RESUMO
Metal-organic frameworks (MOFs) based on tin (Sn) have shown great potential as materials for lithium storage, thanks to their ability to alleviate volume expansion due to the homogeneous distribution of Sn in a porous matrix framework. However, the weak mechanical strength of the porous Sn-MOF structure has been a major challenge, leading to pulverization during the discharging/charging process. To overcome this issue, we have developed a feasible strategy to strengthen the Sn-MOF mechanical properties by incorporating SiO2/GeO2 nanoparticles during the synthesis process. The resulting composites of Sn-Si and Sn-Ge exhibited high energy density and long-term cycle stability, thanks to their synergistic effect in alloying and conversion reactions. Our density functional theory (DFT) calculations have revealed that the rigid SiO2/GeO2 nanoparticles enhance the Sn-MOF mechanical properties, including Young's and shear moduli, which contribute to the long-term cycle stability of these composites.
RESUMO
The development of inexpensive non-precious metal materials as high-efficiency stable oxygen reduction reaction (ORR) catalysts holds significant promise for application in metal-air batteries. Here, we synthesized a series of nanohybrids formed from MnO nanoparticles anchored on N-doped Ketjenblack carbon (MnO/NC) via a facile hydrothermal reaction and pyrolysis strategy. We systematically investigated the influence of pyrolysis temperature (600 to 900 °C) on the ORR activities of the MnO/NC samples. At the optimized pyrolysis temperature of 900 °C, the resulting MnO/NC (referred to as MnO/NC-900) exhibited superior ORR activity (onset potential = 0.85 V; half-wave potential = 0.74 V), surpassing other MnO/NC samples and nitrogen-doped Ketjenblack carbon (NC). Additionally, MnO/NC-900 demonstrated better stability than the Pt/C catalyst. The enhanced ORR activity of MnO/NC-900 was attributed to the synergy effect between MnO and NC, abundant surface carbon defects and surface-active components (N species and oxygen vacancies). Notably, the Zinc-air battery (ZAB) equipped MnO/NC-900 as the cathode catalyst delivered promising performance metrics, including a high peak power density of 146.5 mW cm-2, a large specific capacity of 795 mA h gZn -1, and an excellent cyclability up to 360 cycles. These results underscore the potential of this nanohybrid for applications in energy storage devices.
RESUMO
OBJECTIVE: To explore the plasma metabolomic characteristics of children with transfusion-dependent thalassemia (TDT), and reveal the changes of metabolic pattern in children with TDT. METHODS: 23 children with TDT who received regular blood transfusion in Ganzhou Women and Children's Health Care Hospital in 2021 were selected, and 11 healthy children who underwent physical examination during the same period were selected as the control group. The routine indexes between children with TDT and the control group were compared, and then the metabolic composition of plasma samples from children with TDT and the control group was detected by liquid chromatography-mass spectrometry. An OPLS-DA model was established to perform differential analysis on the detected metabolites, and the differential metabolic pathways between the two groups were analyzed based on the differential metabolites. RESULTS: The results of routine testing showed that the indexes of ferritin, bilirubin, total bile acid, glucose and triglycerides in children with TDT were significantly higher than those in healthy controls, while hemoglobin and total cholesterol were significantly lower (all P <0.05). However there was no significant difference in lactate dehydrogenase between the two groups (P >0.05). Compared with the control group, 190 differential metabolites (VIP>1) were identified in TDT children. Among them, 168 compounds such as arginine, proline and glycocholic acid were significantly increased, while the other 22 compounds such as myristic acid, eleostearic acid, palmitic acid and linoleic acid were significantly decreased. The metabolic pathway analysis showed that the metabolic impact of TDT on children mainly focused on the upregulation of amino acid metabolism and downregulation of lipid metabolism. CONCLUSION: The amino acid and lipid metabolism in children with TDT were significantly changed compared with the healthy control group. This finding is helpful to optimize the treatment choice for children with TDT, and provides a new idea for clinical treatment.