The effects of Co/N dopants on the electronic, redox potential, optical, and photocatalytic water-splitting properties of TiO2: First principles calculations

Abstract

The crystal structure, formation energy, electronic and optical properties of undoped, Co, N doped and co-doped TiO2 were investigated by first principles calculations. Considering the potential of water redox reaction of these systems indicate that only N-, Co-1N- and Co-2N co-doped TiO2 meet the requirement of the photosplitting water. Moreover, the optical absorption threshold and absorption area of Co-2N co-doped TiO2 are obviously enlarged compared with the undoped TiO2. Co-2N co-doped TiO2 has the highest light absorption efficiency and hydrogen production efficiency, due to the presence of curved and broad impurity levels that greatly improve the carriers’ mobility and separation.