Capacitive deionization (CDI) represents a novel technology for the desalination and purification of seawater. Selecting the appropriate electrode material is crucial, with carbon electrodes frequently employed owing to their high specific surface area, extensive porous structure, and environmentally sustainable nature. This study presents a nitrogen-doped porous carbon, derived from household waste, which demonstrates outstanding electrochemical and desalination performance. The purified chitosan was mixed with a specific ratio of CaCO3 and carbonized at 800 °C to produce chitosan porous carbon (CPC-T). To verify the role of the templating agent, its performance was compared with chitosan porous carbon (CPC) prepared by direct carbonization. CPC-T possesses more mesoporous structures (31.25%), shortening ion transport pathways and significantly enhancing charge transfer rates. The nitrogen-rich doping (8.65 at%) provides numerous active sites and excellent conductivity, making it highly appropriate for capacitive deionization applications. Compared to CPC prepared without a templating agent, CPC-T has a higher specific capacitance (101.5 F g− 1 at a scan rate of 2 mV s− 1) and good cycling stability. The CDI cell made from it exhibits a salt adsorption capacity (SAC) of 25.8 mg g− 1 for 500 mg L− 1 NaCl solution at an applied voltage of 1.4 V, retaining 88% capacity after 50 adsorption–desorption cycles, demonstrating excellent desalination regeneration performance. Additionally, among different concentrations of salt solutions, the CPC-T material shows the best desalination performance for the test solution at a concentration of 500 mg L− 1. For different solute ions, the CDI cell with this material as the electrode exhibits excellent desalination performance for Ca2+, with a SAC value of up to 34.02 mg g− 1. This is a self-doped porous carbon material that significantly outperforms traditional carbon-based materials.

Incorporation of pseudocapacitive materials into porous carbon is a promising strategy to boost electrochemical performance. Herein, composite of biomass-derived porous carbon and MnO2 (a typical pseudocapacitive material) was facilely fabricated through an in-situ synthesis approach with sorghum seeds derived porous carbon (SSC) as the skeleton for MnO2 deposition. The as-prepared composite ( MnO2@SSC) exhibits hierarchical porous structure with abundant interlaced MnO2 nanowires wrapping on the surface. While the porous structure is beneficial to the active sites exposure and electrolyte ions transport, the interlaced three-dimensional (3D) network of MnO2 nanowires significantly boosts the tolerance toward volume shrinkage/expansion during the cyclic process. Consequently, the MnO2@ SSC-based electrode delivered quite promising supercapacitive performance including superior specific capacitance of 482.7 F/g at 0.5 A/g, outstanding long-term cycling stability (95.8% specific capacitance retention after 20,000 cycles) and high energy density of 13.7 Wh/kg at power density of 298.1 W/kg. Furthermore, all-solid-state flexible supercapacitor based on MnO2@ SSC can be facilely bent to various angles (0° to 150°) without significant degradation in the capacitive performance. This study provides a facile, cost-effective, and sustainable approach for the fabrication of high-performance electrode materials.

The high value-added utilization of traditional coal resources is one of the important ways to achieve the strategic goals of carbon peaking and carbon neutrality. Simultaneously, coal-based carbon materials, noted for their cost-effectiveness, superior conductivity, and inherent stability, are emerging as promising candidates for next-generation capacitor technologies. This research presents a series of coal-derived porous carbon by pyrolysis using low rank lignite as raw material and KOH as activator, which are employed in symmetrical supercapacitors filled with liquid electrolytes. The physicochemical properties of the as-prepared electrode materials are characterized by means of scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and their supercapacitive performance are evaluated through cyclic voltammetry and galvanostatic charge–discharge tests. The coal-based porous carbon electrode prepared at an activation temperature of 800 °C (KOH-800) exhibits a specific capacitance of 142.2 F g− 1 at a current density of 1 A g− 1, and retaining 80% of its capacitance (114.0 F g− 1) even at 10 A g− 1. The fabricated liquid supercapacitor displays a power density of 999.8 W kg− 1 and an energy density of 19.4 Wh kg− 1 at a current density of 1 A g− 1. Undergoing 10,000 cycles at 2 A g− 1, the supercapacitor maintains nearperfect capacitance retention and coulombic efficiency close to 100%, demonstrating its excellent durability and stability for supercapacitor applications.

