IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-08 DOI: 10.1016/j.carbon.2024.119811

Beom Won Seo , Guk Hyun Nam , Hyundo Yang , Sanghee Jung , Jongcheol Park , Il-Suk Kang , Deuk Young Kim , Hak Dong Cho , Jong-Kwon Lee

We report on the adjustable lensing effect and switchable mode performance of a graphene-based Infrared (IR) Fresnel zone plate (FZP) formed on a double-side polished Si substrate. The focusing characteristics of the graphene FZP in the IR wavelength range have been systematically investigated as a function of the Fermi energy (E_F) of the multilayer graphene rings and the thickness of the Si substrate using the Finite-Difference Time-Domain method. This graphene FZP lens enhances the focal intensity of incident light at wavelengths where the multiple internal reflections in the Si substrate is periodically maximized. Also, the contrast ratios of reflectance and transmittance between the regions with and without graphene rings, which affects the focusing performance, are effectively controlled through intraband transitions depending on the E_F of graphene FZP pattern. Specifically, the 8-layer graphene FZP lens transmits the incident light with a wavelength of 8 μm when the E_F of the graphene is lower than 0.2 eV, while it operates as both transmissive and reflective Fresnel lens when the E_F exceeds 0.2 eV. By directly depositing Ag nanoparticles on this graphene FZP to enable E_f control of graphene rings without the need for electrodes, we have experimentally confirmed the focusing performance and mode conversion properties.

我们报告了在双面抛光硅衬底上形成的基于石墨烯的红外线（IR）菲涅尔区板（FZP）的可调透镜效应和可切换模式性能。利用有限差分时域法，系统地研究了石墨烯 FZP 在红外波长范围内的聚焦特性与多层石墨烯环的费米能 (EF) 和硅衬底厚度的函数关系。这种石墨烯 FZP 透镜增强了入射光在波长处的焦距强度，在这些波长处，硅基板的多次内部反射周期性地达到最大。此外，有石墨烯环和无石墨烯环区域之间的反射率和透射率对比度会影响聚焦性能，而根据石墨烯 FZP 图案的 EF 值，可以通过带内转换有效控制反射率和透射率对比度。具体来说，当石墨烯的 EF 值低于 0.2 eV 时，8 层石墨烯 FZP 透镜可透射波长为 8 μm 的入射光；而当 EF 值超过 0.2 eV 时，该透镜既可作为透射型菲涅尔透镜，也可作为反射型菲涅尔透镜。通过在这种石墨烯 FZP 上直接沉积银纳米粒子，我们在无需电极的情况下实现了石墨烯环的 Ef 控制，并在实验中证实了其聚焦性能和模式转换特性。

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引用次数: 0

Dielectric synergistic gradient metamaterials enable exceptional ultra–wideband microwave absorption and antibacterial properties 介电协同梯度超材料可实现卓越的超宽带微波吸收和抗菌特性

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-08 DOI: 10.1016/j.carbon.2024.119813

Xin Yang , Bohong Li , Baoshun Lin , Hong Wang , Tong Zhu , Xiao Su , Yanyu Gao , Zhanglu Lei , Pingan Liu , Qianqian Yu , LinGe Wang

Interface structure design and multi–component strategies for regulating electromagnetic parameters to achieve efficient microwave absorption remain a challenge. In this study, a composite film with a heterogeneous structure, PAN@PPy@Ti₃C₂T_x@GO (PPTG) was fabricated through electrospinning, in situ oxidative polymerization, and dip–coating processes, achieving excellent electromagnetic wave absorption and antibacterial properties. When the filler content is only 20 wt%, the PPTG film exhibits an ultra–wide bandwidth, with a minimum reflection loss value (RLmin) of −49.98 dB (2.2 mm, 16.72 GHz), and the maximum effective absorption bandwidth (EAB) reaches 8.0 GHz (2.5 mm). The outstanding absorption performance is attributed to quarter–wavelength theory, polarization, multiple reflections and scattering, impedance matching, metamaterial properties, quasi–antenna effect, conductive loss, and magnetic loss. Excitingly, the radar cross–section (RCS) of the PPTG film can be reduced by up to 25.72 dB•m², indicating excellent radar stealth properties. Moreover, the PPTG film exhibits excellent antibacterial properties. This research, based on the MXene absorber, provides new insights into the development of lightweight, efficient, and antibacterial microwave–absorbing materials.

