A S-Scheme MOF-on-MOF Heterostructure

Abstract

Constructing MOF-on-MOF heterojunction with elaborate charge transfer mechanism and interface is a promising strategy for improving the photocatalytic properties of MOFs. Herein, a Step-scheme (S-scheme) MIL-125-NH2@CoFe Prussian blue analogue (PBA) heterojunction is reported for the first time. The MOF-on-MOF heterostructure exhibits a sandwich-like morphology with hollow CoFe PBA nanocages selectively assembled on the top-down surfaces of MIL-125-NH2 nanocakes. Experimental findings and theoretical simulation results reveal the formation of internal electric field via interfacial Ti-O-Co bonds at the heterojunction, providing driving force and atomic transportation highway for accelerating the S-scheme charge transfer and enhancing the redox performance. Contributed further by the hollow sandwich-like structures with increased active site exposure, the designed MOF-on-MOF heterojunction exhibits significantly enhanced photocatalytic activity for degradation of various organic pollutants. This study provides insights toward the rational design of semiconducting MOF-based heterojunctions with improved properties.