Preparation and Photocatalytic Mechanism of Vanadium Doped NaTaO3 Nanoparticles

Pure and vanadium doped NaTaO3 nanoparticles were synthesized by hydrothermal conditions. From XRD studies, both pure as well as vanadium doped NaTaO3 are found to show pure orthorhombic phase of tatanlate. STEM studies show the formation of cube shape particles in all the samples with a particle size about 70 nm. UV-vis diffuse reflectance spectra clearly indicates the red-shift in the series of vanadium doped NaTaO3 catalysts, resulting in a decrease in the band gap of NaTaO3 caused by substitution of V5+ ions at Ta5+ site with an increase of vanadium doping concentration in NaTaO3. The results reveal that Vanadium doped NaTaO3 show good photocatalytic performance under visible light and RhodamineB (RB) degradation is improved with Vanadium doping. The photocatalytic mechanism was discussed by density functional theory. V5+ ions substitution of Ta5+ ions results in an intermediate band (IB) below the bottom of the conduction band (CB), which is mainly attributed to the state of V 3d. Meanwhile the broadening of valence band is formed due to the hybridization between the V 3d and O 2p states. Both these factors increase the transient behavior of the photogenerated charge carriers and inhibit the recombination of e-h+ pairs, showing enhanced activities over the entire visible region.