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Bi(1-x)La(x)CuSeO as New Tunable Full Solar Light Active Photocatalysts.

Wang H, Li S, Liu Y, Ding J, Lin YH, Xu H, Xu B, Nan CW - Sci Rep (2016)

Bottom Line: However, efficiently harvesting solar energy for photocatalysis remains a pressing challenge, and the charge kinetics and mechanism of the photocatalytic process is far from being well understood.Our measurements and density-functional-theory calculations reveal that the effective mass and mobility of the carriers in BiCuSeO can be tuned by the La-doping, which are responsible for the tunable photocatalytic activity.Our findings may offer new perspectives for understanding the mechanism of photocatalysis through modulating the charge mobility and the effective mass of carriers and provide a guidance for designing efficient photocatalyts.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.

ABSTRACT
Photocatalysis is attracting enormous interest driven by the great promise of addressing current energy and environmental crises by converting solar light directly into chemical energy. However, efficiently harvesting solar energy for photocatalysis remains a pressing challenge, and the charge kinetics and mechanism of the photocatalytic process is far from being well understood. Here we report a new full solar spectrum driven photocatalyst in the system of a layered oxyselenide BiCuSeO with good photocatalytic activity for degradation of organic pollutants and chemical stability under light irradiation, and the photocatalytic performance of BiCuSeO can be further improved by band gap engineering with introduction of La. Our measurements and density-functional-theory calculations reveal that the effective mass and mobility of the carriers in BiCuSeO can be tuned by the La-doping, which are responsible for the tunable photocatalytic activity. Our findings may offer new perspectives for understanding the mechanism of photocatalysis through modulating the charge mobility and the effective mass of carriers and provide a guidance for designing efficient photocatalyts.

No MeSH data available.


(a) Total density of state near the Fermi level and (b–d) the valence band maximum of Bi1−xLaxCuSeO with increasing La content.
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f4: (a) Total density of state near the Fermi level and (b–d) the valence band maximum of Bi1−xLaxCuSeO with increasing La content.

Mentions: BiCuSeO is reported as a multiband semiconductor34. The top of the valence band (L band) consists of a hole pocket (located on Γ-M line of the Brillouin zone), which has been proven to be a heavy band. The secondary valence band maximum observed on the Γ-X line and at the Z points is a light band (Σ band). The band structures of Bi1−xLaxCuSeO were investigated by theoretical calculation using DFT plus on-site repulsion U (DFT+U) in the Vienna ab initio Simulation Package (VASP). The effective masses of hole located at the top of light band and heavy band are 0.81 me and 1.91 me (where me is the free-electron mass), respectively, and the light band locates slightly lower than the heavy band. That is consistent with reported feature50. The broadening of band gap with the introduction of La was confirmed in plots of total density of states (Fig. 4a). The increasing tendency of band gap is consistent with the experimental value estimated by the absorption spectra (Fig. 1b). The calculated band gap of pristine BiCuSeO is 0.54 eV, which is smaller than experimental value. According to the calculated results, the VBM (or CBM) shifts to more positive induced by the doping of La, resulting in broadening of band gap (Fig. S6, Supplementary Information). The conduction band minimum is at the Z point, and the valence band maximum is on the M–G line, indicating that BiCuSeO is an indirect band gap semiconductor.


Bi(1-x)La(x)CuSeO as New Tunable Full Solar Light Active Photocatalysts.

Wang H, Li S, Liu Y, Ding J, Lin YH, Xu H, Xu B, Nan CW - Sci Rep (2016)

(a) Total density of state near the Fermi level and (b–d) the valence band maximum of Bi1−xLaxCuSeO with increasing La content.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837348&req=5

f4: (a) Total density of state near the Fermi level and (b–d) the valence band maximum of Bi1−xLaxCuSeO with increasing La content.
Mentions: BiCuSeO is reported as a multiband semiconductor34. The top of the valence band (L band) consists of a hole pocket (located on Γ-M line of the Brillouin zone), which has been proven to be a heavy band. The secondary valence band maximum observed on the Γ-X line and at the Z points is a light band (Σ band). The band structures of Bi1−xLaxCuSeO were investigated by theoretical calculation using DFT plus on-site repulsion U (DFT+U) in the Vienna ab initio Simulation Package (VASP). The effective masses of hole located at the top of light band and heavy band are 0.81 me and 1.91 me (where me is the free-electron mass), respectively, and the light band locates slightly lower than the heavy band. That is consistent with reported feature50. The broadening of band gap with the introduction of La was confirmed in plots of total density of states (Fig. 4a). The increasing tendency of band gap is consistent with the experimental value estimated by the absorption spectra (Fig. 1b). The calculated band gap of pristine BiCuSeO is 0.54 eV, which is smaller than experimental value. According to the calculated results, the VBM (or CBM) shifts to more positive induced by the doping of La, resulting in broadening of band gap (Fig. S6, Supplementary Information). The conduction band minimum is at the Z point, and the valence band maximum is on the M–G line, indicating that BiCuSeO is an indirect band gap semiconductor.

Bottom Line: However, efficiently harvesting solar energy for photocatalysis remains a pressing challenge, and the charge kinetics and mechanism of the photocatalytic process is far from being well understood.Our measurements and density-functional-theory calculations reveal that the effective mass and mobility of the carriers in BiCuSeO can be tuned by the La-doping, which are responsible for the tunable photocatalytic activity.Our findings may offer new perspectives for understanding the mechanism of photocatalysis through modulating the charge mobility and the effective mass of carriers and provide a guidance for designing efficient photocatalyts.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.

ABSTRACT
Photocatalysis is attracting enormous interest driven by the great promise of addressing current energy and environmental crises by converting solar light directly into chemical energy. However, efficiently harvesting solar energy for photocatalysis remains a pressing challenge, and the charge kinetics and mechanism of the photocatalytic process is far from being well understood. Here we report a new full solar spectrum driven photocatalyst in the system of a layered oxyselenide BiCuSeO with good photocatalytic activity for degradation of organic pollutants and chemical stability under light irradiation, and the photocatalytic performance of BiCuSeO can be further improved by band gap engineering with introduction of La. Our measurements and density-functional-theory calculations reveal that the effective mass and mobility of the carriers in BiCuSeO can be tuned by the La-doping, which are responsible for the tunable photocatalytic activity. Our findings may offer new perspectives for understanding the mechanism of photocatalysis through modulating the charge mobility and the effective mass of carriers and provide a guidance for designing efficient photocatalyts.

No MeSH data available.