The annual global output of denim exceeds a staggering 9 billion meters, valued at over $25 billion. The conventional production relies on sodium dithionite for indigo dye reduction, a costly process that also generates environmentally harmful wastewater with sulfite and sulfate ions. Addressing these issues, we present an eco-friendly, cost-effective electrochemical reduction approach using a novel molybdenum disulfide (MoS2) molecule–proton dual adsorption system for the electrocatalytic hydrogenation (ECH) of indigo dye. This system facilitates a phase shift from 2H to 1T in MoS2 by intercalating organic amine cations, enhancing the coadsorption of active hydrogen and indigo molecules, thereby boosting the ECH activity. The dimethylamine-cation intercalated MoS2 electrode material (MoS2-DMA-CF) achieves over 95% dye reduction efficiency and more than 75% faradaic efficiency in ECH, surpassing traditional methods with a 25% increase in K/S value, improved color fastness, and less than 5% color variation after 10 cycles. Additionally, this method reduces energy consumption by 92.424% and dyeing costs by 90.416%, with the dyeing wastewater exhibiting excellent biodegradability, offering substantial environmental benefits. This innovative approach not only yields significant cost savings but is also highly scalable, providing a sustainable solution for denim fabrication.
To meticulously establish an efficient photothermal multifunctional hydrogel dressing is a prospective strategy for the treatment of diabetic chronic wounds.
Heat insulation materials are materials that have the ability to insulate heat and impede the transfer of heat flow and are usually characterized by light weight, looseness, high porosity, and low thermal conductivity. Therefore, they are widely used in industries such as thermal equipment and pipeline, construction, aerospace, and other fields. Electrospun nanofibers possess a high specific surface area and controllable pore structure and are often used as heat insulation materials. Furthermore, aerogel refers to a gel composed of microporous solids in which the gas is the dispersed phase and the nanofiber aerogel can be synthesized from nanofibrous membranes. More importantly, the high specific surface area and high thermal stability of nanofibers make the prepared ceramic aerogels more stable at high temperatures. In this chapter, the heat insulation mechanism and conductivity of high-temperature heat insulation materials are described. The high-temperature insulation material is mainly divided into two-dimensional (2D) nanofibrous membrane and 3D nanofiber-based aerogel according to the structure. The research status of 2D electrospun nanofibrous membrane, 3D electrospun nanofiber-based aerogel insulation materials, and application of electrospun nanofiber-based insulation materials is emphatically introduced, and the development of high-temperature insulation materials is prospected.
Abstract The rational design of carbon‐supported transition metal single‐atom catalysts necessitates precise atomic positioning within the precursor. However, structural collapse during pyrolysis can occlude single atoms, posing significant challenges in controlling both their utilization and coordination environment. Herein, we present a surface atom adsorption‐flash heating (FH) strategy, which ensures that the pre‐designed carbon nanofiber structure remains intact during heating, preventing unforeseen collapse effects and enabling the formation of metal atoms in nano‐environments with either tetra‐nitrogen or penta‐nitrogen coordination at different flash heating temperatures. Theoretical calculations and in situ Raman spectroscopy reveal that penta‐nitrogen coordinated cobalt atoms (Co‐N 5 ) promote a lower energy pathway for oxygen reduction and oxygen evolution reactions compared to the commonly formed Co‐N 4 sites. This strategy ensures that Co‐N 5 sites are fully exposed on the surface, achieving exceptionally high atomic utilization. The turnover frequency (65.33 s −1 ) is 47.4 times higher than that of 20 % Pt/C under alkaline conditions. The porous, flexible carbon nanofibers significantly enhance zinc‐air battery performance, with a high peak power density (273.8 mW cm −2 ), large specific capacity (784.2 mAh g −1 ), and long‐term cycling stability over 600 h. Additionally, the flexible fiber‐shaped zinc‐air battery can power wearable devices, demonstrating significant potential in flexible electronics applications.
In electrospinning, the addition of salts results in a higher charge density on the surface of jet. The theoretical analysis shows that the relationship between radius r of jet and the axial distance z from nozzle follows an allometric law in the form r ~ z -0.5 in case of full surface charge, and the scaling exponent becomes larger when the jet has part surface charge. Theoretical analysis also showed that the electricity potential with high content of LiCl descends more sharply than low content LiCl during the charged fibers moving. LiCl was chosen to confirm the theory. The experimental data agreed very well with our theoretical analysis by a series of experiments. Moreover, the structures of nanofibers with LiCl were investigated.
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