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The polysulfide shuttle mechanism and insulating characteristics of sulfur and discharge products are the two major drawbacks of Li−S batteries. These increase internal cell resistances, resulting in low battery performance and life. In this study, we investigate the effect of cathode material on the cell resistances by preparing two different cathodes: by encapsulating sulfur (S) with pure Ketjen black (KBS) and with atomic vanadium and cobalt‐modified Ketjen black (VCKBS). In addition to the cathode material, the influence of crucial cell design parameters, namely electrolyte‐to‐sulfur (E/S) ratio and sulfur loading, on the cell resistances and battery performance is also compared. Electrochemical impedance spectroscopy (EIS) is applied to determine the individual cell resistances, whereas a system‐level performance model is used to estimate the system‐level specific energies and energy densities. The comparison of the cathodes shows that VCKBS significantly improves both cell‐ and system‐level performances, which are attributed to a significant decrease in cell resistances. The cells with higher sulfur loadings and lower E/S ratios show poorer performance for both cathodes. On the other hand, an E/S ratio of 6 mg L−1 can result in high cell‐ and system‐level performances for the VCKBS cathode. [ABSTRACT FROM AUTHOR]

Broad absorption spectra with efficient generation and separation of available charge carriers are indispensable requirements for promising semiconductor-based photocatalysts to achieve the ultimate goal of solar-to-fuel conversion. Here, Cu3−xSnS4 (x = 0−0.8) with copper vacancies have been prepared and fabricated via solvothermal process. The obtained copper vacancy materials have extended light absorption from ultraviolet to near-infrared-II region for its significant plasmonic effects. Time-resolved photoluminescence shows that the vacancies can simultaneously optimize charge carrier dynamics to boost the generation of long-lived active electrons for photocatalytic reduction. Density functional theory calculations and electrochemical characterizations further revealed that copper vacancies in Cu3−xSnS4 tend to enhance hydrogen's adsorption energy with an obvious decrease in its H2 evolution reaction (HER) overpotential. Furthermore, without any loadings, the H2 production rate was measured to be 9.5 mmol·h−1·g−1. The apparent quantum yield was measured to be 27% for wavelength λ > 380 nm. The solar energy conversion efficiency was measured to be 6.5% under visible-near infrared (vis-NIR) (λ > 420 nm). [ABSTRACT FROM AUTHOR]

Heterogeneous Fenton processes can overcome the generation of iron sludge and the production of more solid wastes. However, the performance of the catalyst is far from satisfactory, especially when wastewater has a pH > 3. To overcome these problems, porous urchin-like 3D Co(II)Co(III) layered double hydroxides (LDHs) were synthesized via a facile solvothermal process. The effect of various factors on the morphologies and formation mechanism was systematically investigated. The porous urchin-like 3D Co(II)–Co(III) LDH (CCLH 120) displayed the best catalytic activity for heterogeneous Fenton degradation by using 60 μL H2O2 and 0.1 g L−1 catalyst over a wide range of pH. The high surface area, porosity and good dispersibility of the nanoparticles stimulated the rapid and massive generation of reactive oxygen species in the heterogeneous Fenton reaction. The degradation efficiency for different types of dyes was measured to be 97%, 95% and 77% for methylene blue, Rhodamine B and methyl orange, respectively. The degradation rate of RhB is found to be 5.41 × 10−5 mol g−1 s−1. When applied in the treatment process of mining wastewater, the chemical oxygen demand (COD) values can efficiently be reduced from 817 mg L−1 to 30 mg L−1, which clearly indicates that the material has good potential as a high performance catalyst in Fenton reactions for treating industrial effluents. [ABSTRACT FROM AUTHOR]