Construction of covalently and coordination-linked MOF@COF heterojunctions via interfacial engineering for efficient photocatalytic hydrogen evolution

Constructing heterostructures serves as an effective strategy to address the low separation efficiency of photogenerated carriers in covalent organic frameworks (COFs). Herein, we leverage the structural features of TpBpy-COF bearing carbonyl and bipyridine moieties to fabricate covalently linked Zr-MOF-NH 2 @COF and coordination-linked Zr-MOF@COF via reactions with UiO-66-NH 2 and UiO-66, respectively. The findings reveal that both Zr-MOF-NH 2 @COF and Zr-MOF@COF exhibit excellent photocatalytic hydrogen evolution activity compared with the physically mixed Zr-MOF-NH 2 &COF and Zr-MOF&COF composites, owing to the formation of tightly interfaces. In particular, Zr-MOF-NH 2 @COF shows obviously improved hydrogen production performance. The optimal sample Zr-MOF–NH 2 –10@COF achieves an outstanding hydrogen production rate of 37.67 mmol g −1  h −1 , which is 1.3 times that of Zr-MOF@COF. The Zr-MOF-NH 2 @COF S-scheme heterojunction facilitates charge separation and boosts photocatalytic H 2 evolution. This work compares covalently and coordination-linked MOF@COF heterostructures to guide interfacial optimization of related photocatalysts.