Co0.8Zn0.2MoO4/C Nanosheet Composite: Rational Construction via a One-Stone-Three-Birds Strategy and Superior Lithium Storage Performances for Lithium-Ion Batteries

Magnetic chitosan-functionalized bone char for efficient removal of anionic dyes: Insights into adsorption-enhanced mechanism

Dyes are persistent organic pollutants that can bioaccumulate and present serious environmental challenges. The study fabricates a new adsorbent, magnetic chitosan-functionalized bone char (CsFeBC), co-doped with chitosan (Cs), Fe3O4, and bone char (BC) to enhance the removal of anionic dyes (Sunset Yellow [SY] and Reactive Blue 19 [RB19]). One-factor experiments showed that CsFeBC exhibits excellent adsorption capacity and a considerably higher removal efficiency. Remarkably, for SY, the removal efficiency of CsFeBC increased by 223.03 % compared to BC. Although the BET-specific surface area and ash content of CsFeBC are smaller than BC, it has a higher acidic oxygen-containing functional group content and electrical conductivity. Therefore, CsFeBC adsorption performance improves mainly due to strong electrostatic attractions. In addition, hydrogen bonding, ionic bonding, and esterification reactions occur between the hydroxyl (-OH) and amino (-NH2) functional groups introduced by Cs in CsFeBC and the sulfonic acid groups (-SO3-) in SY and RB19. Furthermore, CsFeBC performs effectively in a competitive environment where SY and RB19 coexist. Overall, CsFeBC demonstrates the potential of being an effective adsorbent for removing anionic dyes, providing a promising solution for reducing environmental pollution caused by ionic organic compounds.

Cooperative Cationic and Anionic Redox Reactions in Ultrathin Polyvalent Metal Selenide Nanoribbons for High-Performance Electrochemical Magnesium-Ion Storage

Rechargeable magnesium batteries (RMBs) are considered as potential energy storage devices due to their high volumetric specific capacity, good safety, as well as source abundance. Despite extensive efforts devoted to constructing an efficient magnesium battery system, the sluggish Mg²⁺ diffusion in conventional cathode materials often leads to slow rate kinetics, low capacity, and poor cycling lifespan. Although transition metal selenides with soft anion frameworks have attracted extensive attention, their Mg²⁺ storage mechanism still needs to be clarified. Herein, we demonstrate that the ultrathin CoSe₂ nanoribbons can be used as a robust cathode material for RMBs and reveal a novel Mg²⁺ storage mechanism based on cooperative cationic (Co) and anionic (Se) redox processes via systematic ex-situ characterizations. Compared to other metal selenide cathodes based on conversion reactions of solely metal cations, the cooperative cationic-anionic redox reactions of the CoSe₂ cathode contribute to obtaining an enhanced specific capacity and boosted electrochemical kinetics. Moreover, on one hand, the ultrathin nanoribbon structure enables effective contact between the electrode material and electrolyte and on the other hand significantly reduces the length and time consumption of Mg²⁺ diffusion, leading to dominated surface-driven capacitance-controlled Mg²⁺ storage behavior and rapid Mg²⁺ storage kinetics. As a result, the ultrathin CoSe₂ nanoribbon cathode exhibits a reversible discharge capacity of ∼130 mAh g^-1 at 100 mA g^-1, good rate capability (116 mAh g^-1 at 300 mA g^-1), and long cyclability over 600 cycles. This finding confirms the development potentiality of polyvalent metal selenide cathode materials based on a cooperative cationic-anionic redox mechanism for the construction of next-generation multivalent secondary batteries.

Study on clogging mechanisms of constructed wetlands from the perspective of wastewater electrical conductivity change under different substrate conditions

Constructed wetland (CW) has obvious advantages in wastewater treatment of medium and small towns. However, there is a lack of health monitoring research on CW system clogging. The electrical conductivity (EC) of wastewater purified by CW is related to the concentration of pollutants, which can reflect the CW clogging. The objectives of this study are to reveal the mechanisms of CWs substrate clogging from the perspective of wastewater EC changes, and provide an important reference for the health evaluation of CWs. The EC changes of nine CWs substrates (quartz sand, zeolite, gravel, coarse sand, straw biochar, sludge biochar, clay ceramsite, fly ash ceramsite and shale ceramsite) under different conditions (purified water, wastewater and wastewater + NaCl) were tested, and comparative analysis was used to reveal the influence of different substrate materials on the change of wastewater EC. The results show that the adsorption ability of substrate material isn't the main factor affecting the EC of wastewater, and the soluble component in the material is the important factor to cause the difference of EC increment. Under the condition of 0.4-1.0 g L^-1 NaCl concentration, the adsorption of substrate materials had little effect on the EC of wastewater, and the effect of NaCl used in CW tracer experiment was good. Quartz sand, coarse sand, gravel and sludge biochar have little influence on the change of wastewater EC. Other materials that have great influence on the change of wastewater EC can be treated by modifying or controlling the mixing ratio. The results are of great significance to reveal the clogging state of CW system and to carry out health assessment research.

Metal–organic framework-engaged synthesis of core–shell MoO2/ZnSe@N-C nanorods as anodes in high-performance lithium-ion batteries

A MoO₂/ZnSe@N-C nanorod was prepared through novel carbonization and selenization methods, shedding light on the design and application of metal selenides.

Electrospinning synthesis of amorphous NiMoO4/graphene dendritic nanofibers as excellent anodes for sodium ion batteries

Metal molybdates have attracted considerable attention as promising anode materials for sodium ion batteries (SIBs) due to their high theoretical specific capacity and excellent electrochemical performance. However, their low rate capacity and rapid capacity attenuation hinder their application in SIBs. Here, amorphous NiMoO₄/graphene nanofibers were prepared via an electrospinning method. The electrochemical performance of NiMoO₄ was first reported as the anode for SIBs. Amazingly, the amorphous NiMoO₄/graphene delivered an outstanding specific capacity of 260 mAh g^-1 after 100 cycles at 100 mA g^-1 at a potential range from 0.01-2.7 V and an excellent rate performance of 160 mAh g^-1 at 1 A g^-1. The superior electrochemical properties of amorphous NiMoO₄ can be ascribed to its amorphous structure and reduced diffusion distance, and the strong synergy of NiMoO₄ and graphene.