The electronic structure of Eu-doped NaTaO3 in Na-rich environment is investigated by the first-principles theory. By simulating the two different models of Eu3＋ ions selectively located in Ta and Na sites, respectiv...The electronic structure of Eu-doped NaTaO3 in Na-rich environment is investigated by the first-principles theory. By simulating the two different models of Eu3＋ ions selectively located in Ta and Na sites, respectively, the band gaps of two Eu-doped NaTaO3 models were all narrowed, which were assigned to lattice defects and impurity band of the Eu dopent. For the model of Eu3＋ ions located in the Na＋ sites of NaTaO3, the new impurity band mainly composited of Eu 4f orbital appeared at the top over the valence band, indicating the enhanced oxidative ability. For the model of Eu3＋ ions located in the Ta5＋ sites of NaTaO3, a midgap state generated was located at the bottom of conduct band and the band potential shifted up, confirming the strong reductive ability in the Na-rich enviornment. The densities of electron states were significantly increased in both the conduction and valence bands in Na-rich model, which resulted in the increased carrier migration rate and thus photocatalytic activity enhancement. It is proposed that Eu3＋ ions doping at the Ta sites could enhance the reduced photocatalytic performance via controlling the nonstoichiometric Na/Ta molar ratio in the Eu-doped NaTaO3 system.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.21973022)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012353).
基金Financially supported by the National Natural Science Foundation of China(No.21267014 and 21567017)
文摘The electronic structure of Eu-doped NaTaO3 in Na-rich environment is investigated by the first-principles theory. By simulating the two different models of Eu3＋ ions selectively located in Ta and Na sites, respectively, the band gaps of two Eu-doped NaTaO3 models were all narrowed, which were assigned to lattice defects and impurity band of the Eu dopent. For the model of Eu3＋ ions located in the Na＋ sites of NaTaO3, the new impurity band mainly composited of Eu 4f orbital appeared at the top over the valence band, indicating the enhanced oxidative ability. For the model of Eu3＋ ions located in the Ta5＋ sites of NaTaO3, a midgap state generated was located at the bottom of conduct band and the band potential shifted up, confirming the strong reductive ability in the Na-rich enviornment. The densities of electron states were significantly increased in both the conduction and valence bands in Na-rich model, which resulted in the increased carrier migration rate and thus photocatalytic activity enhancement. It is proposed that Eu3＋ ions doping at the Ta sites could enhance the reduced photocatalytic performance via controlling the nonstoichiometric Na/Ta molar ratio in the Eu-doped NaTaO3 system.
