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Herein, we propose a simple and eco-friendly strategy based on laser direct writing technology to regulate the valence state of Mn-based oxides nanoparticles anchored on three-dimensional(3D) framework of laser-induced graphene (LIG) for the application of high-performance flexible planar interdigital microsupercapacitors (MSCs). Under the laser radiation, a polyimide (PI) and MnO 2 composite film was directly converted into 3D graphene and MnO x (MnO, MnO 2 and Mn 3 O 4 mixture). Furthermore, the results reveal that LIG/MnO x MSCs device exhibits a high specific capacitance of 23.3 mF cm−2, which is about 29 times higher than that of LIG MSCs (0.8 mF cm−2). Moreover, LIG/MnO x MSCs possess a high energy density of 7.28 μWh cm−2, outstanding cycle stability with the capacitance retention rate of 97.4 % after 10,000 cycles, and excellent mechanical flexibility. Therefore, this preparation strategy of LIG/MnO x provides a reference for the performance regulation of Mn-based oxides and the low-cost construction of MSCs devices with high energy density, which carries significant research implications for diverse flexible wearable electronic applications in the forthcoming days. [Display omitted] • It provides a green and effective strategy for rapid complexation of metal oxides in graphene. • The LIG/MnO x MSCs shows a a wide working voltage window from 0 to 1.5 V. • It provides high specific capacitance of 23.3 mF cm−2 and an energy density of 7.28 μWh cm−2. • The LIG/MnO x MSCs have excellent mechanical properties and application potential. • This strategy opens up a simple and versatile method for the preparation of graphene-based composites. [ABSTRACT FROM AUTHOR]

Two kinds of porous carbon and magnetic particles-based composite nanofibers (PCNTF-CoFe and PCNTF-NiFe) were synthesized for electromagnetic wave (EMW) absorption. Magnetic particles were used as the catalyst to increase the crystallinity of carbon and the corresponding dielectric loss ability, while porous structure was designed to improve the impedance matching. According to the results, the dielectric loss abilities of PCNTF-CoFe and PCNTF-NiFe are enhanced without significant degradation in their impedance matching condition. Therefore, through the polarization and conduction-induced dielectric loss together with the natural and exchange resonance-induced magnetic loss, the incident EMW can be attenuated rapidly inside PCNTF-CoFe and PCNTF-NiFe. PCNTF-CoFe shows a minimum reflection loss (RL min) of −54.6 dB and effective band width (RL≤-10 dB, EABW) of 6.0 GHz at 2.0 mm, while PCNTF-NiFe shows RL min of −33.4 dB and EABW of 5.7 GHz at 1.7 mm. Consequently, PCNTF-CoFe and PCNTF-NiFe can be promising candidates for application in EMW absorption. [Display omitted] • Two kinds of carbon nanofiber-based composites were designed for EMW absorption. • The conduction loss ability was enhanced due to a higher crystallinity of carbon. • CNTs were generated on carbon nanofiber under the catalyzation of MNPs. • PCNTF-CoFe and PCNTF-NiFe have a hierarchical structure. • PCNTF-CoFe and PCNTF-NiFe can be promising candidates for EMW absorption. [ABSTRACT FROM AUTHOR]

This paper proposes a simple and rapid microwave-assisted phosphorus-oxygen doped porous carbon (P/O-PC) preparation strategy is proposed using potassium citrate, Phytic acid (PA), and ethanol under air atmosphere. PA can be used as both a phosphorus source and a microwave absorbing agent. The P/O-PC500–0.75 has a large specific surface area of 905 cm2/g. P/O doping introduces defects into the carbon structure, which enhances the capacitance of the porous carbon. The P/O-PC500–0.75 demonstrates excellent capacitance values of 330 F/g and 389.4 F/g in 6.0 M KOH and 1.0 M H 2 SO 4 , respectively (1 A/g). In addition, the symmetrical supercapacitors assembled with the P/O-PC500–0.75 exhibit good electrochemical stability over 5000 cycles at 5 A/g, with a capacitance loss of only 3.6%. This microwave-assisted strategy offers simplicity in operation and low energy consumption, providing a new and efficient pathway to prepare carbon materials in a fast and simple manner. [Display omitted] [ABSTRACT FROM AUTHOR]