界面结构设计和调节电磁参数以实现高效微波吸收的多组分策略仍然是一项挑战。本研究通过电纺丝、原位氧化聚合和浸涂工艺制备了一种具有异质结构的复合薄膜--PAN@PPy@Ti3C2Tx@GO（PPTG），实现了优异的电磁波吸收和抗菌性能。当填料含量仅为 20 wt% 时，PPTG 薄膜具有超宽带宽，最小反射损耗值（RLmin）为 -49.98 dB（2.2 mm，16.72 GHz），最大有效吸收带宽（EAB）达到 8.0 GHz（2.5 mm）。出色的吸收性能归功于四分之一波长理论、极化、多重反射和散射、阻抗匹配、超材料特性、准天线效应、导电损耗和磁损耗。令人兴奋的是，PPTG 薄膜的雷达截面（RCS）可降低高达 25.72 dB-m2，显示出卓越的雷达隐身性能。此外，PPTG 薄膜还具有优异的抗菌性能。这项基于 MXene 吸收器的研究为开发轻质、高效、抗菌的微波吸收材料提供了新的思路。

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引用次数: 0

Replication of mechanochemical syntheses of γ-graphyne from calcium carbide fails to produce the claimed product 从碳化钙中复制机械化学合成γ-石墨烯的方法未能生产出声称的产品

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-08 DOI: 10.1016/j.carbon.2024.119808

Ezra R. Kone , Sarah Nasri , Grace L. Parker , Victor G. Desyatkin , William B. Martin , John F. Trant , Valentin O. Rodionov

Several recent articles by Cui and coworkers claim syntheses of γ-graphyne, a novel sp²/sp¹ allotrope of carbon, directly from calcium carbide. Here, we describe the replication of the key experiments from this series of articles. We did not observe the formation of γ-graphyne under the reported conditions. The characterization data from our replications are partially consistent with the results reported by Cui. However, we show that the claimed experiments produce only heavily contaminated, amorphous chars with no detectable sp¹ carbons.

崔永元及其同事最近发表了几篇文章，声称直接从碳化钙中合成了γ-石墨烯，一种新型的碳sp2/sp1同素异形体。在此，我们介绍了这一系列文章中关键实验的重复情况。在报告的条件下，我们没有观察到γ-石墨烯的形成。我们复制的表征数据与 Cui 报告的结果部分一致。不过，我们表明，所声称的实验只产生了严重污染的无定形炭，没有检测到 sp1 碳。

引用次数: 0

Highly stretchable and strain-insensitive multilayered electromagnetic interference shielding films prepared via a simple soaking-infiltration strategy 通过简单的浸泡-过滤策略制备出高度可拉伸且对应变不敏感的多层电磁干扰屏蔽膜

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-07 DOI: 10.1016/j.carbon.2024.119809

Ruilin Yin , Tingkang Yuan , Chengwei Li , Hao Zhang , Huan Chen , Ningxuan Wen , Xueqing Zuo , Chen Chen , Lujun Pan , Zeng Fan

Stretchable electromagnetic interference (EMI) shielding films are crucial for wearable electronics. However, it is challenging to further endow the EMI shielding films with good stretchability and satisfactory EMI shielding effectiveness (EMI SE) under large strains. Herein, we successfully prepared high-performance stretchable polydimethylsiloxane (PDMS)/single-walled carbon nanotube buckypaper (SWNT BP)/PDMS EMI shielding films with multi-graded conductive networks via a soaking-infiltration strategy. In this multilayered film, infiltration layers of SWNT/PDMS were particularly created between elastic PDMS and brittle SWNT BP. Owing to the multilayered structure and conductivity compensation effects arising from infiltration layers, our EMI shielding films exhibited excellent EMI SE of 34.2 dB with high stretchability of >400 %. The outstanding EMI SE could be well maintained under large strains. At <50 % strain, the relative change in EMI SE (|ΔSE/SE₀|) remained consistently below 10 %, while at even 100 % strain, |ΔSE/SE₀| was only ∼35 %. Furthermore, we proposed a parallel-series hybrid model to describe electrical conduction in straining films. Due to their excellent conductivity under strain, the films could also serve as stretchable Joule heaters. This work provides a novel and simple approach for constructing strain-insensitive conductive films, with potential applications in stretchable EMI shielding and thermal management.

