Rational Design of BODIPY Functionalized MOF Photocatalysts for Highly Efficient Hydrogen Production

Abstract

Photocatalytic hydrogen production through water reduction, supported by hydrogen with high energy density and environmental sustainability, exhibits a significant pathway for meeting the future energy needs, is considered one of the most promising strategies. A major challenge is developing a photocatalyst that is sustainable, stable, environmentally friendly, and large surface area. Although various MOF-based photocatalysts incorporating porphyrins, phthalocyanines, or other organic dyes have been extensively explored, studies utilizing BODIPY as a functional chromophore remain scarce. The combination of MOFs with BODIPY units offers a unique platform that couples the structural tunability and stability of MOFs with the excellent light-harvesting and electron-accepting properties of BODIPY dyes. However, systematic design and synthesis of BODIPY–MOF hybrid photocatalysts for hydrogen evolution are still very limited. Within the scope of the study, the UiO-66-NH2 structure was modified with BODIPY compounds containing Thiophene (BD2) and Phenyl (BD4) units, and BD2/UiO-66-NH2 and BD4/UiO-66-NH2 nanostructures were synthesized. As a result of the 6-hour photocatalytic water splitting experiments, the reaction kinetics of UiO-66-NH2, BD2/UiO-66-NH2, and BD4/UiO-66-NH2 were calculated as 3013 μmol g⁻¹ h⁻¹, 14237 μmol g⁻¹ h⁻¹(4.7-fold increase compared to UiO-66-NH2 ), and 21179 μmol g⁻¹ h⁻¹ (7-fold increase compared to UiO-66-NH2), respectively. Based on the band structure and photoelectrochemical results, the observed behavior is consistent with an S-scheme charge-transfer pathway for the photocatalytic process. This study provides a new insight into integrating BODIPY chromophores into MOF frameworks, establishing a promising design concept for the development of efficient dye–MOF hybrid photocatalysts for solar-to-hydrogen conversion.