The high-rate performance of lithium/fluorinated carbon (Li/CFx) battery remains a challenge due to poor discharge dynamics behavior accompanied by the overheating issue. We developed a novel fluorinated reed-carbon with three-dimensional (3D) porous channels to favor discharge dynamics behavior achieving excellent discharge performance as high as 5 C. Typically, the preparation of fluorinated reed-carbon mainly involves three steps, namely, crushing into powders, pre-carbonization of reed and precise fluorination. During the fluorination process, we precisely controlled the fluorination temperature in range of 330–370 °C and gas ratio ( F2 of ~ 15 vol%) to optimize the fluorine carbon ratio. This kind of CFx possesses the novel structure at the scale of micron level ranging from 0.5 to 3 μm, which favors the electrolyte and charge transport through the channels smoothly. This 3D porous structure increases the specific surface area of the CFx material, providing more chemical reaction sites to enhance discharge dynamics behavior and effectively hinder the volume expansion of batteries, which is conductive to improve the high-rate performance of Li/CFx battery. This low-cost and facile approach opens up a novel pathway to design carbon materials and CFx for Li/CFx battery.

Considering the intrinsic activity of non-precious metal oxygen reduction reaction (ORR) catalysts is typically lower than that of precious metal catalysts, it is crucial to focus on the rational design of their micro-morphology and active site. This paper employed a simple molten salt-mediated template method to fabricate a Fe3C composite N-doped C catalyst with a layered porous framework ( Fe3C@NC). Tannic acid was utilized to form a strong coordination with iron to limit the grain size of Fe3C nanocrystals generated by high-temperature pyrolysis. Moreover, urea achieved nitrogen doping in tannic acidderived porous carbon, while the graphite phase nitrogen-doped carbon (g-C3N4) formed by its pyrolysis, together with the molten salt-mediated environment, jointly controlled the two-dimensional sheet-like structure of the material. The optimized Fe3C@ NC-800 demonstrated efficient ORR performance, with an ORR half-wave potential of 0.883 V. Its application as a cathode catalyst in a liquid zinc-air battery (ZABs) exhibits a maximum power density of 211.5 mW cm− 2, surpassing that of a Pt/C-based ZAB and indicating the potential practical utility of this material.

본 연구의 목적은 복층 배수성·저소음 아스팔트 포장의 공용수명 예측과 경제성 분석에 있다. 성능평가를 위한 현장시 험은 투수시험 및 소음 측정을 실시하였으며, 실내시험은 반사균열, 동탄성계수, 소성변형(FN) 시험을 진행하였다. 성능 평가 결과를 기반으로 포장설계 수명 예측 및 비용 편익 분석을 수행하였으며, 이를 일반 밀입도 포장의 비용 편익과 비 교·분석하여 복층 배수성·저소음 아스팔트 포장의 경제성을 확인하고자 하였다. 성능평가 결과 복층 배수성·저소음 포장 이 일반 밀입도 포장과 비교 시 소음 저감 성능에서 매우 우수한 결과를 나타내었다. 비용 편익 분석 결과 복층 배수성· 저소음 아스팔트 포장은 높은 초기비용에도 불구하고 설계기간동안 낮은 유지보수 비용을 가지며 안전 및 소음 측면에 서 일반 밀입도 포장과 비교 시 매우 경제적인 것으로 나타났다. 총 비용과 총 편익 비용을 편익 비용 비율(BCR)로 계 산한 결과 복층 배수성·저소음 아스팔트 포장이 단위 비용 당 편익 측면에서 방음벽이 있는 다른 포장에 비해 가장 우수 한 결과를 보였다.

Porous carbon has been intensively used for microwave absorption in merits of its outstanding specific surface area and dielectric properties. This study investigates the microwave absorption capacity of saturated wood-based activated carbon (SWAC) which was used for methylene blue treatment. The results demonstrate that SWAC, subjected to high temperature calcination, exhibits excellent microwave absorption properties. The structure, composition, micro-morphology, and electromagnetic parameters of SWAC were comprehensively analyzed using various techniques. The findings reveal that after calcination, SWAC possesses a rich pore structure, optimized material impedance matching, and the introduction of N atoms from the organic substance methylene blue into the carbon lattice of SWAC, thereby providing dipole polarization loss. These properties significantly contribute to its microwave absorption performance. The optimal reflection loss of SWAC at 6 GHz reaches −50.29 dB with an effective absorption bandwidth of 2.01 GHz, achieved at a calcination temperature of 700 °C and a paraffin matrix additive amount of 25%. The one-step treatment of SWAC proves to be a competitive and cost-effective method for producing microwave absorbers, which holds significant importance for the recovery of SWAC.

