Band gap engineering by anion doping in the photocatalyst BiTaO-4: First principle calculations

摘要

We have shown the effect of mono and co-doping of non-metallic anion atoms on the electronic structure in BiTaO_4 using the first-principles method. It can improve the pho-tocatalytic efficiency for hydrogen production in the presence of visible sunlight. It is found that the band gap of BiTaO_4 has been reduced significantly up to 54% with different non-metallic doping. Electronic structure analysis shows that the doping of nitrogen is able to reduce the band gap of BiTaO_4 due to the impurity N 2p state at the upper edge of the valence band. In case of C or C-S doped BiTaO_4, double occupied (filled) states have been observed deep inside the band gap of BiTaO_4. The large reduction of band gap has been achieved, which increases the visible light absorption. These results indicate that the doping of non-metallic element in BiTaO_4 is a promising candidate for the photocatalyst due to its reasonable band gap.