, the multi-synergy of various sites endows Ni–MoS<sub>2</sub>@NC with appropriate Gibbs free energy for H∗ adsorption and water dissociation energy, while the top and interfacial S sites of Ni–MoS<sub>2</sub>@NC are responsible for the adsorption and activation of I<sub>3</sub><sup>−</sup>. Our work provides a feasible route to design efficient catalysts in the field of energy conversion and understand mechanism.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119724"},"PeriodicalIF":10.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533054","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 aimed to investigate the impact of surface-modified layer (SML) on the bending deformation of van der Waals (vdW)-stacked materials. Bending tests were conducted on micrographite (highly oriented pyrolytic graphite, HOPG) cantilevers with controlled SML thickness using various ion beam irradiation conditions. Irradiation of the HOPG surface with ion beams at accelerating voltages of 30, 5 and 0.1 kV resulted in the formation of SMLs with thicknesses of approximately 10, 5 and less than 3 nm, respectively. Microcantilever-beam specimens with SML thicknesses of less than 3 nm and approximately 5 nm exhibited shear deformation with localized interlayer slip. In contrast, specimens with a thickness of approximately 10 nm showed no interlayer slip, with bending deformation dominating. This transition was attributed to the increase in SML thickness. The nominal shear modulus increased by a factor of approximately 1.58 and 2.23 for specimens with SML thicknesses of approximately 5 and 10 nm, respectively, compared with those with thicknesses of less than 3 nm. The resistance to subsequent nonlinear deformation also increased with thicker SML. These results indicate that the presence of SMLs of only a few nanometers to 10 nm suppressed interlayer slip and significantly enhanced the deformation resistance of micro-HOPGs.
{"title":"Nano-thick surface-modified layer governs bending deformation of micrographite","authors":"Wataru Matsunaga, Kiyohiko Kajiyama, Hiroyuki Hirakata","doi":"10.1016/j.carbon.2024.119712","DOIUrl":"10.1016/j.carbon.2024.119712","url":null,"abstract":"<div><div>This study aimed to investigate the impact of surface-modified layer (SML) on the bending deformation of van der Waals (vdW)-stacked materials. Bending tests were conducted on micrographite (highly oriented pyrolytic graphite, HOPG) cantilevers with controlled SML thickness using various ion beam irradiation conditions. Irradiation of the HOPG surface with ion beams at accelerating voltages of 30, 5 and 0.1 kV resulted in the formation of SMLs with thicknesses of approximately 10, 5 and less than 3 nm, respectively. Microcantilever-beam specimens with SML thicknesses of less than 3 nm and approximately 5 nm exhibited shear deformation with localized interlayer slip. In contrast, specimens with a thickness of approximately 10 nm showed no interlayer slip, with bending deformation dominating. This transition was attributed to the increase in SML thickness. The nominal shear modulus increased by a factor of approximately 1.58 and 2.23 for specimens with SML thicknesses of approximately 5 and 10 nm, respectively, compared with those with thicknesses of less than 3 nm. The resistance to subsequent nonlinear deformation also increased with thicker SML. These results indicate that the presence of SMLs of only a few nanometers to 10 nm suppressed interlayer slip and significantly enhanced the deformation resistance of micro-HOPGs.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119712"},"PeriodicalIF":10.5,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-17DOI: 10.1016/j.carbon.2024.119714
Zhiqiang Liu, Nan Lin, Yupeng Wu, Jiecai Li, Debo Liu, Yue Wang, Haibo Lin
Lead-carbon batteries (LCBs), an advanced form of lead-acid battery (LAB) technology, incorporate super-capacitive carbon materials into the negative electrode. Rice husk-based activated carbon (RHAC) is a promising additive for LCBs due to its favorable properties. However, RHAC's amorphous structure impedes electronic conduction, and its zigzag microporous channels hinder ion transport, leading to degraded high-rate performance. This study addresses these issues by growing carbon nanotubes (CNTs) in situ on RHAC through a one-step heat treatment, resulting in carbon nanotubes-loaded RHAC (CNTs/RHAC), and the electronic conductivity and ionic conductivity are simultaneously enhanced. When CNTs constitute 30 wt% of CNTs/RHAC, the negative electrode achieves a cycle life of 4721 cycles at a 2C rate under 50 % state of charge, which is 10.04 times that of the blank anode. The enhanced performance is attributed to the synergistic effects of CNTs and RHAC, where CNTs form long-range conductive networks among the negative electrode active material (NAM) and facilitate the diffusion and electro-deposition of Pb2+, while the high specific surface area (SSA) and hierarchical porous structure of RHAC enhance its capacitive function, leading to a stable lead-carbon composite structure.
