Hydrogen Adsorption on Manganese-Doped Carbon, Boron Nitride, and Silicon Carbide Nanocones: A Density Functional Theory Study

2026-04-03T12:19:15+00:00

The quest for efficient hydrogen storage media persists as a pivotal bottleneck in the transition toward large-scale hydrogen-based energy infrastructures. In the present study, systematic density functional theory (DFT) calculations were executed via the Gaussian 09 software package to scrutinize the hydrogen adsorption phenomena on pristine and manganese-doped nanocones (NCs) comprising
carbon (C), boron nitride (BN), and silicon carbide (SiC). By employing a rigorous computational framework, we evaluated the structural stability and electronic modulation of these nanostructures to determine their viability for storage applications. Our findings underscore the superiority of the Mn– Si41C34H9–M2 configuration characterized by a 300° disclination angle which demonstrated an
exceptionally robust interaction with molecular hydrogen. This specific system yielded a significant adsorption energy of -4.98 eV, accompanied by a pronounced dipole moment enhancement of 25.74 D, thereby indicating substantial surface polarization. Furthermore, the electronic landscape analysis revealed an ultra-narrow energy gap of 0.02 eV for the Mn-doped SiC nanocone, suggesting a highly reactive state that facilitates charge transfer processes. Natural Population Analysis (NPA) and molecular orbital insights indicate that Mn incorporation induces a localized electronic redistribution, creating potent catalytic sites for hydrogen binding. Comparative assessment confirms that Mn-doped SiC nanocones outperform their C and BN counterparts in terms of binding affinity, highlighting the indispensable role of transition-metal doping in fine-tuning the chemisorption characteristics. These results provide critical theoretical benchmarks for designing dopant-induced nanoscale platforms tailored for high-capacity hydrogen storage.

Optimization of Different Extraction Methods of irradiated Chamomile on Antioxidant Activity and Chamazulene Content Using Response Surface Methodology

2026-04-12T01:31:28+00:00

This study successfully determined the optimal supercritical fluid (CO2) extraction (SFE) parameters for recovering high-potency antioxidants from irradiated chamomile (Matricaria recutita L.). Utilizing a Box–Behnken response surface design, the effects of pressure, temperature, and extraction time were modeled to maximize radical-scavenging activity. Determinations of antioxidant activities of chamomile oil samples were accomplished using 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2´- azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods The optimization identified distinct coordinates for peak performance: 257.17 bar, 50°C, and 180 min for DPPH (IC50 = 162.15 μg/mL), and 272.72 bar, 50°C, and 131.51 min for ABTS (IC50 = 85.55 μg/mL). Validation trials confirmed the model's high predictive accuracy. While SFE-derived oils and powders exhibited robust antioxidant activity, they remained slightly below synthetic standards. Furthermore, Gas Chromatography / Mass Spectroscopy (GC/MS) analysis identified key bioactives - including α- bisabolol oxides, (E)-β-farnesene, and chamazulene - in accordance with European Pharmacopoeia standards, noting that maximum chamazulene recovery (7.12%) required a 4-hour steam distillation.

Current Science International

Hydrogen Adsorption on Manganese-Doped Carbon, Boron Nitride, and Silicon Carbide Nanocones: A Density Functional Theory Study

Optimization of Different Extraction Methods of irradiated Chamomile on Antioxidant Activity and Chamazulene Content Using Response Surface Methodology