Density functional theory insights on photocatalytic ability of CuO/TiO2 and CuO/ZnO

Photocatalytic conversion of TiO2 based materials for water splitting, dye degradation, and carbon dioxide utilization reactions are not only scientifically interesting but also promising from industrial perspectives. It is almost imperative to screen a potential material through systematic combination of understanding and testing. Recently, Density Functional Theory (DFT) assisted electronic property computation and mechanism understanding has opened new possibilities to design interesting photocatalysts. Our present study is focused to report band structure and density of states for TiO2, ZnO which are considered as base materials for photocatalysis. Again, CuO being an active material for CO2 photoreduction, the effect of addition on the base photocatalysts was highlighted in the present study. The heterostructure model was studied to reveal the modification of bands and electronic states near the Fermi Energy Level. Moreover, separation efficiency (D) was calculated as the ratio of the effective mass of holes and the excited electrons respectively, an indirect measure of the recombination rate of the electron-hole pairs. It is reported that the D values of these photocatalysts decreased as 8.11 (CuO/TiO2) > 7.22 (CuO/ZnO) > 6.103 (TiO2) > 3.302 (ZnO). Furthermore, attempts are being made to correlate the separation efficiency with CO2 conversion by mechanism-based understanding.