可拉伸电磁干扰（EMI）屏蔽膜对于可穿戴电子设备至关重要。然而，如何进一步赋予电磁干扰屏蔽膜良好的拉伸性和在大应变下令人满意的电磁干扰屏蔽效果（EMI SE）是一项挑战。在此，我们通过浸泡-过滤策略，成功制备了具有多级导电网络的高性能可拉伸聚二甲基硅氧烷（PDMS）/单壁碳纳米管降压纸（SWNT BP）/PDMS EMI 屏蔽膜。在这种多层薄膜中，SWNT/PDMS 的浸润层特别建立在弹性 PDMS 和脆性 SWNT BP 之间。由于多层结构和浸润层产生的传导补偿效应，我们的 EMI 屏蔽膜表现出 34.2 dB 的优异 EMI SE，并具有 400 % 的高拉伸性。出色的 EMI SE 在较大的应变下也能很好地保持。在应变为 50 % 时，EMI SE 的相对变化（|ΔSE/SE0|）始终保持在 10 % 以下，而在应变为 100 % 时，|ΔSE/SE0| 也仅为∼35 %。此外，我们还提出了一种平行序列混合模型来描述应变薄膜中的电导。由于薄膜在应变下具有出色的导电性，因此也可用作可拉伸焦耳加热器。这项研究为构建应变敏感导电薄膜提供了一种新颖而简单的方法，有望应用于可拉伸电磁干扰屏蔽和热管理领域。

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引用次数: 0

The effects of CNT type, alignment and dopants on piezoresistance in CNT fibres CNT 类型、排列和掺杂剂对 CNT 纤维压阻的影响

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-07 DOI: 10.1016/j.carbon.2024.119810

Anastasiia Mikhalchan , Ángel Víctor Labordet Álvarez , Moisés Zarzoso , Carlos González , Juan J. Vilatela

Carbon nanotube fibres (CNTF) are piezoresistive, hence heralded as deformation sensors in applications ranging from flexible touch sensors to artificial skins and robotics. This work studies the piezoresistive behaviour of a wide range of CNT fibres from different sources, processing routes and microstructures. It provides a unifying view of the factors controlling piezoresistance in CNT fibres and related nanocarbon networks. We clarify the role of alignment and concentration of dopants and the constituent CNT type, demonstrating that the origin of piezoresistance in aligned fibres is the direct deformation of the constituent nanotubes, therefore, it is governed by the bulk modulus and thus the degree of CNT alignment. Doping through intercalation, which does not affect modulus or CNT separation, is detrimental to piezoresistive sensing, reducing the gauge factor proportionally to its decrease in resistivity. Aligned fibres show a quasi-linear piezoresistive response, with a positive change in resistance for all deformation modes applied: axial tension, axial or transverse compression. The axial gauge factor is shown to be proportional to fibre Young's modulus, with values of 2–9 for fibres spun from aerogels and above 30 for undoped fibres spun from liquid crystal solutions, respectively. Piezoresistance is attributed to the formation of internal barriers for conduction between metallic regions, which arise from the heterogeneous stress distribution along individual CNTs inherent in shear lag-type stress transfer. Commercial multifilament CNT yarns with a high degree of alignment and a format amenable for integration in large structures have demonstrated the piezoresistive gauge factors of 4 and sufficient sensitivity at strains below 1 % suitable for structural health monitoring of engineering structural composites.

