Double-Hole-Mediated Codoping on KNbO 3 for Visible Light Photocatalysis

Physica Status Solidi (b)

Tang

Geng

et al. 2019

Self Cite

Using hybrid density functional calculations, the influence of rotation angles on the photocatalytic performance of 2D ZnO/GaN heterostructures is explored. The results show that the bandgaps and band alignments for ZnO/GaN heterostructures can be tuned by rotation angles. Rotated ZnO/GaN heterostructures are favorable for visible light absorption. Band alignments of different rotated ZnO/GaN heterostructures are severally thermodynamically favorable for spontaneous generation of hydrogen and oxygen with the pH scope of 0–14, 3–14, 2–14, 1–14, 1–14, and 4–14. In addition, the formed built‐in electric field across ZnO/GaN heterostructure interface promotes photogenerated carrier migration and inhibits photogenerated carrier recombination. These factors make rotated ZnO/GaN heterostructures promising for visible light water splitting. The findings pay a new way to design 2D heterostructures used for photocatalytic water splitting.

Section: Introductionmentioning

confidence: 99%

Rotation Tunable Photocatalytic Properties of ZnO/GaN Heterostructures

Physica Status Solidi (b)

Tang

Geng

et al. 2019

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“…The band‐gap for N–N co‐doped (i) is reduced to 1.237 eV with the VBM contributed by a lot of Mo 4d, S 3p states and a little of N 3p states and the CBM contributed by Mo 4d states. Some unoccupied states appear above the Fermi level, which is different from the case of doped TiO 2 , BiNbO 4 , BiTaO 4 , ZrO 2 , NaTaO 3 , SrTiO 3 , KNbO 3 , and La 2 Ti 2 O 7 , because N–N coupling does not happen in the co‐doped (i). These unoccupied states promoting the recombination of electron–hole will suppress the photocatalytic activity, which makes N–N co‐doped (i) not suitable for photocatalysis.…”

Section: Resultsmentioning

confidence: 76%

“…N mono‐doped ML‐MoS 2 has a direct band‐gap of 1.265 eV with the VBM and CBM locating at the same k‐point of Г. The VBM is mainly comprised of Mo 4d and S 3p states with no N 2p states appearing near the VBM, which is entirely different from the case of N mono‐doped TiO 2 , BiNbO 4 , BiTaO 4 , ZrO 2 , NaTaO 3 , SrTiO 3 , KNbO 3 , La 2 Ti 2 O 7 , etc. This is attributed to the reason that N 2p orbital energy is higher than the O 2p orbital energy but lower than the S 3p orbital energy .…”

Section: Resultsmentioning

confidence: 93%

“…Compared with the charge compensated co‐doping, the double‐hole‐mediated coupling of dopants, which can not only passivate the mid‐gap states but also narrow the band‐gap, has been demonstrated more efficient to enhance the photocatalytic activity of TiO 2 . The double‐hole‐mediated co‐doping strategy has been applied in many other photocatalysts, such as BiNbO 4 , BiTaO 4 , ZrO 2 , NaTaO 3 , SrTiO 3 , KNbO 3 , La 2 Ti 2 O 7 , etc. to improve their photocatalytic ability.…”

Section: Introductionmentioning

confidence: 99%

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Anion–Anion Co‐Doped Monolayer MoS₂ for Visible Light Photocatalysis

Physica Status Solidi (b)

Yuan

Kuang

et al. 2017

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The structural, electronic, and optical properties of N, P mono‐doped and N–N, N–P, P–P co‐doped monolayer MoS2 (ML‐MoS2) have been calculated in contrast with the pure ML‐MoS2 so as to investigate if double‐hole‐mediated co‐doping with anion–anion pairs will improve the photocatalytic activity of ML‐MoS2. The unfilled impurity states appearing in the N‐doped system and the formation of S vacancy in N, P mono‐doped systems suppress the photocatalytic activities of N and P mono‐doped systems. N–P co‐doped [in configuration (ii)] as well as N–N and P–P co‐doped ML‐MoS2 also introduce unoccupied impurity states above the Fermi levels, and these impurity states accelerating the recombination of photo‐generated charge carriers will suppress the photocatalytic activity. The N–P co‐doped [in configuration (i)] ML‐MoS2 has the suitable band‐gap with respect to the water redox levels, and N–P co‐doping will suppress the formation of MoS2 bilayer. Therefore, N–P co‐doped (i) is a promising visible light photocatalyst for water splitting.

“…Besides cation‐anion codoping, codoping with two anionic elements has emerged as an effective path for band gap engineering of the perovskite‐type photocatalysts, such as SrTiO 3 , Sr 2 Nb 2 O 7 , NaTaO 3 , and KNbO 3 . The double‐hole‐mediated coupling between the anionic dopants creates fully filled delocalized intermediate bands lying above the valence band, thus not only the band gap is reduced significantly but also the overall stability is improved .…”

Section: Introductionmentioning

confidence: 99%

Double‐hole‐mediated coupling of anionic dopants in perovskite NaNbO₃ for efficient solar water splitting

Int J of Quantum Chemistry

Teng

et al. 2019

Doping is an effective strategy to improve the photocatalytic performances of semiconductor photocatalyst for water splitting. In this work, we perform extensive hybrid density functional calculations to investigate perovskite NaNbO3 with anionic monodoping with N, C, P, and S dopants as well as with (N + N), (C + S), and (N + P) codoping pairs. Theoretical results clearly reveal that the band structures of NaNbO3 can be effectively tailored by introducing double‐hole‐mediated coupling of anion‐anion pairs. Compared with the monodoping cases, the anion‐anion codoped NaNbO3 systems not only have substantially narrowed band gaps, but also can eliminate the unoccupied localized states appearing above the Fermi level, which are disastrous for photocatalysis as they may trap the photogenerated carriers. Optical absorption curves further convince that the codoped NaNbO3 can effectively harvest visible light. The band edge positions with respect to the redox potentials of water demonstrate that the (N + N) codoped NaNbO3 are desirable for efficient solar water splitting.