Joo-Il Park

This review presents field-relevant criteria for selecting hydrolysis-based decontaminants for organophosphorus nerve-agent decontamination according to water and base availability.

Development of solid acid-catalysts that balance acid accessibility with structural integrity is of critical interest for efficient biodiesel production. Here, we report strategic engineering of a core-shell SiW(silicotungstic acid)@ZIF-8(Zeolitic Imidazolate Framework-8) platform (HZS) with systematically varied ratios to examine how the optimized architecture governs the acid environment, structural preservation and catalytic behavior on canola-oil (trans)esterification. In-depth microscopic analysis reveals well-defined core-shell features at an optimized ratio, where successful chemical anchoring of SiW via thermally robust W-O-N bonding is confirmed by advanced spectroscopic analyses, thereby facilitating electronic modulation. Crucially, the optimized HZS-2 composition reveals the largest concentration of strong acid-sites alongside high levels of total acidity, due to the well-distributed coexistence of Brønsted and Lewis acid pathways. Notably, HZS-2 achieves a remarkable space-time yield of 10.21 g·g_cat^-1·h^-1 with exceeding 95 % selectivity within a shortened 2-hour reaction time, with an interfacial synergy factor of 1.52. Variations in product mixtures are observed mainly within the dominant C18-rich ester fraction, indicating catalyst-dependent product distributions. Moreover, it maintains 100 % activity threshold for at least 5 consecutive cycles, while recovered catalyst retains its solid-state structure, showing competitive performance of the recently reported acid-catalysts. These results exhibit a favorable balance of accessible acid-site generation with stable porous framework, providing a robust platform that integrates multi-dimensional catalytic descriptors and actual productivity of high-quality biodiesel.

Development of solid acid-catalysts that balance acid accessibility with structural integrity is of interest for efficient biodiesel production. Here, we report strategic engineering of a core-shell ZIF-8@SiW platform (HZS) with different ratios to examine how the optimized architecture governs acid environment, structural preservation and catalytic behavior on canola-oil (trans)esterification. In-depth microscopic analysis reveals well-defined core-shell features at adjusted ratio where successful chemical anchoring of SiW via thermally robust W-O-N bonding is confirmed by advanced spectroscopic analyses of XPS and NEXAFS, thereby facilitating electronic modulation. We identify a loading-dependent structural evolution where higher SiW progressively disrupts the ZIF-8 framework, which shows a sharp decline in surface area and acidity. The intermediate loading (HZS-2) reveals the largest concentration of strong acid-sites even at high levels of total acidity, yielding FAME of 81.5% with over 95% selectivity within a shortened 2 hours under applied conditions. Moreover, variations in product mixtures are observed mainly within the dominant C18-rich ester fraction, indicating catalyst-dependent product distributions. Notably, a remarkable space-time yield of 10.21 gꞏgcat-1ꞏh-1 from a synergy factor of 1.52, which maintains 100% activity threshold for at least 5 cycles, while recovered catalyst retains its solid-state structure, comprehensively outperforming the conventional and recently reported acid-catalysts. These results exhibit a superior balance of accessible acid-site generation with stable porous framework, providing robust platform that integrates multi-dimensional catalytic descriptors and actual productivity of high-quality biodiesel.

Biodiesel, predominantly derived from canola oil, is recognized as an essential renewable and ecofriendly fuel, significantly reducing greenhouse gas emissions and fossil fuel dependency. Despite its advantages, optimizing catalytic reactions remains challenging. This research systematically evaluates the catalytic efficiency and selectivity of three homogeneous heteropoly acids (HPAs)phosphotungstic acid (PWA), phosphomolybdic acid (PMo), and silicotungstic acid (SiW)for biodiesel production using canola oil. Under the optimized homogeneous reaction conditions, the Brønsted acidity was quantitatively analyzed using UV–vis spectroscopy with 4-nitroaniline, while solvent-dependent dissociation characteristics were confirmed via FT-IR spectroscopy. Among the HPAs, PWA and PMo exhibited higher methanol solubility, correlating to significantly greater FAME yields (43.97% and 47.22%, respectively) compared with SiW (21.81%). Product analysis revealed that W-based catalysts (PWA, SiW) predominantly produced polyunsaturated esters such as C18:3 (65.9% and 67.5%, respectively), while PMo favored monounsaturated esters such as C18:1 (55.1%), reflecting intrinsic differences in acidity and catalyst configuration. Effective biphasic separation using dichloromethane and water facilitated catalyst recovery and product purification, with FT-IR confirming HPAs’ retention in the aqueous phase. This study underscores the necessity of concurrently managing catalyst solubility and acidity to optimize biodiesel production and product selectivity using homogeneous HPAs, in which the process of efficient phase separation is an advantage for effective management.

Drying characteristics of LGA crystals in this study: crystals with a smaller aspect ratio and larger crystal diameter exhibited lower mother liquor contents and faster drying times.

This study addresses the critical challenge of carbon corrosion in proton exchange membrane fuel cells (PEMFCs) by developing hybrid supports that combine the high surface area of carbon black (CB) with the superior crystallinity and graphitic structure of carbon nanofibers (CNFs). Two commercially available CB samples were physically activated and composited with two types of CNFs synthesized via chemical vapor deposition using different carbon sources. The structure, morphology, and crystallinity of the resulting CNF–CB hybrid supports were characterized, and the performances of these hybrid supports in mitigating carbon corrosion and enhancing the PEMFC performance was evaluated through full-cell testing in collaboration with a membrane electrode assembly (MEA) manufacturer (VinaTech, Seoul, Republic, of Korea), adhering to industry-standard fabrication and evaluation procedures. Accelerated stress tests following the US Department of Energy protocols revealed that incorporating CNFs enhanced the durability of the CB-based hybrid supports without compromising their performance. The improved performance of the MEAs with the hybrid carbon support is attributed to the ability of the CNF to act as a structural backbone, facilitate water removal, and provide abundant edge plane sites for anchoring the platinum catalyst, which promoted the oxygen reduction reaction and improved catalyst utilization. The findings of this study highlight the potential of CNF-reinforced CB supports for enhancing the durability and performance of PEMFCs.

The hydrodeoxygenation (HDO) of biomass pyrolysis oil (BPO) was evaluated in the presence of two commercial alumina-supported transition metal catalysts, NiMo/alumina-1 (NM1) and NiMo/alumina-2 (NM2). The study explored two characteristic aspects: how HDO reaction conditions affected the oxygen content, density, and boiling point distribution of BPO with varying temperature and HDO reaction time, and the roles of catalysts. Characterizations of HDO-treated oils included elemental analysis, GC-MS, SIMDIS, ¹³C NMR, and ¹H NMR, and characterizations of catalysts included NH₃-TPD, XRF, and TPO-MS analysis. The results show that both NM1 and NM2 catalysts removed oxygenated compounds effectively, which led to decreases in density and shifts toward higher boiling point distributions of BPO. Compared to the NM1 catalyst, NM2 had a higher acidity and enhanced HDO activity. The best HDO reaction performance was achieved in the presence of the NM2 catalyst at 300 °C. Furthermore, HDO reactions showed a significant amount of CO₂, CH₄, C₂H₆, and C₃H₈, which suggests that HDO reactions proceeded via a series of reactions of decarboxylation, water–gas shift, and methanation. In addition, hydrocarbon fraction tests suggested a favorable potential for the blending of HDO-treated biomass pyrolysis oil (HDO-BPO) with petroleum-derived fractions.