Complex service conditions often cause corrosion, rendering most microwave absorbers ineffective. Consequently, the development of bifunctional materials with exceptional properties in terms of both anti-corrosion and microwave absorption is of utmost importance. In this study, vanadium nitride nanofiber @ N-doped carbon (VN-F@NC) composite material with excellent microwave absorption and anti-corrosion was synthesized by combining V 2 O 5 precursor fibers encapsulated in polydopamine with ammonia reduction nitriding process. The amorphous N-doped carbon nanolayer, residual O element, and porous structure of VN-F@NC contribute to impedance matching, interfacial polarization, as well as multiple reflections and scattering. As a result, VN-F@NC exhibits strong microwave absorption ability in multiple bands, with optimal reflection loss of − 40.0 dB, − 63.6 dB, and − 52.5 dB in the C, X, and Ku bands, respectively. Moreover, the encapsulation of VN nanofibers with the N-doped carbon nanolayers protects them from corrosion, thereby increasing the polarization resistance to 3.61 × 105 Ω·cm2 and reducing corrosion current to 9.00 × 10-8 A/cm2. Therefore, the encapsulation of vanadium nitride fibers with N-doped carbon nanolayer emerges as a viable approach in enhancing the microwave absorption capabilities as well as the resistance against corrosion of absorbers. [Display omitted] [ABSTRACT FROM AUTHOR]

It is essential for developing an effective and accurate method for analysis for detecting 4-nitrophenol (4-NP), as its harmful effect is one of the most frequent environmental concerns. In this work, the 4-NP was detected by the CNF/CZO nanocomposite. The cobalt-doped zinc oxide (CZO) was synthesized utilizing a simple hydrothermal technique and carbon nanofiber (CNF) was combined with cobalt-doped zinc oxide (CZO) to get CNF/CZO nanocomposite. The morphological and chemical characteristics of the CNF|CZO nanocomposite have been studied using several characterization techniques. The CZO nanoparticles have equal dispersion across the surface of the CNF and the nanocomposites were modified with a glassy carbon electrode (GCE), which is utilized as a working electrode for the electrochemical studies. Hence, the CNF|CZO the nanocomposite was confirmed using field emission scanning electron microscopy, Transmission Electron Microscopy, Energy Dispersive X-ray analysis, X-ray Diffraction Analysis, and X-ray Photoelectron Spectroscopy, Fourier-transform infrared spectroscopy, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry research, and Differential Pulse Voltammetry studies were done. Hence, the GCE|CNF|CZO electrode displays a low detection limit of 0.2 μM, a wide linear response range of 0.01–520 µM, and a higher sensitivity of 0.0137 μA μM−1 cm−2. Further, the GCE|CNF|CZO electrode detected 4-NP in environmental water samples and also showed exceptional selectivity, repeatability, stability, and reproducibility. Hence, we conclude that GCE|CNF|CZO electrode exhibited good catalytic activity due to the inherent interaction between CNF and CZO providing an electron transfer network and high catalytic activity towards 4-NP detection. [Display omitted] • The GCE|CNF|CZO electrodes applied for the detection of 4-NP in environmental water samples. • Cobalt-doped Zinc Oxide (CZO) was synthesized by hydrothermal method. • The GCE|CNF|CZO exhibited 4-NP detection limit was LOD of 0.2 μM with wide linear response range of 0.01-520 µM. • The electrode sensitivity was identified as 0.0137 µA µM−1 cm−2. • The practical applicability of the electrode was tested in environmental water samples. [ABSTRACT FROM AUTHOR]

The utilization efficiency of single atoms is limited by the active sites being buried in support. To maximize atom utilization, Cu single atoms are anchored on the external surface of g-C 3 N 4 nanofibers (CNNFs), which are fabricated by partial thermal decomposition and subsequent self-assembly in H 2 O. The abundant N and O-containing functional groups of CNNFs are vital for the loading of Cu. Benefited from the full utilization of Cu sites, CNNF-Cu exhibits excellent Fenton-like catalytic activity for Methylene Blue degradation. The reaction kinetic constant is more than 10 times higher than that of the traditional single-atom catalyst with Cu sites evenly distributed throughout the entire support. CNNF-Cu maintains most of its catalytic activity after five cycle tests, suggesting good stability. This work provides a convenient method to maximize the utilization of single metal atoms for catalytic applications. [Display omitted] • Partial pyrolysis and assembly of g-C 3 N 4 generated nanofibers of ∼15 nm in diameter. • N- and O-containing groups were formed on the surface of the nanofibers. • Functional groups can anchor Cu single atoms on the surface to form CNNF-Cu. • CNNF-Cu showed full atom utilization and satisfactory activity for MB degradation. [ABSTRACT FROM AUTHOR]