Vanadium-based compounds and heterostructures as functional sulfur catalysts for lithium-sulfur battery cathodes

Lithium-sulfur(Li-S) batteries have attracted wide attention for their high theoretical energy density, low cost, and environmental friendliness. However, the shuttle effect of polysulfides and the insulation of active materials severely restrict the development of Li-S batteries. Constructing conductive sulfur scaffolds with catalytic conversion capability for cathodes is an efficient approach to solving above issues.Vanadium-based compounds and their heterostructures have recently emerged as f...     

Crystal facet engineering coexposed CuIn(200) and In(101) in CuIn alloy nanocatalysts enabling selective and stable CO2 electroreduction

The electrocatalytic carbon dioxide reduction reaction(eCO₂RR) into high-value-added chemicals and fuels is a promising strategy to mitigate global warming.However,it remains a significant stumbling block to the rationally tuning lattice plane of the catalyst with high activity to produce the target product in the eCO₂RR process.To attempt to solve this problem,the Culn bimetallic alloy nanocatalyst with specifically exposed lattice planes is modulated and electrodeposited ...     

Chemical bonding of perovskite LaFeO3 with Li1.2Mn0.6Ni0.2O2 to moderate anion redox for achieving high cycling stability

Oxygen anion redox reaction provides a high theoretical capacity for Li-rich manganese-based cathodes.However, irreversible surface oxygen release often results in further oxygen loss and exacerbates the decomposition of the electrolyte, which could reduce the capacity contribution from the anionic redox and produce more acidic substances to corrode the surface of the material. In this paper, the surface oxygen release is suppressed by moderating oxygen anion redox activity via constructing chem...     

Geometric quantities of lower doubly excited bound states of helium

Expectation values of single electron and interelectronic geometric quantities such as $\langle r\rangle$, $\langle r_{12}\rangle$, $\langle r_<\rangle$, $\langle r_>\rangle$, $\langle \cos\theta_{12}\rangle$ and $\langle \theta_{12}\rangle$ are calculated for doubly excited $2{\rm p}n{\rm p}\,{}^1P^{\,\rm e}\,(3\leq n\leq5),\, 2{\rm p}n{\rm p}\,{}^3\!P^{\,\rm e}\,(2\leq n\leq5)$ and $2{\rm p}n{\rm d}\,{}^{1,3}D^{\,\rm o}\,(3\leq n\leq5)$ states of helium using Hylleraas-$B$-spline basis set. The energy levels converge to at least 10 significant digits in our calculations. The extrapolated values of geometric quantities except for $\langle \theta_{12}\rangle$ reach 10 significant digits as well; $\langle \theta_{12}\rangle$ reaches at least 7 significant digits using a multipole expansion approach. Our results provide a precise reference for future research.     

Prospective study on observations of γ-ray sources in the Galaxy using the HADAR experiment

The High Altitude Detection of Astronomical Radiation (HADAR) experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique. It focuses the Cherenkov light emitted by extensive air showers through a large aperture water-lens system for observing very-high-energy γ-rays and cosmic rays. With the advantages of a large field-of-view (FOV) and low energy threshold, the HADAR experiment operates in a large-scale sky scanning mode to observe galactic sources. This study presents the prospects of using the HADAR experiment for the sky survey of TeV γ-ray sources from TeVCat and provids a one-year survey of statistical significance. Results from the simulation show that a total of 23 galactic point sources, including five supernova remnant sources and superbubbles, four pulsar wind nebula sources, and 14 unidentified sources, were detected in the HADAR FOV with a significance greater than 5 standard deviations (σ). The statistical significance for the Crab Nebula during one year of operation reached 346.0 σ and the one-year integral sensitivity of HADAR above 1 TeV was ~1.3%–2.4% of the flux from the Crab Nebula.     

Theoretical study on the mechanism for the excited-state double proton transfer process of an asymmetric Schiff base ligand

Excited-state double proton transfer (ESDPT) in the 1-[(2-hydroxy-3-methoxy-benzylidene)-hydrazonomethyl]-naphthalen-2-ol (HYDRAVH₂) ligand was studied by the density functional theory and time-dependent density functional theory method. The analysis of frontier molecular orbitals, infrared spectra, and non-covalent interactions have cross-validated that the asymmetric structure has an influence on the proton transfer, which makes the proton transfer ability of the two hydrogen protons different. The potential energy surfaces in both S₀ and S₁ states were scanned with varying O-H bond lengths. The results of potential energy surface analysis adequately proved that the HYDRAVH₂ can undergo the ESDPT process in the S₁ state and the double proton transfer process is a stepwise proton transfer mechanism. Our work can pave the way towards the design and synthesis of new molecules.     

Efficient soluble polymer-supported sharpless alkene epoxidation catalysts

High chemical yields and good enantiomeric excesses are obtained by using soluble polymer-supported tartrate ester in the epoxidation of trans-hex-2-en-1-ol using Ti(OPri)4/tert-butyl hydroperoxide.     

D-Proline capped gold nanoclusters for turn-on detection of serum Raltitrexed

Using D-proline (D-Pro) as the reducing agent and capper, D-Pro@AuNCs was rapidly constructed. Its fluorescence could be quenched by AuNPs. Due to the electrostatic interaction between anticancer drug Raltitrexed (RTX) and AuNPs induced fluorescence "turn-on" principle, the resultant fluorescent probe exhibited good selectivity and sensitivity for detecting RTX in rat serums.