A hybrid MOFs/Ti-Fe2O3 Z-scheme photoanode with enhanced charge separation and transfer for efficient photoelectrochemical water oxidation.

[Display omitted] • A novel Z-scheme NH 2 -MIL-125(Ti)/Ti-Fe 2 O 3 photoanode is designed and constructed. • NH 2 -MIL-125(Ti)/Ti-Fe 2 O 3 shows excellent PEC performance and stability. • The Z-scheme pathway is identified by surface photovoltage, ESR and fs-TAS. • Efficient separation of interface and surface carriers is simultaneously realized. The construction of Z-scheme charge transfer pathways simulating natural photosynthesis is considered a promising method for improving reaction driving forces. Here, we modified the surface of titanium doped Fe 2 O 3 (Ti-Fe 2 O 3) nanorods with NH 2 -MIL-125(Ti) (Ti-MOFs) and a promising organic-inorganic hybrid Z-scheme NH 2 -MIL-125(Ti)/Ti-Fe 2 O 3 was successfully prepared. At 1.23 V vs. RHE, the photocurrent density of the composite photoanode reaches 2.67 mA/cm2, which is 5 times higher than that of Ti-Fe 2 O 3. The results of surface photovoltage, ESR and fs-TAS indicate that this improvement is mainly due to the effective Z-scheme charge transfer mechanism providing a strong driving force for charge separation and transport, greatly suppressing carrier recombination and allowing carriers with strong oxidation ability to participate in water oxidation. Meanwhile, NH 2 -MIL-125(Ti) can enhance light absorption and reduce the surface defect state of Ti-Fe 2 O 3. This study not only provides a feasible approach for the photoanode water splitting of traditional inorganic semiconductor/MOF based heterostructures, but also provides rich and effective means for revealing Z-scheme charge transfer mechanism in depth. [ABSTRACT FROM AUTHOR]