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Persistent zinc-ion storage in mass-produced V2O5 architecture
No full textRechargeable zinc-ion batteries (ZIBs) appear to be a promising candidate for large-scale energy storage system because of the abundance and inherent safety of the zinc negative electrode. Despite these benefits, huge polarization caused by the intercalation of multivalent charge carrier Zn2+ into the cathodic hosts remains a long-standing challenge impeding the development of high-performance ZIBs. Herein, we demonstrate the viability of the V2O5 nanorods constructed 3D porous architectures (3D-NRAs-V2O5 ) as cathode for ZIBs. Notably, the 3D-NRAs-V2O5 can be scaled up to kilo-gram production based on a simple sol-gel reaction followed by an annealing process. The synergic contributions from the 3D porous framework and layered structures of the 3D-NRAs-V2O5 lead a more facile Zn2+ ions (de)intercalation storage process. Consequently, it offers high reversible capacity of 336 mAh g at a high current density of 50 mA g(-1) and exhibits excellent long-term cyclic stability with a capacity retention of 85% over 5000 cycles at a high current density of 10 A g(-1). Furthermore, the use of various ex-situ characterization techniques and first-principles calculations has successfully unravelled the Zn(2+)ions storage mechanism of the 3D-NRAs-V2O5 Besides the excellent electrochemical performance of the 3D-NRAs-V2O5, it can also be easily scaled up based on the simple synthetic protocol, which shows great potential to be practically used for the next-generation large-scale energy storage applications
Family of Highly Luminescent Pure Ionic Copper(I) Bromide Based Hybrid Materials
No full textWhile a number of highly luminescent copper-(I) halide based hybrid materials built on coordinate bonds (Cu-L; L = N, P, S-based ligands) have been obtained, the poor structural stability largely limited their commercialization. In contrast, according to the previous studies, the ionic structures (L-free) are more stable than those built on Cu-L coordinate bonds. However, the extremely weak emission hinders their optical applications. Herein, we report a tetra-alkylammonium-cation-induced strategy for the synthesis of stable and highly luminescent ionic CuBr-based hybrid materials. It is interesting to find that the tetra-alkylammonium cations with different chains could induce diverse CuBr-based anions. Moreover, most of these CuBr-based hybrids are highly luminescent, which makes them promising candidates as an alternative to phosphors and with potential applications in sensing
Infrared Photodissociation Spectroscopic and Theoretical Study of [Co(CO2)(n)](+) Clusters
No full textThe mass-selected infrared photodissociation (IRPD) spectroscopy was utilized to investigate the interactions of cationic cobalt with carbon dioxide molecules. Quantum chemical calculations were performed on the [Co(CO2)(n)](+) clusters to identify the structures of the low-lying isomers and to assign the observed spectral features. All the [Co(CO2)(n)](+) (n=2-6) clusters studied here show resonances near the CO2 asymmetric stretch of free CO2 molecule. Experimental and calculated results indicate that the CO2 molecules are weakly bound to the Co+ cations in an end-on configuration via a charge-quadrupole electrostatic interaction. The present IRPD spectra of [Co(CO2)(n)](+) clusters have been compared to those of Ar-tagged species ([Co(CO2)(n)](+)-Ar), which would provide insights into the tagging effect of rare gas on the weakly-bounded clusters
Tungsten-based catalysts for lignin depolymerization: the role of tungsten species in C-O bond cleavage
No full textTungsten carbide has shown promising activity in lignin depolymerization, but the active site remains unclear yet due to its complicated surface tungsten species. Tungsten-based catalysts with designed species were therefore synthesized for hydrocracking beta-O-4 model compounds and lignin. X-ray diffraction, Raman spectroscopy, physical adsorption, X-ray photoelectron spectroscopy, and transmission electron microscopy as well as the temperature-programmed desorption of ammonia and H-2 microcalorimetric adsorption characterizations were employed to identify and quantify the composition of the as-prepared catalysts. It was found that the catalyst prepared under a N-2 atmosphere at 500 degrees C (N-2-500) had a major tungsten trioxide (WO3) phase and possessed dominantly acidic sites, while poor in terms of metallic sites. With the increasing treatment temperature, there was a clear evolution of the tungsten species from WO3 to W, and then to W2C and WC, along with an increase in metallic sites. As a result, the catalyst treated under 1000 degrees C (N-2-1000) exhibited a proper amount of both acidic sites and metallic sites. The structure-function relationship of the above catalysts was studied for transforming beta-O-4 model compounds and real lignin. In the model compounds reactions, N-2-500 showed poor conversion due to the lack of tungsten carbide species, while N-2-1000 exhibited both dehydration and hydrogenolysis activity due to the existence of balanced tungsten trioxide and tungsten carbide species, and therefore provided much higher yields of beta-O-4 cleavage products. The conversion results of beech dioxasolv lignin fitted well with the model compounds studied. The present work provides a deeper understanding of the role of different tungsten species in lignin depolymerization and makes an important contribution to the chemistry of tungsten-based catalysts in biomass conversion