Gamma-induced interconnected networks in microporous activated carbons from palm petiole under NaNO3 oxidizing environment towards high-performance electric double layer capacitors (EDLCs)

Abstract Activated carbons (ACs) were developed from palm petiole via a new eco-friendly method composed of highly diluted H2SO4 hydrothermal carbonization and low-concentration KOH-activating pyrolysis followed by gamma-induced surface modification under NaNO3 oxidizing environment. The prepared graphitic carbons were subsequently used as an active material for supercapacitor electrodes. The physiochemical properties of the ACs were characterized using field emission scanning electron microscope–energy dispersive X-ray spectroscopy, N2 adsorption/desorption isotherms with Brunauer–Emmett–Teller surface area analysis, Fourier transform infrared spectroscopy, X-ray diffraction and Raman spectroscopy. The electrochemical performance of the fabricated electrodes was investigated by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. Even treated with extremely low H2SO4 concentration and small KOH:hydrochar ratio, the maximum SBET of 1365 m2 g−1 for an AC was obtained after gamma irradiation. This was attributed to radiation-induced interconnected network formation generating micropores within the material structure. The supercapacitor electrodes exhibited electric double-layer capacitance giving the highest specific capacitance of 309 F g−1 as well as excellent cycle stability within 10,000 cycles. The promising results strongly ensure high possibility of the eco-friendly method application in supercapacitor material production

Activated carbon derived from radiation-processed durian shell for energy storage application

A lignocellulosic biomass, durian shell, modified by radiolytic oxidizing species from gamma and electron beam irradiations, has been used as a starting material for activated carbon (AC) production. Facile hydrothermal carbonization with ZnCl2/FeCl3 and physical activation were employed in addition. The physicochemical and energy storage properties of the graphitic carbons were investigated using Field Emission Scanning Electron Microscope (FESEM), N2 adsorption-desorption, Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Raman spectroscopy, Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS). Biomass modification by radiolytic oxidizing species aided in improving the energy storage properties of the resultant ACs without significantly changing the textural qualities. The radiation type played an important role on the surface functional groups, basal plane, and pore structures of the graphitic materials. The energy storage mechanism was based on a combination of EDLC and pseudo capacitances with high Coulombic efficiency. The highest specific capacitance obtained was 325.20 F/g providing capacity retention of 94.79 % after 10,000 cycles. A promising method of AC production for energy storage application has therefore been successfully demonstrated

Structural and Electrochemical Evolution of Water Hyacinth-Derived Activated Carbon with Gamma Pretreatment for Supercapacitor Applications

This study introduces a gamma pretreatment of water hyacinth powder for activated carbon (AC) production with improved electrochemical properties for supercapacitor applications. The structural and morphological changes of post-irradiation were meticulously analyzed using scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). The pretreatment significantly modifies the pore structure and reduces the particle size of the resulting activated carbon (WHAC). Nitrogen adsorption-desorption isotherms indicated a substantial increase in micropore volume with escalating doses of gamma irradiation. Electrochemically, the activated carbon produced from pretreated WH at 100 kGy exhibited a marked increase in specific capacitance, reaching 257.82 F g−1, a notable improvement over the 95.35 F g−1 of its untreated counterpart, while maintaining 99.40% capacitance after 7000 cycles. These findings suggest that gamma-pretreated biomasses are promising precursors for fabricating high-performance supercapacitor electrodes, offering a viable and environmentally friendly alternative for energy storage technology development

Engineering antibacterial tannic acid/polyethyleneimine coatings on lithium disilicate glass-ceramics for dental applications

This study introduces an innovative approach to enhance the antibacterial properties of lithium disilicate glass ceramics, widely used in dental restorations. We explored the efficacy of tannic acid (TA) and polyethyleneimine (PEI) as coating agents, capitalizing on a robust defense against microbial colonization and biofilm formation. We employed various analytical techniques, including differential thermal analysis (DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), to characterize the physical, chemical, and antibacterial properties of the TA/PEI coated glass-ceramics. Results indicated a notable improvement in the mechanical properties, such as Weibull modulus, elastic modulus, and fracture toughness of the coated samples. Moreover, the TA/PEI coatings displayed superior thermal stability and effective leaching behavior in different pH, pertinent to dental applications. Significantly, the TA/PEI coatings exhibited high antibacterial activity against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, making them promising candidates for enhancing the bioactivity of dental restorative materials. This study lays the foundation for developing advanced antibacterial coatings for dental applications, aiming to improve patient outcomes in dental care