Nitrogen concentration influence on N-NaTaO3 from first principles

Abstract

First-principles density functional theory electronic structure calculations were carried out for N-doped NaTaO3 to evaluate the effects of the nitrogen doping concentration on the electronic structures and the photocatalytic activity of NaTaO3. When nitrogen doping at the lower levels (x ≦̸ 0.0417), the isolated N 2p states are formed above the O 2p states while the bottom of conduction band (CB) shifts little in N-doped NaTaO3. With increasing nitrogen doping levels (x ⩾ 0.0625), the N 2p states begin to mix with the O 2p states and thus move the top of valence band (VB) upwards in contrast to the corresponding NaTaO3. Based on the calculated energy band structures and Mulliken electronegativity theory, the schematic illustrations of N-doped NaTaO3 with different concentrations are tentatively proposed. The present study will provide a theoretical basis for developing the nitrogen-doped multimetal oxide photocatalysts with visible-light response.