碳纳米管纤维（CNTF）具有压阻特性，因此在柔性触摸传感器、人造皮肤和机器人等应用中被誉为形变传感器。这项工作研究了不同来源、不同加工工艺和不同微结构的各种 CNT 纤维的压阻行为。它为控制 CNT 纤维和相关纳米碳网络压阻的因素提供了一个统一的视角。我们阐明了掺杂剂的排列和浓度以及组成碳纳米管类型的作用，证明了排列纤维中压阻的起源是组成纳米管的直接变形，因此它受体积模量和碳纳米管排列程度的制约。通过插层掺杂不会影响模量或碳纳米管的分离，但却不利于压阻传感，因为电阻率的降低会成正比地降低量规因子。排列整齐的纤维显示出准线性压阻响应，在轴向拉伸、轴向或横向压缩等所有变形模式下，电阻都会发生正向变化。轴向量规因子与纤维的杨氏模量成正比，气凝胶纺制的纤维的量规因子值为 2-9，而液晶溶液纺制的未掺杂纤维的量规因子值超过 30。压阻是由于金属区域之间形成了传导的内部障碍，这种障碍产生于剪切滞后型应力传递所固有的沿单根 CNT 的异质应力分布。商用多丝 CNT 纱线具有高度的对准性和适合集成到大型结构中的形式，已证明其压阻计系数为 4，在应变低于 1 % 时具有足够的灵敏度，适合工程结构复合材料的结构健康监测。

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引用次数: 0

Nitrogen-doped modified graphene aerogel enhancing interfacial bonding with lithium aluminium silicate ceramics for broadband microwave absorption 掺氮改性石墨烯气凝胶增强与硅酸铝锂陶瓷的界面结合，用于宽带微波吸收

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-07 DOI: 10.1016/j.carbon.2024.119794

Jing'wen Qi , Jia'qi Zhang , Yu An , Tian'yu Zhang , Ran Wang , Wen'xuan Zhang , Yan'xin Zhang , Ya'nan Yang , Long Xia

The swift progression of e-communication technology has resulted in significant electromagnetic pollution, necessitating the urgent need for effective microwave-absorbing materials to mitigate this issue. Augmenting heterogeneous phase interfaces and incorporating heteroatoms constitute viable strategies for enhancing the electromagnetic properties of functional materials. In this study, a series of lithium aluminium silicate glass-ceramic/nitrogen-doped graphene (LAS/N-GF) aerogels was synthesised via the hydrothermal and freeze-drying methods. An innovative bonding mechanism for the heterogeneous phase interface was revealed, in which nitrogen doping enabled the formation of lattice defects in LAS ceramic particles and graphene and promoted a closed approach for unsaturated carbon and silicon atoms to form carbon-silicon bonds through the electrostatic force generated by interfacial polarization. Given that covalent bonds are widely recognized as stable carrier channels, the presence of carbon-silicon bonds at the interface facilitates electron migration, ultimately leading to improved microwave absorption. The maximum absorptivity of the LAS/N-GF aerogels could reach −47.98 dB at 8.96 GHz with a filler loading as low as 10 wt%. It is noteworthy that the LAS/N-GF aerogel exhibits an effective absorption bandwidth of 8.34 GHz, which fully spans the entire X-band and more than two-thirds of the Ku-band. Such exceptional performance is rarely observed in dielectric loss materials. Finally, the application potential of the LAS/N-GF aerogels in microwave absorbers was simulated and analysed. The unique chemical phenomenon stemming from the bonding at the carbon material-ceramic interface offers a fresh perspective in interface science, enabling a deeper comprehension of the underlying mechanism of microwave absorption.

