Performance of ZIF-67 – Derived fold polyhedrons for enhanced photocatalytic hydrogen evolution

Abstract

Metal-organic framework (MOF) is one of the most promising precursors for the fabrication of advanced photo-semiconductors or cocatalysts due to its diverse structures and unique properties. However, the primitive MOF can not show greater potential and application value. Here Co-ZIF-67 dodecahedron was controllably carved via the different ways for efficiently boosting the photo-catalytic property of hydrogen evolution. This reasonable design can not only preserve polyhedron characteristics with the large specific surface area of ZIF-67, but also improve H2-evolution performance in Eosin Y sensitization system, which depends on the enhanced electronegativity of the surface of ZIF-6 derived polyhedrons and the quite strong adsorption of H and H2O by Co-site. Meanwhile, ligand group or hetero-atom adjacent to metal Co atom owing to the introduction of electronegative heteroatoms overturns the inherent structure and properties of ZIF-67 to a certain extent thereby rearranging the electron distribution and improving transfer efficiency of charge carriers. Additionally, the structural evolution of ZIF-67 constructs an efficient transport channels for migration of electron, which eliminates the resistance to be overcome when electrons migrate from the inside of a semiconductor to the surface. And the increase of optical absorption density caused by hyperchromicity effect is also a factor that can not be ignored for evolving the co-catalytic performance of ZIF-67.