Tuning of NaTaO3 Band Structure through Mn2+ Ion Doping and the Enhanced Visible Light Response

Pure and Mn-doped NaTaO3 nanoparticles were synthesized by a simple hydrothermal method. XRD and XPS results suggested that manganese ions were successfully doped into the NaTaO3 crystalline in Mn2+ state. UV-vis diffuse reflectance spectra revealed the obvious red-shift in the series of manganese doped NaTaO3 nanoparticles, resulting in a decrease in the band gap of NaTaO3 with the increase of Mn2+ doping concentration. The photo-degradation experiment indicated that manganese doped NaTaO3 showed good photocatalytic performance and methylene blue (MB) degradation is improved with lower doping concentration of manganese ions under visible light. The simulation of energy band structure by density functional theory unfolded that the substitution of Ta5+ ions by Mn2+ ions resulted in an intermediate band (TB) below the bottom of the conduction band (CB), which was mainly attributed to the state of Mn 3d.