电子通信技术的迅猛发展造成了严重的电磁污染，因此迫切需要有效的微波吸收材料来缓解这一问题。增强异质相界面和加入杂原子是提高功能材料电磁特性的可行策略。本研究通过水热法和冷冻干燥法合成了一系列硅酸铝锂玻璃陶瓷/掺氮石墨烯（LAS/N-GF）气凝胶。研究揭示了异质相界面的创新成键机制，其中氮掺杂使得锂硅酸盐陶瓷颗粒和石墨烯形成了晶格缺陷，并通过界面极化产生的静电力促进了不饱和碳原子和硅原子形成碳硅键的封闭方法。鉴于共价键被广泛认为是稳定的载流子通道，界面上碳硅键的存在有利于电子迁移，最终改善微波吸收。填料含量低至 10 wt%时，LAS/N-GF 气凝胶在 8.96 GHz 频率下的最大吸收率可达 -47.98 dB。值得注意的是，LAS/N-GF 气凝胶的有效吸收带宽为 8.34 GHz，完全跨越了整个 X 波段和超过三分之二的 Ku 波段。这种优异的性能在介质损耗材料中很少见。最后，对 LAS/N-GF 气凝胶在微波吸收器中的应用潜力进行了模拟和分析。碳材料-陶瓷界面键合产生的独特化学现象为界面科学提供了一个全新的视角，使人们能够更深入地理解微波吸收的内在机制。

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引用次数: 0

Exploring graphdiyne - Dynamic characterisation of the surface oxidation mechanisms via ReaxFF-MD and experiments 探索石墨二炔--通过 ReaxFF-MD 和实验对表面氧化机制进行动态表征

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-07 DOI: 10.1016/j.carbon.2024.119793

Q. Chen , I.M. De Cachinho Cordeiro , W. Yang , A.C.Y. Yuen , T.B.Y. Chen , W. Wang , W. Yang , G.H. Yeoh , R.K.K. Yuen

Graphdiyne (GDY) is an emerging two-dimensional carbon allotrope comprising unique sp¹ and sp² hybridisation, which has attracted extensive investigation into various applications, especially as battery component materials owing to its excellent electromechanical properties. However, GDY's thermal stability and oxidation behaviour have yet to be evaluated, which is crucial to safety in high-energy applications. The present study characterised the thermophysical properties of GDY via reactive molecular dynamics (MD-ReaxFF) and experimental measurement. The oxidation kinetics and decomposition behaviour were elucidated and benchmarked with graphene (GP) and graphyne (GY) to investigate the correlation between thermal stability and morphology of carbon nanomaterials. The simulation results revealed the initial oxidation mechanism of GDY sheets, where the cleavage of C–C bonds was observed at the acetylenic chain and could be identified as the weak spots of the structural stability. As for oxidation kinetics, GDY's experimental and numerical activation energy was found to be 173.1 and 133 kJ/mol, which is lower than 220.8 kJ/mol of GP. The current work pioneer investigated the thermal stability of GDY using both experimental and numerical approaches. Meanwhile, different oxidation mechanisms between GP and GDY were distinguished and demonstrated in detail.

Graphdiyne（GDY）是一种新兴的二维碳同素异形体，具有独特的 sp1 和 sp2 杂化，由于其出色的机电特性，已吸引了对其各种应用的广泛研究，特别是作为电池组件材料。然而，GDY 的热稳定性和氧化行为尚未得到评估，而这对高能应用的安全性至关重要。本研究通过反应分子动力学（MD-ReaxFF）和实验测量表征了 GDY 的热物理性质。研究阐明了氧化动力学和分解行为，并以石墨烯（GP）和石墨乙烯（GY）为基准，探讨了碳纳米材料的热稳定性与形态之间的相关性。模拟结果揭示了 GDY 片材的初始氧化机制，在乙炔链上观察到了 C-C 键的裂解，这可以确定是结构稳定性的薄弱点。在氧化动力学方面，GDY 的实验和数值活化能分别为 173.1 和 133 kJ/mol，低于 GP 的 220.8 kJ/mol。目前的研究工作率先采用实验和数值方法研究了 GDY 的热稳定性。同时，详细区分并证明了 GP 和 GDY 的不同氧化机制。

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引用次数: 0

The probing of local charge with sulfur encapsulated in single-walled carbon nanotubes 用封装在单壁碳纳米管中的硫探测局部电荷

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-07 DOI: 10.1016/j.carbon.2024.119806

Alexander A. Tonkikh , Dmitry V. Rybkovskiy , Andrey N. Enyashin , Ekaterina A. Obraztsova , Nguyen Van Chuc , Elena D. Obraztsova