{"title":"Rice husk-based activated carbon/carbon nanotubes composites for synergistically enhancing the performance of lead-carbon batteries","authors":"Zhiqiang Liu, Nan Lin, Yupeng Wu, Jiecai Li, Debo Liu, Yue Wang, Haibo Lin","doi":"10.1016/j.carbon.2024.119714","DOIUrl":"10.1016/j.carbon.2024.119714","url":null,"abstract":"<div><div>Lead-carbon batteries (LCBs), an advanced form of lead-acid battery (LAB) technology, incorporate super-capacitive carbon materials into the negative electrode. Rice husk-based activated carbon (RHAC) is a promising additive for LCBs due to its favorable properties. However, RHAC's amorphous structure impedes electronic conduction, and its zigzag microporous channels hinder ion transport, leading to degraded high-rate performance. This study addresses these issues by growing carbon nanotubes (CNTs) in situ on RHAC through a one-step heat treatment, resulting in carbon nanotubes-loaded RHAC (CNTs/RHAC), and the electronic conductivity and ionic conductivity are simultaneously enhanced. When CNTs constitute 30 wt% of CNTs/RHAC, the negative electrode achieves a cycle life of 4721 cycles at a 2C rate under 50 % state of charge, which is 10.04 times that of the blank anode. The enhanced performance is attributed to the synergistic effects of CNTs and RHAC, where CNTs form long-range conductive networks among the negative electrode active material (NAM) and facilitate the diffusion and electro-deposition of Pb<sup>2+</sup>, while the high specific surface area (SSA) and hierarchical porous structure of RHAC enhance its capacitive function, leading to a stable lead-carbon composite structure.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119714"},"PeriodicalIF":10.5,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533060","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 : 2024-10-16DOI: 10.1016/j.carbon.2024.119697
Da-Jiang Liu , Jie Zhang , Long Qi , James W. Evans
Machine learning (ML)-based molecular dynamics (MD) simulations of the formation of a class of N-doped nanoporous carbons are performed to assess their disordered partially graphitized nanoscale structure. The study is motivated by the effectiveness of so-called nitrogen assembly carbons (NACs) for catalysis applications. Benchmark simulations for pure-C disordered graphitic systems reveal the importance of reliably capturing the vdW component of the potentials in order to accurately describe the tendency for layering of disordered graphene-like sheets. In our modeling, this is achieved by a transfer learning strategy incorporating features of the energetics from the optB88-vdW DFT functional into potentials initially trained with a less expensive functional, thereby providing a superior description of the pure-C systems. Generation from MD simulations of realistic partially graphitized structures is significantly more challenging for N-doped versus for pure C systems. However, such structures are achieved by a tailored MD simulation protocol mimicking the experimental synthesis process and in particular incorporating an annealing and subsequent quenching stages. Simulated PXRD patterns effectively reproduce the features of experimental observations for NACs, including the appearance of a prominent but broad (002) peak at around 25, and the development of another weaker feature associated with in-layer ordering of mixed C-N graphene-like sheets.
