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

Abstract

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.

Achieving indirect‐to‐direct band gap transition and enhanced photocatalytic performance in blue phosphorene through doping and strain

“…Considering that the water‐splitting reaction might be performed at neutral pH (7) rather than acidic pH (0), the photocatalytic performance of these doped systems at neutral environment should be further discussed. From the literature, 13,60 it is known that changes in pH closely affect the reduction potential for H + /H 2 and the oxidation potential for O 2 /H 2 O, which are determined by the following equations: …”

“…Considering that the water-splitting reaction might be performed at neutral pH (7) rather than acidic pH (0), the photocatalytic performance of these doped systems at neutral environment should be further discussed. From the literature, 13,60 it is known that changes in pH closely affect the reduction potential for H + /H 2 and the oxidation potential for O 2 /H 2 O, which are determined by the following equations: Based on these equations, the redox potentials for water in Figure 5 are shifted upward after increasing the pH value. Thus, the band edges of all As/Sb-doped BP systems, including those under −4% strain, can straddle the redox potential of H + /H 2 and O 2 /H 2 O at pH = 7.…”

Recent Advances in Niobium-Based Materials for Photocatalytic Solar Fuel Production

“…The potential of niobates structures for water splitting has also been demonstrated by some theoretical works. The perovskite-type niobate NaNbO 3 was selected by Wang and coauthors to investigate the effect of anionic monodoping with N, C, P, and S dopants, as well as with (N + N), (C + S), and (N + P) codoping pairs by hybrid density functional theory calculations [45]. At first, the direct band gap of pure cubic NaNbO 3 was predicted to be 3.30 eV, with the conduction band mainly formed by Nb-4d orbitals and valence band by the O-2p orbitals, and almost no Na-related states around the band edge were found, indicating that the Na atoms have negligible effects on the electronic structures near the Fermi level.…”

Z-scheme LaCoO3/C3N5 for efficient full-spectrum light-simulated solar photocatalytic hydrogen generation

“…Recently perovskite-type semiconductor materials have aroused great interest among researchers. [15][16][17][18][19][20][21][22] Because of their adjustable band gap, strong photocorrosion resistance and sufficient oxygen vacancies, they have become very promising photocatalysts. [23][24][25][26][27][28] With these characteristics, they are excellent materials for solar cells and photocatalytic reactions, and they have attracted great attention from researchers.…”