Owing to their high theoretical energy density and carbon-free operation, Direct Ammonia Fuel Cells (DAFCs) have recently garnered substantial interest in the research community. However, the sluggish kinetics of the Ammonia Oxidation Reaction (AOR) significantly limit the practical applications of DAFCs. The ternary alloy catalyst PtIrZn has become a research focus due to its excellent electrocatalytic performance. However, designing PtIrZn nanocubes with high (100)-facet exposure to maximize AOR performance remains a major challenge. In this study, high (100)-facet-exposed PtIrZn nanocubes were successfully synthesized using a hydrothermal method, employing oleylamine as a reducing agent and dibenzyl ether as a morphology-directing agent. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) characterization confirmed their cubic structure and high proportion of (100) facets. Electrochemical testing indicated that PtIrZn nanocubes exhibited a significant current density (163.94 A g-1PtIr) in AOR, outperforming previously reported PtIrZn catalysts. Density Functional Theory (DFT) calculations further revealed that the (100) facets in the as-designed PtIrZn possess a lower reaction energy barrier and a more negative d-band center compared to the (111) facets. This leads to an enhanced dehydrogenation capacity of NH₃ and consequently accelerates the rate of AOR.
Chromatographic fractionation of the EtOH extracts of the marine-derived fungusAspergillusversicolorA18 has led to the isolation of 11 homo/hetero-dimers of aromatic bisabolane sesquiterpenoids including eight diphenyl ether-coupled aromatic bisabolanes (1a/1band5–10) and three homodimers (2–4), together with their monomers including three aromatic bisabolanes (11–13) and two diphenyl ethers (14and15). Their structures and absolute configurations were elucidated by extensive spectroscopic analysis including HRESIMS, 1D/2D NMR, calculated ECD, and the optical rotatory data. Among the four new compounds, (+/−)-asperbisabol A (1a/1b), asperbisabol B (2), and asperbisabol C (3), the enantiomers1aand1brepresent an unprecedented skeleton of diphenyl ether-coupled aromatic bisabolane sesquiterpenoids with a spiroketal core moiety. The neuroprotective effects of selected compounds against sodium nitroprusside (SNP)-induced injury were evaluated in PC12 cells by the MTT assay. Five compounds (1a,6, and8–10) showed remarkable neuroprotective activities at 10 μM, being more active than the positive control edaravone.Keywords:diphenyl ether-coupled aromatic bisabolane;aromatic bisabolane dimer;marine-derived fungus;Aspergillus versicolor;neuroprotective activity
Aryl ethers greatly influence lignin depolymerization and the oxygen content in lignin products. Cleaving aryl ethers normally requires harsh conditions such as high-pressure hydrogen gas and elevated temperature. Herein, we developed a synergistic method that combines photocatalytic hydrogen transfer with acid catalysis for H2-free hydrogenolysis of diphenyl ether and aromatic oxygenates at room temperature. The electron-enriched Pt/TiO2 surface stored abundant hydrogen species under light irradiation and efficiently catalyzed hydrogen transfer from isopropanol to aryl ethers. The acid mediated the hydrogenation sequence into: hydrogenolysis of aryl C–O bonds > saturation of aryl rings ≫ hydrogenolysis of aliphatic C–O bonds. DFT calculations suggested the aryl ether bond adsorbed on the Pt surface was weakened through protonation. This method delivered 98% yield of aliphatic monomers (73% cyclohexane and 25% cyclohexanol) from cleavage of diphenyl ether, and converted aromatic mixtures into cycloalkanes (57%) and aliphatic alcohols (9%) under mild conditions.
危险品化学品经营许可证（带存储）