118 research outputs found
Extent of Pseudocapacitance in HighâSurface Area Vanadium Nitrides
Early transitionâmetal nitrides, especially vanadium nitride (VN), have shown promise for use in high energy density supercapacitors due to their high electronic conductivity, areal specific capacitance, and ability to be synthesized in high surface area form. Their further development would benefit from an understanding of their pseudocapacitive charge storage mechanism. In this paper, the extent of pseudocapacitance exhibited by vanadium nitride in aqueous electrolytes was investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The pseudocapacitance contribution to the total capacitance in the nitride material was much higher than the doubleâlayer capacitance and ranged from 85â% in basic electrolyte to 87â% in acidic electrolyte. The mole of electrons transferred per VN material during pseudocapacitive charge storage was also evaluated. This pseudocapacitive chargeâstorage is the key component in the full utilization of the properties of earlyâtransition metal nitrides for highâenergy density supercapacitors.Doubleâlayer capacitance vs. pseudocapacitance: the electrostatic doubleâlayer and pseudocapacitive charge storage mechanisms in highâsurfaceâarea vanadium nitride are investigated. The magnitude of the pseudocapacitive charge storage capacity and mole of electrons transferred are reported. The pseudocapacitive chargeâstorage mechanism is the key component in maximizing the energy density of supercapacitors based on transitionâmetal nitrides.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146597/1/batt201800050.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146597/2/batt201800050_am.pd
X-ray radio-enhancement by TiCT MXenes in soft tissue sarcoma
Radiotherapy is a cornerstone of cancer treatment. However, due to the low tissue specificity of ionizing radiation, damage to the surrounding healthy tissue of the tumor remains a significant challenge. In recent years, radio-enhancers based on inorganic nanomaterials have gained considerable interest. Beyond the widely explored metal and metal oxide nanoparticles, 2D materials, such as MXenes, could present potential benefits because of their inherently large specific surface area. In this study, we highlight the promising radio-enhancement properties of TiCT MXenes. We demonstrate that atomically thin layers of titanium carbides (TiCT MXenes) are efficiently internalized and well-tolerated by mammalian cells. Contrary to MXenes suspended in aqueous buffers, which fully oxidize within days, yielding rice-grain shaped rutile nanoparticles, the MXenes internalized by cells oxidize at a slower rate. This is consistent with cell-free experiments that have shown slower oxidation rates in cell media and lysosomal buffers compared to dispersants without antioxidants. Importantly, the MXenes exhibit robust radio-enhancement properties, with dose enhancement factors reaching up to 2.5 in human soft tissue sarcoma cells, while showing no toxicity to healthy human fibroblasts. When compared to oxidized MXenes and commercial titanium dioxide nanoparticles, the intact 2D titanium carbide flakes display superior radio-enhancement properties. In summary, our findings offer evidence for the potent radio-enhancement capabilities of TiCT MXenes, marking them as a promising candidate for enhancing radiotherapy
Review of MXenes as new nanomaterials for energy storage/delivery and selected environmental applications
X-ray radio-enhancement by TiâCâTâ MXenes in soft tissue sarcoma
Radiotherapy is a cornerstone of cancer treatment. However, due to the low tissue specificity of ionizing radiation, damage to the surrounding healthy tissue of the tumor remains a significant challenge. In recent years, radio-enhancers based on inorganic nanomaterials have gained considerable interest. Beyond the widely explored metal and metal oxide nanoparticles, 2D materials, such as MXenes, could present potential benefits because of their inherently large specific surface area. In this study, we highlight the promising radio-enhancement properties of TiâCâTâ MXenes. We demonstrate that atomically thin layers of titanium carbides (TiâCâTâ MXenes) are efficiently internalized and well-tolerated by mammalian cells. Contrary to MXenes suspended in aqueous buffers, which fully oxidize within days, yielding rice-grain shaped rutile nanoparticles, the MXenes internalized by cells oxidize at a slower rate. This is consistent with cell-free experiments that have shown slower oxidation rates in cell media and lysosomal buffers compared to dispersants without antioxidants. Importantly, the MXenes exhibit robust radio-enhancement properties, with dose enhancement factors reaching up to 2.5 in human soft tissue sarcoma cells, while showing no toxicity to healthy human fibroblasts. When compared to oxidized MXenes and commercial titanium dioxide nanoparticles, the intact 2D titanium carbide flakes display superior radio-enhancement properties. In summary, our findings offer evidence for the potent radio-enhancement capabilities of TiâCâTâ MXenes, marking them as a promising candidate for enhancing radiotherapy.ISSN:2047-4830ISSN:2047-484
Development of asymmetric supercapacitors with titanium carbide-reduced graphene oxide couples as electrodes
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