Charge transfer kinetic analysis of S-scheme heterojunction by femtosecond transient absorption spectrum

An emerging S-scheme photocatalyst consisting of Ni-doped Zn0.2Cd0.8S quantum dots and TiO2 microspheres has been reported to show excellent H2 production performance and high benzylidene benzylamine evolution efficiency. To monitor the charge transfer dynamics in this S-scheme heterojunction, femtosecond transient absorption spectroscopy measurements are conducted. The charge transfer kinetic analysis confirms that S-scheme heterojunction promotes interfacial electron transfer and accelerates hole consumption. This work provides an in-depth explanation for the enhanced photocatalytic performance of S-scheme photocatalysts from the perspective of charge dynamics.