Asymmetrical facet-oriented anisotropic charge migration of MIL-101(Fe) with internal electric field-steered photogenerated holes for boosting photocatalytic oxidation

Abstract

Controllably steering the photogenerated charge behaviors of semiconductor photocatalysts is crucial in improving photocatalytic oxidation. By engineering the primary facet from (101) to (112), the asymmetrical feather of MIL-101(Fe)(112) result in potential difference on varied facets to contribute to anisotropic charge migration, which has been determined by the preferentially photodeposited cocatalysts on facet (112) and facet (119) of the nanocrystal. Thus-observed anisotropic charge migration of MIL-101(Fe)(112) contribute to 10 times stronger internal electric field (IEF) to accelerate charge separation and migration. Also, we demonstrate the lowest unoccupied crystal orbital (LUCO) of MIL-101(Fe)(112) deepened (up to 3.33 eV vs. NHE) and acquire 3.5 times higher photogenerated holes for robust hole oxidation capacities. As a proof-of-concept, the optimal MIL-101(Fe)(112) can acquire 100 % higher degradation rate and 33 % higher mineralization than MIL-101(Fe)(101). This work highlights the importance of unsymmetric facet manipulation in tailoring photocatalysts for efficient photocatalytic oxidation.