Exploring the Photogenerated Charge Transfer Mechanism in Cu2O@MoS2 Heterojunction Photocatalyst Using Transient Absorption Spectroscopy

Both heterojunction and core-shell photocatalysts have demonstrated promising performance in photocatalytic CO2 conversions to fuels. However, fundamental knowledge of heterojunctions in core-shell structures is highly desired to facilitate the design of future photocatalysts. By combining advanced experimental characterizations and density functional theory (DFT) calculations, the role of the Cu2O@MoS2 heterojunction in photocatalytic CO2 conversions to fuels was investigated. We discovered that the charge dynamics and electron transfer properties of Cu2O@MoS2 photocatalysts are altered by the heterojunction and Cu2O underlayer due to the electron transfer from Cu2O to MoS2 and the change in CO2 adsorption strength on the hybrid catalyst surface. Consequently, more electrons can travel to the surrounding liquid environment to be consumed by CO2 reduction. This study provides experimental and theoretical investigations of the fundamental mechanisms of heterojunction core-shell photocatalysts.