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.

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.

The raw material selected for this research was Brazil chestnut shells (BCs), which were utilized to gain porous carbon as a positive electrode for lithium–sulfur batteries (LSBs). The effects of N/S co-doped on the electrochemical properties of porous carbon materials were studied using thiourea as nitrogen and sulfur sources. The experimental results indicate that the N/S co-doped carbon materials have a higher mesopore ratio than the undoped porous carbon materials. The porous carbon material NSPC-2 has a lotus-like structure with uniform pore distribution. The N and S doping contents are 2.5% and 5.4%. The prepared N/S co-doped porous carbon materials were combined with S, respectively, and three kinds of sulfur carbon composites were obtained. Among them, the composite NSPC-2/S can achieve the initial specific discharge capacity of 1018.6 mAh g− 1 at 0.2 C rate. At 1 C rate, the initial discharge capacity of the material is 730.6 mAh g− 1, and the coulomb efficiency is 98.6% and the capacity retention rate is 71.5% after 400 charge–discharge cycles.

In this study, we developed a facile and template-free strategy for the preparation of activated porous carbon beads (APCBs) from polyacrylonitrile. The chemical activation with KOH was found to enhance the pore properties, such as specific surface area (SSA), pore volume, and pore area. The APCBs exhibited a large SSA of 1147.99 m2/g and a pore area of 131.73 m2/g. The APCB-based electrodes showed a good specific capacitance of 112 F/g at 1 A/g in a 6 M KOH electrolyte, and excellent capacitance retention of 100% at a current density of 5 A/g after 1000 cycles. Therefore, the APCBs prepared in this study can be applied as electrode materials for electric double-layer capacitors.

The stereotype of flexible MOFs(Amino-MIL-53) and carbonized porous carbon prepared from renewable resources is successfully synthesized for CO2 reduction application. The textural properties of these microporous materials are investigated, and their CO2 storage capacity and separation performance are evaluated. Owing to the combined effects of CO2-Amino interaction and its flexibility, a CO2 uptake of 2.5 mmol g−1 is observed in Amino-MIL-53 at 20 bar 298 K. In contrast, CH4 uptake in Amino-MIL-53 is very low up to 20 bar, implying potential sorbent for CO2/CH4 separation. Carbonized samples contain a small quantity of metal residues(K, Ca, Mg, S), resulting in naturally doped porous carbon. Due to the trace metal, even higher CO2 uptake of 4.7 mmol g−1 is also observed at 20 bar 298 K. Furthermore, the CH4 storage capacity is 2.9 mmol g−1 at 298 K and 20 bar. To evaluate the CO2 separation performance, the selectivity based on ideal adsorption solution theory for CO2/CH4 binary mixtures on the presented porous materials is investigated.

Monolithic carbon foams with hierarchical porosity were prepared from polyurethane templates and resol precursors. Mesoporosity was achieved through the use of soft templating with surfactant Pluronic F127, and macroporosity from the polyurethane foams was retained. Conditions to obtain high porosity materials were optimized. The best materials have high specific surface areas (380 and 582 m2 g–1, respectively) and high electrical conductivity, which make them good candidates for supports in sensors. These materials showed an almost linear dependence between the potential and the pH of aqueous solutions.

Porous carbon materials synthesized from various plant derived precursors i.e. seeds of [Castor (Ricinus communis), Soap nut (Sapindus sp.), Cashew-nut (Semecarpus anacardium), Jack fruit (Artocarpus heterophyllus), Safflower (Carthamus tinctorius), Ambadi (Crotolaria juncea), Neem (Azadirachta indica), Bitter Almond (Prunus amygdalus), Sesamum (Sisamum indicum), Date-palm (Phoenix dactylifera),Canola (Brassica napus), Sunflower (Helianthus annulus)] and fibrous materials from [Corn stem- (Zea mays), Rice straw (Oryza sativa), Bamboo (Bombax bambusa) and Coconut fibers (Cocos nucifera)] were screened to make supercapacitor in 5M KOH solution. Carbon material obtained from Jack fruit seeds (92.0 F/g), Rice straw (83.0 F/g), Soap nut seeds (54.0 F/g), Castor seeds (44.34 F/g) and Bamboo (40.0 F/g) gave high capacitance value as compared to others. The magnitude of capacitance value was found to be inversely proportional to the scan rate of measurement. It is suggested that carbon material should possess large surface area and small pore size to get better value of capacitor. Moreover, the structure of carbon materials should be such that majority of pores are in the plane parallel to the plane of electrode and surface is fluffy like cotton ball.

Porous carbon materials were prepared with a thermal treatment of coal tar pitch at 550 in the Ar gas. Growth, merger, and distribution of pore were characterized with scanning electron microscopy as variation ascending temperature gradient and chamber pressure. After graphitizing at the 2600 (1 hr.), walls and connecting parts between pores were investigated with X-ray diffraction patterns. Wall thickness and pore size decreases as increasing ascending temperature gradient, and pore size becomes homogeneous. Graphite quality and thermal conductivity become higher due to the enhanced orientation of walls and connecting parts between pores.