Ultrafast Hot Electron Transfer and Trap-State Mediated Charge Carrier Separation toward Enhanced Photocatalytic Activity in g-C3N4/ZnIn2S4 Heterostructure

Comprehensive understanding of charge carrier dynamics in the heterostructure based photocatalytic materials will strengthen their candidature as future solar energy harvesting resources. Here, in this work, the g-C3N4(CN)/ZnIn2S4 (ZIS) heterostructure was successfully synthesized and a direct spectroscopic correlation was established between excited-state charge carrier dynamics and enhanced photocatalytic activity using ultrafast transient absorption (TA) spectroscopy. TA analysis demonstrated the dominance of hot electron transfer over the band edge one. The photogenerated hot electrons migrated from the high-energy excitonic states of CN toward ZIS in the subpicosecond time scale. Broad-band (UV to NIR) ultrafast transient pump-probe spectroscopy revealed the collective effect of hot electron transfer as well as trap-state mediated electron delocalization in the enhanced photocatalytic H-2 evolution. This work reveals the role of photogenerated carriers in the photocatalytic performance of the CN/ZIS heterostructure and would create a new avenue toward the advancement of CN based heterostructure in photocatalytic devices.

Automated summary

A g-C3N4(CN)/ZnIn2S4 (ZIS) heterostructure was synthesized and a direct correlation between excited-state charge carrier dynamics and enhanced photocatalytic activity was established using ultrafast transient absorption (TA) spectroscopy. The study showed the dominance of hot electron transfer and the migration of photogenerated hot electrons from CN towards ZIS, contributing to enhanced photocatalytic H-2 evolution. This work highlights the potential of CN/ZIS heterostructures in improving photocatalytic performance and presents a new pathway for advancing photocatalytic devices.