Ion insertions always involve electrode-electrolyte interface process, desolvation for instance, which determines the electrochemical kinetics. However, it′s still a challenge to achieve fast ion insertion and invest...
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Ion insertions always involve electrode-electrolyte interface process, desolvation for instance, which determines the electrochemical kinetics. However, it′s still a challenge to achieve fast ion insertion and investigate ion transformation at interface. Herein, the interface deprotonation of NH 4 + and the introduced dissociation of H 2 O molecules to provide sufficient H 3 O + to insert into materials′ structure for fast energy storages are revealed. Lewis acidic ion-NH 4 + can, on one hand provide H 3 O + itself via deprotonation, and on the other hand hydrolyze with H 2 O molecules to produce H 3 O + . In situ attenuated total reflection-Fourier transform infrared ray method probed the interface accumulation and deprotonation of NH 4 + , and density functional theory calculations manifested that NH 4 + tend to thermodynamically adsorb on the surface of monoclinic VO 2 , and deprotonate to provide H 3 O + . In addition, the inserted NH 4 + has a positive effect for stabilizing the VO 2 (B) structure. Therefore, high specific capacity (>300 mAh g −1 ) and fast ionic insertion/extraction (<20 s) can be realized in VO 2 (B) anode. This interface derivation proposes a new path for designing proton ion insertion/extraction in mild electrolyte.
In this study, a novel fibrous chitosan biosorbent was prepared using LiOH/KOH/urea/HO (4.5:7:8:80.5 by weight) as spinning solvent. The fibrous chitosan exhibited a higher adsorption capacity and a faster adsorption ...
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In this study, a novel fibrous chitosan biosorbent was prepared using LiOH/KOH/urea/HO (4.5:7:8:80.5 by weight) as spinning solvent. The fibrous chitosan exhibited a higher adsorption capacity and a faster adsorption rate for Co and Sr, compared with spherical chitosan due to its high specific surface area (16.9 m g), uniform fineness (24.1 μm), and good mechanical strength. The adsorption capacity of fibrous chitosan for Co and Sr was 31.3 mg g and 20.0 mg g, respectively, which was higher than that of spherical chitosan (22.5 mg gfor Co and 8.9 mg g for Sr). The coordination between -NH/-OH of chitosan and the nuclide ions was the rate-limiting step. The improvement of adsorption performance was due to the higher specific surface area which increased the exposure degree of functional groups (adsorptive sites). This new wet-spun fibrous chitosan biosorbent showed great potential in the adsorptive removal of nuclides ions from aqueous solution.
Hierarchical structures are ubiquitous in both animals and plants. The coordination of the hierarchical structures and functions makes living organisms function efficiently. This explains why hierarchical metal oxide ...
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Hierarchical structures are ubiquitous in both animals and plants. The coordination of the hierarchical structures and functions makes living organisms function efficiently. This explains why hierarchical metal oxide (HMO)-based micro/nanostructures have recently received huge attention as anodes for application in highly efficient lithium-ion batteries (LIBs). Indeed, hierarchy in such micro/nanostructured HMOs offers high specific surface area, stable structure, short path length, and improved higher packing density to improve the reaction kinetics and Li + /e − transport kinetics, resulting in highly enhanced rate capability and cycling stability for LIBs. This report focuses on the hierarchical design from structural, morphological, porous, and component levels to engineer the HMOs as anodes for LIBs. The advantages of micro/nanostructured HMO-based on three reaction mechanisms (intercalation/deintercalation, conversion, and alloying/dealloying), important challenges ahead, and future perspectives on designing advanced electrode materials for next-generation high-performance LIBs are discussed.
Piezocatalysis, converting mechanical vibration into chemical energy, has emerged as a promising candidate for water‐splitting technology. However, the efficiency of the hydrogen production is quite limited. We herei...
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Piezocatalysis, converting mechanical vibration into chemical energy, has emerged as a promising candidate for water‐splitting technology. However, the efficiency of the hydrogen production is quite limited. We herein report well‐defined 10 nm BaTiO 3 nanoparticles (NPs) characterized by a large electro‐mechanical coefficient which induces a high piezoelectric effect. Atomic‐resolution high angle annular dark field scanning transmission electron microscopy (HAADF‐STEM) and scanning probe microscopy (SPM) suggests that piezoelectric BaTiO 3 NPs display a coexistence of multiple phases with low energy barriers and polarization anisotropy which results in a high electro‐mechanical coefficient. Landau free energy modeling also confirms that the greatly reduced polarization anisotropy facilitates polarization rotation. Employing the high piezoelectric properties of BaTiO 3 NPs, we demonstrate an overall water‐splitting process with the highest hydrogen production efficiency hitherto reported, with a H 2 production rate of 655 μmol g −1 h −1 , which could rival excellent photocatalysis system. This study highlights the potential of piezoelectric catalysis for overall water splitting.
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