Search

The effects of anion-tuning on cobalt-based chalcogenides for OER in weakly alkaline seawater are comprehensively investigated via DFT, XAS, and XPS, and S substitution is proven to optimize the electronic structure of active site to prevent Cl* from transforming to ClO- for anti-corrosion. Co 3 S 4 could stably operate at the high current density of 100 mA cm−2 for 100h without any performance degradation. [Display omitted] • Co 3 S 4 and Co 3 Se 4 were transformed from the Co 3 O 4 precursor by hydrothermal method. • DFT predicts the possible active sites and mechanisms of OER and HCER in seawater. • S and Se substitution increases energy barrier of Cl* to ClO- for anti-corrosion. • S and Se could promote Co site transforming to active phase. • Co 3 S 4 stably operates at OER current density of 100 mA cm−2 in weakly alkaline seawater for 100 h and netrual seawater for 20 h. Regulating the electronic structure is of great importance for improving the performance, stability, and selectivity of seawater splitting catalysts. Herein, cobalt-based oxide and chalcogenide (Co 3 X 4 , X = O, S, and Se) are synthesized to investigate the effect of anions on the electronic structure, catalytic performance and selectivity of the seawater oxidation catalysts. The theoretical calculations predict the possible active sites of oxygen evolution reaction and hypochlorite evolution reaction. Then the experimental characterization and calculation results demonstrate that S and Se substitution could regulate the electronic structure and d-band center of Co site, enhance the metallicity of catalysts. Moreover, the energy barrier of Cl* conversion to ClO- could be modulated for preventing the formation of ClO- by anions regulating. Consequently, Co 3 S 4 could stably operate at a current density of 100 mA cm−2 in 0.1 M KOH + 0.6 M NaCl for 100 h and in neutral seawater for 20 h. [ABSTRACT FROM AUTHOR]

Compounds with Cs 3 CoCl 5 structure usually exhibit a large Debay temperature with a large band gap, which has been considered as new host materials for WLED application. Oxide materials of the Cs 3 CoCl 5 structure have great luminescence characteristics, thus it is more worthwhile to research Cl-based materials with higher electronegativity. Here, an Mn2+ activated Cs 3 ZnCl 5 narrow band green emitting phosphor was developed and investigated in detail. Ternary alkaline chloride Cs 3 ZnCl 5 was successfully prepared by a coprecipitation method. XRD refinement, SEM and XPS have proved the successful preparation of Cs 3 ZnCl 5 : 6%Mn2+ with a single phase. The electronic structure investigation clearly states that Cs 3 ZnCl 5 has a large band gap with Eg∼4.467 eV. The Cs 3 ZnCl 5 : 6%Mn2+ phosphor can also generate green light with a peak wavelength of 525 nm and a fullwidth at half-maximum (FWHM) of 47 nm when excited by blue light at 451 nm. The luminescent property, as well as the concentration-dependent emission decay behavior of Cs 3 ZnCl 5 : 6%Mn2+ at room temperature, were studied. Over the temperature range of 30–120 °C, the thermal quenching performance of Cs 3 ZnCl 5 : 6%Mn2+ was investigated, and the related mechanism was discussed through thermoluminescence analysis. Electron traps transmit energy to the Mn2+ luminescence center after 120 °C, which will increase the emission intensity. Finally, a blue light-pumped white LED was constructed using this phosphor in combination with commercially available red phosphors. The findings above suggested that Cs 3 ZnCl 5 : 6%Mn2+ could be served as a potential green-emitting phosphor for white light-emitting diodes. • The Cs 3 ZnCl 5 : Mn2+ phosphors are successful prepared. • The abnormal thermal quenching have been discussed in detail. • The Cs 3 ZnCl 5 : Mn2+ phosphors have a green emitting at 525 nm. • The Cs 3 ZnCl 5 : Mn2+ phosphors can be used in WLEDs. [ABSTRACT FROM AUTHOR]

Oxygen vacancy in different oxide systems shows up as a crucial parameter in modulation of the emerging application-oriented functionalities. A systematic exploration on the relation between oxygen vacancy and electronic structure of the La0.2Sr0.8MnO3 (LSMO) thin film has been carried out through sequential surface treatments followed by a series of wide scan XPS, O 1s XPS, O-K edge XAS, Mn-L edge XAS and work function measurements. Experimental results demonstrate mutual corroborative certifying evidences in between the different photoemission spectral measurements on the evolution and influence of the oxygen vacancy. Spectral characteristic features observed in the work are applicable using as justification fingerprint for the existence, modulation, or elimination of the oxygen vacancy in similar perovskite type oxide systems. [ABSTRACT FROM AUTHOR]