对一类掺氮纳米多孔碳的形成进行了基于机器学习（ML）的分子动力学（MD）模拟，以评估其无序的部分石墨化纳米级结构。这项研究的动机是所谓的氮组装碳（NAC）在催化应用中的有效性。对纯碳无序石墨系统的基准模拟表明，为了准确描述无序石墨烯类薄片的分层趋势，可靠地捕捉电势的 vdW 分量非常重要。在我们的建模中，通过迁移学习策略将 optB88-vdW DFT 函数的能量特征纳入最初用成本较低的函数训练的电位中，从而实现了对纯 C 系统的卓越描述。通过 MD 模拟生成逼真的部分石墨化结构对于掺杂 N 的系统来说比纯 C 系统更具挑战性。不过，通过模仿实验合成过程，特别是结合退火和随后的淬火阶段的定制 MD 模拟协议，这种结构是可以实现的。模拟的 PXRD 图样有效地再现了 NAC 的实验观察特征，包括在 25∘ 左右出现一个突出但宽阔的 (002) 峰，以及与层内混合 C-N 类石墨烯片有序相关的另一个较弱特征。
{"title":"Molecular simulation using transfer-learned potentials for the disordered nanoscale structure of nitrogen-doped nanoporous carbons","authors":"Da-Jiang Liu , Jie Zhang , Long Qi , James W. Evans","doi":"10.1016/j.carbon.2024.119697","DOIUrl":"10.1016/j.carbon.2024.119697","url":null,"abstract":"<div><div>Machine learning (ML)-based molecular dynamics (MD) simulations of the formation of a class of N-doped nanoporous carbons are performed to assess their disordered partially graphitized nanoscale structure. The study is motivated by the effectiveness of so-called nitrogen assembly carbons (NACs) for catalysis applications. Benchmark simulations for pure-C disordered graphitic systems reveal the importance of reliably capturing the vdW component of the potentials in order to accurately describe the tendency for layering of disordered graphene-like sheets. In our modeling, this is achieved by a transfer learning strategy incorporating features of the energetics from the optB88-vdW DFT functional into potentials initially trained with a less expensive functional, thereby providing a superior description of the pure-C systems. Generation from MD simulations of realistic partially graphitized structures is significantly more challenging for N-doped versus for pure C systems. However, such structures are achieved by a tailored MD simulation protocol mimicking the experimental synthesis process and in particular incorporating an annealing and subsequent quenching stages. Simulated PXRD patterns effectively reproduce the features of experimental observations for NACs, including the appearance of a prominent but broad (002) peak at around 25<span><math><msup><mrow></mrow><mrow><mo>∘</mo></mrow></msup></math></span>, and the development of another weaker feature associated with in-layer ordering of mixed C-N graphene-like sheets.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119697"},"PeriodicalIF":10.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533053","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 : 2024-10-16DOI: 10.1016/j.carbon.2024.119713
Jing Zhang , Yang Wang , Qian Chen , Yixin Su , Shandan Bai , Yusuke Ootani , Nobuki Ozawa , Koshi Adachi , Momoji Kubo
Diamond-like carbon (DLC) is widely utilized in various fields as a promising solid lubricating material. However, the lubricity and wear behaviors of DLC are highly sensitive to the environment, and the relevant mechanisms are hidden by complex tribochemical reactions at the friction interface. In this study, we performed reactive molecular dynamics (RMD) simulations of DLC to clarify the wear mechanisms in various environments (vacuum, water, and oxygen environments). Two types of tribochemical reaction-induced wear were observed: chemical wear induced by the triboemission of CxHy and CxHyOz compounds and mechanical wear induced by the formation of interfacial C–C bonds. Moreover, the results revealed that the environment affects the tribological behavior of DLC primarily through its impact on the surface chemical state, that is, the quantity and type of surface terminations. In terms of the number of surface terminations, the more surface terminations there are, the more chemical wear and less mechanical wear they cause. In particular, oxygen-containing terminations (e.g., C–OH and C=O) are more resistant than H terminations to interfacial bond formation and mechanical wear. The present work provides important insights into the wear mechanisms of DLC, aiding in the reduction of DLC wear by controlling the environment.
