Dehydration Achieving the Iron Spin State Regulation of Prussian Blue for Boosted Sodium-Ion Storage Performance.

Prussian blue analogs (PBAs) show promise as cathodes for sodium-ion batteries due to their notable cycle stability, cost-effectiveness, and eco-friendly nature, yet the presence of interstitial water limits the specific capacity and obstructs Na+ mobility within the material. Although considerable experimental efforts are focused on dehydrating water for capacity enhancement, there is still a deficiency of a comprehensive understanding of the low capacity of low-spin Fe resulting from interstitial water, which holds significance in Na+ storage. This study introduces a novel gas-assisted heat treatment method to efficiently remove interstitial water from Fe-based PBA (NaFeHCF) electrodes and combines experiments and theoretical calculations to reveal the iron spin state regulation that is related to the capacity enhancement mechanism. This dehydration strategy significantly enhances battery capacity, especially the portion at higher voltages (3.4-4.0 V). The increase in capacity is attributed to the following factors: an enhanced proportion of Fe2+, reduced water content which facilitates faster charge transfer, and the activation of low spin Fe2+. The optimized NaFeHCF demonstrated impressive half-cell performance of retaining 87.3% capacity after 2000 cycles at a 5 C rate and achieving 100 mAh g-1 capacity over 200 cycles when being paired with hard carbon, exhibiting its practical potential.

MOF-Derived CeO2 Nanorod as a Separator Coating Enabling Enhanced Performance for Lithium-Sulfur Batteries.

The deployment of Li-S batteries in the commercial sector faces obstacles due to their low electrical conductivity, slow redox reactions, quick fading of capacity, and reduced coulombic efficiency. These issues stem from the "shuttle effect" associated with lithium polysulfides (LiPSs). In this work, a haystack-like CeO2 derived from a cerium-based metal-organic framework (Ce-MOF) is obtained for the modification of a polypropylene separator. The carbon framework and CeO2 coexist in this haystack-like structure and contribute to a synergistic effect on the restriction of LiPSs shuttling. The carbon network enhances electron transfer in the conversion of LiPSs, improving the rate performance of the battery. Moreover, CeO2 enhances the redox kinetics of LiPSs, effectively reducing the "shuttle effect" in Li-S batteries. The Li-S battery with the optimized CeO2 modified separator shows an initial discharge capacity of 870.7 mAh/g at 2 C, maintaining excellent capacity over 500 cycles. This research offers insights into designing functional separators to mitigate the "shuttle effect" in Li-S batteries.

Facile hydrothermal synthesis of rod-like Nb2O5/Nb2CTx composites for visible-light driven photocatalytic degradation of organic pollutants.

The MXene-based transition metal oxide composite is a potential candidate for photocatalysts. Rod-like pseudohexagonal phase Nb2O5/Nb2CTx composites were synthesized by a simple hydrothermal oxidation of 2D layered Nb2CTx. The Nb2O5/Nb2CTx composites show superior photocatalytic activity for 98.5% of degradation of Rhodamine B (RhB) for 120 min and 91.2% of tetracycline hydrochloride (TC-HCl) for 180 min under visible light irradiation. The Schottky junction is formed between Nb2O5 nanorods and Nb2CTx and the photo-generated carriers are effectively separated, enhancing the photocatalytic activity of the Nb2O5/Nb2CTx. High photoactivity and cycle stability of Nb2O5/Nb2CTx composites indicate that hydrothermal oxidation of 2D layered Nb2CTx is an alternative to prepare efficient photocatalyst for degradation of organic pollutants.

Rapid microwave-assisted bio-synthesized silver/Dandelion catalyst with superior catalytic performance for dyes degradation.

Silver nanoparticles were synthesized under microwave irradiation, a facile and efficient way, using dandelion extract as reducing and capping agents. The as-synthesized silver nanoparticles/Dandelion compounds (AgNPs/Dandelion) were characterized by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), Zeta potential and ultraviolet visible (UV-vis) spectroscopy. The catalytic degradation activity of AgNPs/Dandelion for Methyl orange (MO) and Rhodamine B (RhB) in the presence of NaBH4 were recorded by UV-vis spectroscopy. AgNPs/Dandelion exhibit excellent catalytic degradation activity for RhB and MO with rate constants of 0.1038 s-1 and 0.0393 s-1, respectively.