Lan Nguyen

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.

Hydrogen (H2) production from ammonia (NH3) decomposition is gaining interest as a promising green energy source, owing to its high hydrogen storage density and COx-free nature. However, extracting hydrogen through the NH3 decomposition reaction requires high temperatures to achieve high efficiency via catalytic processes. A combination of Ruthenium (Ru) with Ceria (Ce) as a catalyst is an efficient approach for low-temperature NH3 decomposition. Here, a Ru-Ce/γ-Al2O3 catalyst was prepared by the plasma method, incorporating incipient wetness impregnation with non-thermal plasma. For comparison purposes, the Ru-Ce/γ-Al2O3 catalyst was also prepared using conventional incipient wetness impregnation. The results indicated that the Ru-Ce/Al2O3 catalyst prepared by the plasma method improved the catalytic performance for NH3 decomposition. Specifically, pure ammonia gas was completely decomposed at 520 °C (WHSV = 5,000 mL.gcat-1 .h-1) while the conventional catalyst required 540 °C. At the same operating temperature, ranging from 350 to 500 °C, the NH3 conversion achieved by the plasma catalyst preparation was higher than that of the traditional method by at least 12%. During catalyst preparation, the catalyst undergoes significant changes due to interactions between its surface and the plasma, thereby improving its performance. To elucidate these changes, the catalysts were analyzed by TEM to determine the underlying mechanisms.

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.

This work investigates novel improvements in FeNi‐layered double hydroxide (LDH)/MIL‐88A heterocomposite for sustainable seawater electrolysis through a single‐step dual functionalization process. The Fe/Ni precursor weight ratio is optimized, resulting in the formation of smaller LDH petals and nano‐sized MIL‐88A metal–organic framework, which transforms into clusters of Fe₂O₃ nanospheres within a nitrogen‐functionalized carbon matrix over NiFe₂O₄ nano petals upon calcination. Furthermore, oxygen vacancies, and nitrogen functionalization are attained in a single step by employing thermal ammonia reduction, significantly improving the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activities. Particularly the oxygen vacancy and nitrogen functionalization are found to accelerate the O─O coupling step in OER by lowering the activation barrier. Likewise, the dual functionalization promotes destabilizing the hydride intermediates in HER potentially facilitating faster proton‐coupled electron transfer. Hence, the optimized electrode achieves current densities of 200 mA cm⁻² at overpotentials of 350 and 240 mV for OER and HER respectively. The chronopotentiometry stability tests confirms the electrode's durability over 200 h at 20 mA cm⁻² in alkaline seawater electrolyte. The optimized electrode, composed of cost‐effective and environmentally friendly materials, demonstrates robustness in alkaline seawater electrolytes, positioning it as a strong candidate for practical and sustainable water electrolysis applications.