Self-sacrificed construction of defect-rich ZnO@ZIF-8 nanocomposites with enhanced photocurrent properties

As an ideal candidate for photoanode materials, ZnO with various morphological and functional properties have been designed and synthesized for application in photoelectrochemical cells. However, the fast internal recombination between photocarriers greatly limits the separation efficiency of ZnO. In this situation, it is found that defects in metal-organic frameworks (MOFs) usually result in unique properties of composites of the MOFs. Here, we propose an in situ self-sacrificed system to fabricate ZnO@ZIF-8 nanocomposites with a large number of defective active sites. The induced uncoordinated N atoms interact with H₂O molecules to form hydrogen bonds and create proton pathways. The proton pathways gather large amounts of hydrogen ions, increase the electrolyte contact and inhibit the internal recombination between photocarriers. The improved performance may inspire the synthesis of ZnO-based photoanodes and provide important insight into the application of defect chemistry in MOFs.