BiFeO3-Based All Perovskite Oxides Direct Z-Scheme Heterostructure for Efficient Oxygen Evolution

BiFeO3 (BFO) has gained significant attentionrecentlyin photocatalytic water splitting due to its visible light activeprofile and facile synthesis design. However, a single component photocatalystusually suffers from significant photoexcited charge-carrier recombination.To overcome this problem, BFO nanocuboids are coupled with two-dimensionalCa(2)Nb(3)O(10) (CNO) nanosheets via afacile electrostatic self-assembly method. The surface charge of BFOnanocuboids is modulated via deposition of Co-nanoparticles to obtainedpositively charged BFO-Co nanocuboids. Resultantly, the combinationof positively charged BFO-Co nanocuboids and negative charged CNOnanosheets demonstrated a direct Z-scheme heterojunction. The optimizedBFO-Co/CNO heterostructure achieved outstanding photocatalytic O-2 evolution (48.19 mmol g(-1)), which is 6.72times higher than pristine BFO (7.17 mmol h(-1) g(-1)). Different characterization confirmed that BFO-Co/CNOheterostructures exhibited improved charge-carrier separation andutilization compared to individual components. This improved responsecan be associated with a better contact interface between the oppositelycharged surfaces with the added advantage of the perovskite natureof both components. As a result, BFO-Co/CNO heterostructures achievedthe highest O-2 evolution response for BFO-based heterostructuresto date. This study offers a novel strategy for modulating the BFOnanocuboids surface charge via Co-nanoparticles deposition, whichconcomitantly worked as a cocatalyst, a potential strategy that canbe applied for the design of various heterostructures.

Automated summary

This study successfully couples BiFeO3 nanocuboids with two-dimensional Ca(2)Nb(3)O(10) nanosheets to form a direct Z-scheme heterojunction, achieving efficient photocatalytic O-2 evolution. The improved response can be attributed to a better contact interface between the oppositely charged surfaces and the advantages of the perovskite nature of both components. By surface modification, this study provides a novel strategy to modulate the surface charge of BiFeO3 nanocuboids and achieves the highest O-2 evolution response among BiFeO3-based heterostructures to date.