{"title":"Environment-dependent tribochemical reaction and wear mechanisms of Diamond-like carbon: A reactive molecular dynamics study","authors":"Jing Zhang , Yang Wang , Qian Chen , Yixin Su , Shandan Bai , Yusuke Ootani , Nobuki Ozawa , Koshi Adachi , Momoji Kubo","doi":"10.1016/j.carbon.2024.119713","DOIUrl":"10.1016/j.carbon.2024.119713","url":null,"abstract":"<div><div>Diamond-like carbon (DLC) is widely utilized in various fields as a promising solid lubricating material. However, the lubricity and wear behaviors of DLC are highly sensitive to the environment, and the relevant mechanisms are hidden by complex tribochemical reactions at the friction interface. In this study, we performed reactive molecular dynamics (RMD) simulations of DLC to clarify the wear mechanisms in various environments (vacuum, water, and oxygen environments). Two types of tribochemical reaction-induced wear were observed: chemical wear induced by the triboemission of C<sub>x</sub>H<sub>y</sub> and C<sub>x</sub>H<sub>y</sub>O<sub>z</sub> compounds and mechanical wear induced by the formation of interfacial C–C bonds. Moreover, the results revealed that the environment affects the tribological behavior of DLC primarily through its impact on the surface chemical state, that is, the quantity and type of surface terminations. In terms of the number of surface terminations, the more surface terminations there are, the more chemical wear and less mechanical wear they cause. In particular, oxygen-containing terminations (e.g., C–OH and C=O) are more resistant than H terminations to interfacial bond formation and mechanical wear. The present work provides important insights into the wear mechanisms of DLC, aiding in the reduction of DLC wear by controlling the environment.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119713"},"PeriodicalIF":10.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-15DOI: 10.1016/j.carbon.2024.119710
Xinming Wang , Jing Zhong
Agglomerates of carbon nanotube (CNT) are typically considered as defects in cement matrix, yet without a clear physiochemical picture regarding why and how. By representing CNT agglomerates with CNT sponge powders (CNTSPPs), we discovered that hydrates can precipitate in the pores of CNTSPPs to form a CNT/hydrates nanocomposite shell, the thickness and compactness of which are dependent on the curing temperature. In contrast to the detrimental effects of CNTSPPs for the samples cured under standard condition, the addition of 0.05 wt % CNTSPPs increased the 28d compressive strength by ∼16 % compared to the reference sample under steam curing condition. This is because steam curing condition significantly improves the hydrophilicity of CNTSPPs, resulting in its absorption of pore solution and calcium ions, which eventually increase the CNT/hydrates nanocomposites shell thickness and microhardness. Such nanocomposites shell with high mechanical properties can screen the negative effects of the porous inner CNTSPPs.
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The intriguing fluorescence characteristics of carbon dots (CDs) have led to many sensor applications, particularly for dopamine (DA), a molecule linked to various diseases. This study prepares CDs from glucose and glucosamine (nitrogen-free and nitrogen-containing precursors) using a simple solution plasma process (SPP). We explore how nitrogen elements and counterions in glucosamine (hydrochloride and sulfate) affect CD properties and their ability to modulate fluorescence for DA detection. Glucosamine offers three advantages over glucose: (i) single-step CD synthesis via SPP, (ii) enhanced fluorescence of CDs, and (iii) improved fluorescence response to DA. We investigate the DA detection capabilities of N,S-CDs (from glucosamine sulfate) and N,Cl-CDs (from glucosamine hydrochloride). Both can sense DA with distinct photoluminescence responses. N,S-CDs show selectivity and fluorescence brightening upon DA interaction, with a detection limit of 33.05 μM. N,Cl-CDs demonstrate higher sensitivity with a lower detection limit of 0.1212 μM through fluorescence quenching. Silver ions (Ag+) may also contribute to N,Cl-CDs quenching; however, the observed color change to gray due to silver nanoparticle (AgNP) formation helps pinpoint the quenching substance. The varied photoluminescence responses arise from different surface functional groups: N,S-CDs have amino-rich surfaces, while N,Cl-CDs have conjugated carbonyl-rich surfaces. This study illustrates the mechanisms of DA detection and AgNP formation, suggesting the potential of CDs in medical diagnostics as selective tools for disease diagnosis. Additionally, we compare the DA sensing methodology of our CDs with existing literature, highlighting the advantages of our sensor.