In this study, we demonstrated the remarkable sensitivity to electrochemical local charge of sulfur chains encapsulated in small-diameter single-walled carbon nanotubes (S@SWCNTs). To perform micro- and macro-spectroscopic probing, a transparent electrochemical cell was designed in which the charging electrode is formed based on S@SWCNTs. During a short-term electrochemical charging, significant reversible changes were observed in-situ in both Raman and UV–vis-Nir spectra of S@SWCNTs. The optical response was found to depend on the magnitude and sign of the charge, as well as on the duration of the electrochemical charging process at a given potential. The enhanced Raman modes of sulfur chains exhibited a notable linear shift (up to 10 cm-1) accompanied by a redistribution of their intensities. A correlation is identified of the chronoamperometry curve (charging current versus time) and transformations of the Raman spectrum of single-atom sulfur chains. Atomistic simulations allowed to attribute these changes in the Raman spectrum to the softening of the sulfur bonds upon charging. Our findings revealed that the nanotube inhibits the chemical interactions between encapsulated sulfur and local charge sources, thus rendering S@SWCNTs suitable for repeated utilization in local charge analysis.

在这项研究中，我们证明了封装在小直径单壁碳纳米管（S@SWCNTs）中的硫链对电化学局部电荷的显著敏感性。为了进行微观和宏观光谱探测，我们设计了一个透明的电化学电池，其中的充电电极是以 S@SWCNTs 为基础形成的。在短期电化学充电过程中，S@SWCNTs 的拉曼光谱和紫外-可见-氖光谱都发生了显著的原位可逆变化。研究发现，光学响应取决于电荷的大小和符号，以及在给定电位下电化学充电过程的持续时间。硫链的增强拉曼模式表现出明显的线性偏移（高达 10 cm-1），并伴随着其强度的重新分布。计时器曲线（充电电流与时间）与单原子硫链拉曼光谱的变化之间存在相关性。通过原子模拟，可以将拉曼光谱的这些变化归因于充电时硫键的软化。我们的研究结果表明，纳米管抑制了封装硫和局部电荷源之间的化学作用，从而使 S@SWCNTs 适合在局部电荷分析中重复使用。

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引用次数: 0

The quantum mechanical origin of the supercapacitance phenomenon in reduced graphene oxide structures 还原氧化石墨烯结构中超级电容现象的量子力学起源

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-07 DOI: 10.1016/j.carbon.2024.119736

Thamyres F.M. Moreira, Edgar F. Pinzón, Adriano dos Santos, Laís C. Lopes, Paulo R. Bueno

We investigated supercapacitance phenomena observed in reduced graphene oxide structures from a quantum mechanical rate viewpoint. The supercapacitance phenomenon in carbonaceous materials has been majorly attributed to electrostatic capacitance contributions, in which the magnitude of this capacitance is correlated with the amount of surface area available to be charged under the presence of electric potential perturbations. Nonetheless, the quantum rate theory predicts a superposition between electrostatic

C_{e}

and chemical

C_{q}

(also called quantum) capacitance energetic levels. The superposition of these capacitive states implies that the electric potential perturbation not only drives the separation of charges in space (thus correlating with the geometry of the capacitor and consequently with the surface area) but also governs the occupancy of the electric-field screened electronic structure of reduced graphene oxide embedded in the electrolyte environment. This leads to an energy degeneracy between electrostatic

e^{2} / C_{q}

and quantum

e^{2} / C_{q}

capacitive energy states, as confirmed in this work for reduced graphene oxide carbonaceous structures. Accordingly, the analysis proves that the charge dynamics associated with the resistance for charging the pseudo-capacitive

E = e^{2} / C_{q}

states of reduced graphene oxide structure follows a quantum resistance limit

R_{K} = h / e^{2} \sim 25.8

k

Ω

within a charging frequency of

ν = 1 / R_{K} C_{q} = E / h = e^{2} / h C_{q}

that obeys quantum electrodynamics principles, in agreement with the premises of the quantum rate theory. Two energy levels associated with the occupancy of the electronic states upon the reduction of graphene oxide were identified.

