Tuning\nthe Optoelectronic Properties of Hybrid Functionalized\nMIL-125-NH₂ for Photocatalytic Hydrogen Evolution

Abstract

Metal–organic\nframeworks (MOFs) constructed with mixed ligands\nhave shown great promise in the generation of materials with improved\nsorption, optical, and electronic properties. With an experimental,\nspectroscopic, and computational approach, herein, we investigated\nhow the incorporation of different functionalized ligands within the\nstructure of MIL-125-NH₂ affects its performance in photocatalytic\nwater reduction. We found that multiligand incorporation within the\nMOF structure has an impact on the light absorption spectrum and the\nelectronic structure. These combined modifications improve the photocatalytic\nperformance of MIL-125-NH₂, thereby increasing the rate\nof hydrogen evolution reaction. Of the four nanoparticle/MOF photocatalytic\nsystems tested, we showed that the Pt/MIL-125-NH₂/(OH)₂ system (Pt nanoparticle plus MIL-125-NH₂ with\namino and dihydroxyl functionalized ligands) outperforms its counterpart\nPt/MIL-125-NH₂ system, attributed to the enhanced p−π\nconjugation between the lone pairs of O atoms and their aromatic ligands\nresulting in a red-shifted absorption spectrum and greater spatial\ndistribution of electron density.