碳点（CD）的荧光特性引人入胜，因此被广泛应用于传感器领域，尤其是多巴胺（DA）这种与多种疾病相关的分子。本研究采用简单的溶液等离子工艺 (SPP) 从葡萄糖和氨基葡萄糖（无氮和含氮前体）制备碳点。我们探讨了氨基葡萄糖（盐酸盐和硫酸盐）中的氮元素和反离子如何影响 CD 的特性及其调节荧光以检测 DA 的能力。与葡萄糖相比，葡萄糖胺具有三个优势：(i) 通过 SPP 单步合成 CD；(ii) 增强 CD 的荧光；(iii) 改善对 DA 的荧光响应。我们研究了 N,S-CD（来自氨基葡萄糖硫酸盐）和 N,Cl-CD（来自氨基葡萄糖盐酸盐）的 DA 检测能力。二者都能通过不同的光致发光反应来感知 DA。N,S-CDs在与 DA 相互作用时显示出选择性和荧光增亮，检测限为 33.05 μM。通过荧光淬灭，N,Cl-CDs 表现出更高的灵敏度，检测限低至 0.1212 μM。银离子（Ag+）也可能导致 N,Cl-CDs淬灭；不过，观察到的银纳米粒子（AgNP）形成导致的颜色变灰有助于确定淬灭物质。不同的光致发光反应源于不同的表面官能团：N,S-CDs表面富含氨基，而N,Cl-CDs表面富含共轭羰基。这项研究阐述了 DA 检测和 AgNP 形成的机制，表明 CDs 作为疾病诊断的选择性工具在医学诊断中的潜力。此外，我们还将我们的 CD 的 DA 传感方法与现有文献进行了比较，突出了我们的传感器的优势。
{"title":"Solution plasma synthesis of nitrogen-doped carbon dots from glucosamines: Comparative fluorescence modulation for dopamine detection","authors":"Sasimaporn Treepet , Thipthunya Duangmanee , Chayanaphat Chokradjaroen , Kyusung Kim , Nagahiro Saito , Anyarat Watthanaphanit","doi":"10.1016/j.carbon.2024.119705","DOIUrl":"10.1016/j.carbon.2024.119705","url":null,"abstract":"<div><div>The intriguing fluorescence characteristics of carbon dots (CDs) have led to many sensor applications, particularly for dopamine (DA), a molecule linked to various diseases. This study prepares CDs from glucose and glucosamine (nitrogen-free and nitrogen-containing precursors) using a simple solution plasma process (SPP). We explore how nitrogen elements and counterions in glucosamine (hydrochloride and sulfate) affect CD properties and their ability to modulate fluorescence for DA detection. Glucosamine offers three advantages over glucose: (<em>i</em>) single-step CD synthesis via SPP, (<em>ii</em>) enhanced fluorescence of CDs, and (<em>iii</em>) improved fluorescence response to DA. We investigate the DA detection capabilities of N,S-CDs (from glucosamine sulfate) and N,Cl-CDs (from glucosamine hydrochloride). Both can sense DA with distinct photoluminescence responses. N,S-CDs show selectivity and fluorescence brightening upon DA interaction, with a detection limit of 33.05 μM. N,Cl-CDs demonstrate higher sensitivity with a lower detection limit of 0.1212 μM through fluorescence quenching. Silver ions (Ag<sup>+</sup>) may also contribute to N,Cl-CDs quenching; however, the observed color change to gray due to silver nanoparticle (AgNP) formation helps pinpoint the quenching substance. The varied photoluminescence responses arise from different surface functional groups: N,S-CDs have amino-rich surfaces, while N,Cl-CDs have conjugated carbonyl-rich surfaces. This study illustrates the mechanisms of DA detection and AgNP formation, suggesting the potential of CDs in medical diagnostics as selective tools for disease diagnosis. Additionally, we compare the DA sensing methodology of our CDs with existing literature, highlighting the advantages of our sensor.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"231 ","pages":"Article 119705"},"PeriodicalIF":10.5,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533046","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 : 2024-10-13DOI: 10.1016/j.carbon.2024.119704
Marjan Monshi , Maziar Moussavi , Domantas Peckus , Erika Rajackaitė , Andrius Vasiliauskas , Mindaugas Andrulevičius , Tomas Tamulevičius , Sigitas Tamulevičius
Graphite-encapsulated metal nanoparticles hold great potential across various applications due to their unique combination of metal and graphitic properties. While Raman spectroscopy is widely used to assess the graphitic shells, metrics derived from prominent Raman bands often prove unreliable when analyzing such structures with a large number of heterogeneous flakes and are mostly applicable to few-layer graphene. However, researchers continue to face challenges in identifying reliable metrics that accurately reflect two key properties of graphitic shells: thickness and degree of graphitization. In this study, graphitic shells were synthesized