Avik Denra

Designing electrode materials that are both sustainable and electrochemically effective is essential for the continued advancement of energy storage systems. Herein, seaweed-derived activated carbon (SWAC) was synthesized from Pyropia yezoensis via a facile activation-functionalization strategy using KOH activating agent. Notably, the optimized SWAC-800 (calcined at 800 ℃) sample exhibited an ultrahigh specific surface area of 4224 m2 g⁻1, with porous structure and intrinsic nitrogen functionalities. SWAC-800 delivers a specific capacitance of 549.7 and 224 F g⁻1 at 1.0 A g⁻1 in three electrode and two electrode system, respectively. The symmetric device delivered a high energy density of 31.1 Wh kg⁻1 with excellent long-term cycling stability over 18,000 cycles. Furthermore, symmetric supercapacitors connected in series successfully powered the commercial LEDs for more than 200 s. Systematic regulation of activation temperature enables precise control over pore evolution, resulting in an ultrahigh surface area and an optimized micro/mesoporous architecture. This proposed green and economically viable approach not only promotes the effective utilization of a marine biomass but also offers a pathway for the development of advanced electrode materials toward sustainable energy storage applications.

Graphene oxide (GO)-derived materials have attracted significant attention as functional fillers for enhancing the barrier performance by polymer coatings. In this work, polyurethane (PU) composite coatings incorporating GO-derived material were systematically developed to investigate their effectiveness in suppressing n-heptane permeation. The effects of graphene type (GO, reduced GO_rGO, and functionalized GO_fGO), coating thickness, and fGO loading were systematically examined to elucidate the relationship between filler chemistry and diffusion behavior. The incorporation of GO-derived materials significantly reduced hydrocarbon permeation compared to pristine PU coatings, with PU-GO and PU-rGO composites showing reductions of approximately 21% and 18%, respectively. Notably, the PU-fGO composite exhibited the most pronounced improvement, achieving a 39% decrease in permeation rate. This improvement is attributed to enhanced interfacial compatibility and covalent interactions between fGO and the PU matrix, leading to uniform dispersion and highly tortuous diffusion pathways that effectively hinder hydrocarbon transport. These findings highlight the critical role of surface functionalization in optimizing filler-PU interactions. The fGO material demonstrates strong potential as an advanced filler in fuel barrier coatings for high-performance and environmentally friendly applications.

Graphene oxide (GO)-derived materials have attracted significant attention as functional fillers for enhancing the barrier performance by polymer coatings. In this work, polyurethane (PU) composite coatings incorporating GO-derived material were systematically developed to investigate their effectiveness in suppressing n-heptane permeation. The effects of graphene type (GO, reduced GO_rGO, and functionalized GO_fGO), coating thickness, and fGO loading were systematically examined to elucidate the relationship between filler chemistry and diffusion behavior. The incorporation of GO-derived materials significantly reduced hydrocarbon permeation compared to pristine PU coatings, with PU-GO and PU-rGO composites showing reductions of approximately 21% and 18%, respectively. Notably, the PU-fGO composite exhibited the most pronounced improvement, achieving a 39% decrease in permeation rate. This improvement is attributed to enhanced interfacial compatibility and covalent interactions between fGO and the PU matrix, leading to uniform dispersion and highly tortuous diffusion pathways that effectively hinder hydrocarbon transport. These findings highlight the critical role of surface functionalization in optimizing filler-PU interactions. The fGO material demonstrates strong potential as an advanced filler in fuel barrier coatings for high-performance and environmentally friendly applications.

The production of hydrogen (H2) from ammonia (NH3) cracking was studied using a rotating gliding arc plasma (rGAP), a promising green technology for direct H2 production. When sufficient electric power is applied, the H2 production from NH3 decomposition in rGAP occurs immediately at atmospheric conditions. However, the NH3 decomposition by rGAP strongly depends on key plasma parameters, including input power, initial NH3 concentration, and flow rate. Here, the effect of key inputs on the NH3 decomposition process was examined to determine the trends and evaluate their impact using standardized coefficients from linear models; the models are estimated and validated with experimental data. As a result, the trends and magnitude of the effects of the input parameters are visualized by floating bar diagrams of the standardized coefficients. This reveals that the initial NH3 concentration is the most critical factor, followed by the applied power and the total flow rate, for a high rate of H2 production and low energy consumption. The energy efficiency of the rGAP shows a significant improvement compared to other atmospheric pressure plasma sources; however, it is still lower than that of the thermal process under similar levels of specific energy input. Overall, the rGAP features NH3 conversion of up to 47% with energy consumption for H2 production around 0.65 MJ/mol H2. With the ability to quickly turn the process on/off by controlling the plasma power supply, the rGAP presents a potential method for fast and efficient H2 production from NH3.