Regulating Electronic Structure of Metal-Organic Frameworks for Improved Photocatalytic Activity Through Trace of Molecular Doping

Doping, introducing trace of impurity into a material to alter its original electrical or optical properties, constitutes the very basis for the great number of electronic devices pervaded in material sciences. Unfortunately, this strategy has yet to be applied in metal-organic frameworks (MOFs). In this study, we for the first time demonstrate that doping trace of organic molecules into MOFs dramatically alters the electric structure and optical property of the bulky material without disturbing the original frameworks as confirmed by both powder and single-crystal x-ray diffraction. This method is applicable to various dopants and other types of MOFs. Theoretical calculation suggested that the dopant introduces an impurity level in the host band structure, which greatly narrows the band gap and boosts the photogenerated electron-hole separation. Therefore, a photocatalytic inert MOFs can achieve excellent activity for water splitting though a trace of molecular doping. These findings presented here provide a powerful yet facile strategy toward regulating the electronic band structure of MOFs for improved catalytic activity without necessarily changing the original chemical components, topology, and porosity.