Search

The Z-scheme Se/BiVO4 photocatalysts were successfully prepared by chemical reduction and hydrothermal methods. Ethanol had the effect of solubilizing a-Se and insoluble t-Se during aging, which was critical for the rapid growth of t-Se rods. Compared with pure Se rods and BiVO4, the Z-scheme Se/BiVO4 exhibits enhanced photocatalytic activity for rhodamine B (RhB) degradation under visible-light irradiation. The photoluminescence detection technology of terephthalic acid spectra shows that ·OH is the major active radical in the degradation of RhB by Se/BiVO4. Based on the transient photocurrent measurements and band structures, it can be concluded that the Z-scheme structure of Se/BiVO4 not only enhances the photogenerated electrons and holes migration rates but also to provide higher redox ability. With the enhanced photocatalytic performance, Se/BiVO4 can be potentially applied for the environmental remediation. [ABSTRACT FROM AUTHOR]

Abstract: To understand the photocatalytic activity of Bi2WO6 for water splitting, the electronic structures of N- and Mo-monodoped and N/Mo-codoped Bi2WO6 are investigated based on first-principles calculations. Our results indicate that the band gap of N/Mo-codoped Bi2WO6 reduces by 0.19eV and the smaller driving force is required for the water-splitting oxidation process. The calculated binding energy of the defect pairs shows that N/Mo-codoping in Bi2WO6 is more feasible than mono-doping, indicating N/Mo-codoped Bi2WO6 is a potential candidate for the photocatalytic water splitting. [Copyright &y& Elsevier]

Abstract: The electronic properties of Bi2 MO6 (M=Mo and W) are studied by using the first-principles calculations. It is attributed to its smaller electron effective mass that Bi2WO6 has higher photocatalytic activity than Bi2MoO6. The oxygen vacancy in Bi2 MO6 serves as a trapping center of photogenerated electrons and thus is in favor of the photocatalytic efficiency. Nitrogen-doping induces localized structure distortion and thus improves the separation of photogenerated electron-hole pairs. Moreover, band gaps decrease obviously with doping concentration increasing, therefore the photoabsorption edges will give rise to a redshift in Bi2 MO6. [Copyright &y& Elsevier]

Two new diamond-like (DL) chalcogenides, Li2MgGeSe4 and Li2MgSnSe4, have been successfully synthesized using a conventional high-temperature solid-state method. The two compounds crystallize in the non-centrosymmetric space group Pmn21 with a = 8.402 (14) Å, b = 7.181 (12) Å, c = 6.728 (11) Å, Z = 2 for Li2MgSnSe4, and a = 8.2961 (7) Å, b = 7.0069 (5) Å, c = 6.6116 (6) Å, Z = 2 for Li2MgGeSe4. The calculated results show that the second harmonic generation (SHG) coefficients of Li2MgSnSe4 (d33 = 12.19 pm/v) and Li2MgGeSe4 (d33 = −14.77 pm/v), mainly deriving from the [MSe4] (M = Ge, Sn) tetrahedral units, are close to the one in the benchmark AgGaS2 (d14 = 13.7 pm/V). The calculated band gaps for Li2MgSnSe4 and Li2MgGeSe4 are 2.42 and 2.44 eV, respectively. Moreover, the two compounds are the first series of alkali and alkaline-earth metal DL compounds in the I2-II-IV-VI4 family, enriching the structural diversity of DL compounds. [ABSTRACT FROM AUTHOR]

Exploration of the versatility of materials is very important for increasing the utilization of materials. Herein, we successfully prepared Bi 4 O 5 I 2 powders via a facile solvothermal method. The Bi 4 O 5 I 2 photocatalyst exhibited significantly higher photocatalytic activity as compared to the common BiOI photocatalyst in the degradation of methyl orange, methylene blue and rhodamine B under visible light irradiation. Especially, for the degradation of methyl orange, the photocatalytic activity of Bi 4 O 5 I 2 is about 10 times that of BiOI. Moreover, Bi 4 O 5 I 2 exhibits an extremely high second harmonic generation response of about 20 × KDP (the benchmark) estimated by the unbiased ab initio calculations. The coexisting multifunction of Bi 4 O 5 I 2 is mainly because of the increased dipole moment due to the stereochemical activity of lone pairs that promotes separation and transfer of photogenerated carriers, then enhances the photocatalytic activity and results in a high second harmonic generation response. This indicates that Bi 4 O 5 I 2 may have good potential applications in photocatalytic and nonlinear optical fields., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)