Modulation of internal electric field engineering of bifunctional multi-interfacial heterojunction photocatalysts for photocatalytic H2 and H2O2 production

The purposeful construction of dual Z-scheme system to the formation of intimate interface contact and multi-channel charge flow through the system remains a huge challenge. Herein, a tandem 2D/0D/2D g-C3N4 nanosheets/FeOOH quantum dots/ZnIn2S4 nanosheets (CNFeZn) dual Z-scheme system (DZSS) has been successfully constructed using electrostatic self-assembly method. Owing to the band structure and elaborate morphology of 2D g-C3N4, 0D FeOOH and 2D ZnIn2S4 in unique designed DZSS, plenty of spatial charge transfer channels are formed between the g-C3N4/FeOOH and FeOOH/ZnIn2S4 interfaces, which greatly accelerate the charge separation and transfer. As bifunctional catalysts, CNFeZn DZSS achieves the highest H2 evolution rate of ∼436.6 μmol/h with a great promotion of ∼10.6 folds and ∼6.9 folds compared to pristine g-C3N4 and ZnIn2S4, respectively. Meanwhile, the H2O2 production rate reached ∼301.19 μM after 60 min irradiation, up to ∼5.1 times and ∼2.3 times that of pristine g-C3N4 and ZnIn2S4. Experiment and DFT calculation further confirmed that the stable double built-in electronic field can be formed owing to the electron configuration between double interfaces, and reveal that the ample atomic-level charge transfer channels were established in the strong interaction connected double interfaces, which can act as the charge migration pathway promote the separation of photogenerated charges.