The Oretical Study Of Metal-doped ?-Ga₂O₃ Photocatalysts For Overall Water Splitting

The effects of different metal dopants on the photocatalytic performance of?-Ga₂O₃-based photocatalyst were explored using first-principles density functional theory calculations.Experimentally,Ca-doped?-Ga₂O₃ was found to increase the photocatalytic activity by about three times compared with undoped photocatalyst.However,the same host doped with La had minor influence on photocatalytic performance.Doping with Ti leaded to very low H₂ and O₂ evolution rate.The analysis of electronic structures illustrated the mechanisms that influence the photocatalytic efficiency.Our calculated results suggested that the energy states introduced by dopant Ca in the bandgap of?-Ga₂O₃ were close to the valence band maximum.The new states allowed for efficient electron replenishment and thus reduced the probability of trapping electrons from the conduction band.In contrast,the impurity states introduced by dopant Ti were significantly higher than the valence band,making them an isolated recombination center and thus badly decreasing the rate of water splitting reaction.The addition of La had no effect on the electronic structure of?-Ga₂O₃,which had seldom influence of photocatalytic activity.