Biomass-derived carbon materials have attracted considerable attention in electromagnetic wave (EMW) absorption applications due to their advantages of low cost, light weight, and sustainability. Herein, bagasse-based porous carbon (BPC) was prepared by canonization and activation process from natural waste bagasse. The porous flower-like MoS2/ BPC composites were successfully prepared for efficient microwave absorption via hydrothermal process by in-situ formation of flower-like MoS2 into the porous structure of BPC. The effect of hydrothermal time and hydrothermal temperature on surface morphology, degree of graphitization, surface chemical composition and impedance matching of the prepared samples was investigated. Results demonstrated that when the hydrothermal temperature was 220 °C, and the hydrothermal time was 24 h, the obtained MoS2/ BPC sample (named as MoS2/ BPC-220 ℃) showed the minimum reflection loss value (RL) of − 41.6 dB at 8.96 GHz and exhibited effective microwave absorption bandwidth (EAB) of 4.32 GHz at a relatively thin thickness of 1.5 mm. This work provides a promising way to prepare novel biomass-derived porous carbon for strong broadband electromagnetic absorption.

Battery electrodes, essential for energy storage, possess pores that heavily influence their mechanical properties based on the level of porosity and the nature of the pores. The irregularities in pore shape, size, and distribution complicate the accurate determination of these properties. While stress-strain measurements can shed light on a material’s mechanical behavior and predict compression limits, the complex structure of the pores poses significant challenges for accurate measurements. In this research, we introduce a simulation-driven approach to derive stress-strain data that considers porosity. By calculating relative density and the rate of volume change under compression based on porosity, and applying pressure, we conducted a parametric study to identify the elastic modulus (E) in relation to the rate of volume change. This information was utilized within a material modeling equation, generating stress-strain (S-S) curves that were further analyzed to replicate the compression behavior of the electrode material. The outcomes of this study are expected to improve the prediction accuracy of mechanical properties for porous electrode materials, potentially enhancing battery performance and refining manufacturing processes.

A substantial quantity of discarded tires has inflicted harm on the environment. Microwave pyrolysis of discarded tires emerges as an efficient and environmentally friendly method for their recycling. This research innovatively utilizes the characteristics of microwave rapid and selective heating to pyrolyze waste tires into porous graphene under the catalysis of KOH etching. Moreover, this study comprehensively investigates the dielectric characteristics and heating behavior of waste tires and different proportions of waste tire–KOH mixtures. It validates the preparation of graphene through KOH-catalyzed microwave pyrolysis of waste tires, tracking morphological and structural changes under varying temperature conditions. The results indicate that optimal dielectric performance of the material is achieved at an apparent density of 0.68 g/cm3 at room temperature. As the temperature increases, the dielectric constant gradually rises, particularly reaching a notable increase around 700 °C, and then stabilizes around 750 °C. Additionally, the study investigates the penetration depth and reflection loss of mixtures with different proportions, revealing the waste tire–KOH mass ratio of 1:2 demonstrates favorable dielectric properties. This research highlights the impressive microwave responsiveness of the waste tire–KOH mixture, Upon the addition of KOH, the mixed material exhibits an augmented dielectric constant and relative dielectric constant, supporting the viability of KOH-catalyzed microwave pyrolysis for producing porous graphene from waste tires. This method is expected to provide a new method for the valuable reuse of waste tires and a technology for large-scale, efficient and environmentally friendly production of graphene.

For metal-free carbocatalysts, heteroatom doping and hierarchically porous structure are the significant factors to improve their catalytic performances. Herein, N-, P-co-doped hierarchically porous carbon fiber (NPC–2–800) was prepared by pyrolyzing bamboo pulp in combination with ( NH4)2HPO4 and activator K2CO3. It was found that ( NH4)2HPO4 not only provides N and P atoms, but also significantly affect the morphology and pore structure of the porous carbon. An appropriate dosage of ( NH4)2HPO4 facilitates the formation of hierarchically porous carbon fiber in NPC-2–800. Whereas, the carbon fragments with only micropores were obtained in absence of ( NH4)2HPO4. The hierarchical porosity and the co-doping of N and P atoms in the NPC-2–800 contribute to its outstanding catalytic performances in the 4-Nitrophenol (4-NP) reduction assisted by NaBH4. The NPC-2–800 exhibits an attractive turnover frequency (TOF) value of 4.29 × 10– 4 mmol mg− 1 min− 1, a low activation energy (Ea) of 24.76 kJ/mol, and an acceptable recyclability for 7 cycles without obvious decrease in activity. Kinetics analyses suggest that the 4-NP reduction proceeds through the Langmuir–Hinshelwood model. In addition, the NPC-2–800 can also efficiently catalyze the 2-NP and 3-NP reduction. Moreover, in the real water body, the NPC-2–800 also showed superior catalytic activity to catalyze 4-NP reduction. This study provides an efficient catalyst for pollutant conversion and elimination as well as guidelines for designing versatile carbon-based catalysts.