via plasma-enhanced chemical vapor deposition (PECVD) at low temperatures (500 °C), seeded by nickel nano-islands. A full-factorial experiment was designed to explore a diverse sample space by varying two key input factors: the initial thickness of the nickel seeding film and the duration of carbon deposition. Using resource-intensive surface characterization techniques (SEM, EDS, XPS, and AFM), we verified encapsulation efficiency and morphology, identifying strong correlations between the input factors and properties of the shells. To gain insights into structural characteristics, we employed conventional spectroscopy techniques (Raman, UV–Vis-nIR transmission, and Transient Absorption Spectroscopy), introducing 107 metrics derived from spectral data. Principal Component Analysis (PCA) aligned the input factors, and their corresponding shell properties, with the first two principal components. Accordingly, we identified the most relevant metrics including new candidates derived from less prominent Raman bands. Additionally, inter-metric correlations enable interchangeable use of spectroscopy techniques. This study marks the first multi-spectroscopic correlation analysis of graphitic shells and provides a novel framework for evaluating their properties.
{"title":"Correlation study of graphitic shell encapsulated nickel: A multi-spectroscopic approach","authors":"Marjan Monshi , Maziar Moussavi , Domantas Peckus , Erika Rajackaitė , Andrius Vasiliauskas , Mindaugas Andrulevičius , Tomas Tamulevičius , Sigitas Tamulevičius","doi":"10.1016/j.carbon.2024.119704","DOIUrl":"10.1016/j.carbon.2024.119704","url":null,"abstract":"<div><div>Graphite-encapsulated metal nanoparticles hold great potential across various applications due to their unique combination of metal and graphitic properties. While Raman spectroscopy is widely used to assess the graphitic shells, metrics derived from prominent Raman bands often prove unreliable when analyzing such structures with a large number of heterogeneous flakes and are mostly applicable to few-layer graphene. However, researchers continue to face challenges in identifying reliable metrics that accurately reflect two key properties of graphitic shells: thickness and degree of graphitization. In this study, graphitic shells were synthesized via plasma-enhanced chemical vapor deposition (PECVD) at low temperatures (500 °C), seeded by nickel nano-islands. A full-factorial experiment was designed to explore a diverse sample space by varying two key input factors: the initial thickness of the nickel seeding film and the duration of carbon deposition. Using resource-intensive surface characterization techniques (SEM, EDS, XPS, and AFM), we verified encapsulation efficiency and morphology, identifying strong correlations between the input factors and properties of the shells. To gain insights into structural characteristics, we employed conventional spectroscopy techniques (Raman, UV–Vis-nIR transmission, and Transient Absorption Spectroscopy), introducing 107 metrics derived from spectral data. Principal Component Analysis (PCA) aligned the input factors, and their corresponding shell properties, with the first two principal components. Accordingly, we identified the most relevant metrics including new candidates derived from less prominent Raman bands. Additionally, inter-metric correlations enable interchangeable use of spectroscopy techniques. This study marks the first multi-spectroscopic correlation analysis of graphitic shells and provides a novel framework for evaluating their properties.</div></div>","PeriodicalId":262,"journal":{"name":"Carbon","volume":"232 ","pages":"Article 119704"},"PeriodicalIF":10.5,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586668","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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