我们从量子力学速率的角度研究了在还原氧化石墨烯结构中观察到的超级电容现象。碳质材料中的超电容现象主要归因于静电电容的贡献，其中静电电容的大小与存在电势扰动时可带电的表面积相关。然而，量子速率理论预测了静电电容 Ce 和化学电容 Cq（也称为量子）能级之间的叠加。这些电容态的叠加意味着，电势扰动不仅会驱动空间中的电荷分离（因此与电容器的几何形状相关，进而与表面积相关），而且还会控制嵌入电解质环境中的还原氧化石墨烯的电场屏蔽电子结构的占用率。这就导致了静电 e2/Cq 和量子 e2/Cq 电容能态之间的能量退化，这一点在本研究中的还原氧化石墨烯碳质结构中得到了证实。因此，分析证明，与还原氧化石墨烯结构的伪电容性 E=e2/Cq 态充电电阻相关的电荷动力学遵循量子电阻极限 RK=h/e2∼25.8 kΩ，充电频率为 ν=1/RKCq=E/h=e2/hCq，符合量子电动力学原理，与量子速率理论的前提一致。确定了氧化石墨烯还原时与电子状态占据有关的两个能级。

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引用次数: 0

In-situ grown NiFeLDH nanosheets over nitrogen rich amorphous carbon nanotubes: An electrochemical sensing platform for the detection of depression biomarker 富氮无定形碳纳米管上原位生长的 NiFeLDH 纳米片：用于检测抑郁生物标记物的电化学传感平台

IF 10.5 2区材料科学 Q1 CHEMISTRY, PHYSICAL

Carbon

Pub Date : 2024-11-07 DOI: 10.1016/j.carbon.2024.119807

Narmatha Sivaraman , Rithanya Kanagaraj , Rangasamy Thangamuthu

In this work, intrinsic conductivity mismatch of NiFe layered double hydroxide (NFL) catalysts and agglomeration of nanosheets were addressed by introducing N doped carbon nanotubes (NCNTs) which improves catalytic activity. Using a one-step wet chemical process, CNT-supported NiFeLDH nanosheets (NFL/NCNT_x, x = 20, 50 and 100) were effectively created. This work delves into the lower level sensitive electrochemical detection of serotonin (5-HT) by utilizing synergy of CNT and LDH. The modified NFL/NCNT exhibits better electrochemical activity, appreciable sensitivity and spanned a concentration range of 0.01–400 μM with detection limit stood at 1.2 nM due to the plethora of electrochemical active surface area, remarkable conductivity and appreciable stability. Impressively, 96.0–96.8 % and 96.7–97.2 % recovery rates achieved in human urine and serum samples were well close to HPLC data, signifying its feasibility for real-time monitoring. The operational stability of the proposed sensor retained up to 89.13 % for 6 weeks. The present study highlights that tailoring NFL-NCNT heterojunction is an important strategy for the development of active and stable sensing platform.

在这项工作中，通过引入掺杂 N 的碳纳米管（NCNTs），解决了镍铁层双氢氧化物（NFL）催化剂的内在电导率失配和纳米片的团聚问题，从而提高了催化活性。通过一步湿化学工艺，有效地制备出了 CNT 支持的 NiFeLDH 纳米片（NFL/NCNTx，x = 20、50 和 100）。这项研究利用 CNT 和 LDH 的协同作用，深入研究了血清素（5-HT）的低级灵敏度电化学检测。改性后的 NFL/NCNT 具有更高的电化学活性和灵敏度，其电化学活性表面积大、电导率高、稳定性好，检测浓度范围为 0.01-400 μM，检测限为 1.2 nM。令人印象深刻的是，在人体尿液和血清样本中实现的 96.0%-96.8% 和 96.7%-97.2% 的回收率与 HPLC 数据非常接近，这表明了其用于实时监测的可行性。拟议传感器的操作稳定性在 6 周内保持了 89.13%。本研究表明，定制 NFL-NCNT 异质结是开发主动、稳定传感平台的重要策略。

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