A systematic first-principles exploration of the impact of metal doping on the electronic properties of MOF MIP-177(Ti)

Metal Organic Frameworks offer an unprecedented versatility in terms of chemical functionality (metal nodes, organic linkers) and pore size/shape that make this family of porous materials attractive for many applications. Herein, a computational study based on periodic Density Functional Theory is conducted to systematically explore the doping of the Ti12O15 inorganic node of the microporous MIP-177(Ti) MOF by a series of transition metals including Fe, Ru and Zr. A first structural analysis revealed that all doping metals preferentially substitute the corner-sharing trimers of Ti octahedra. The band gap was further demonstrated to be highly tunable by a low concentration of metal doping with band gaps ranging from 3.18 eV (MIP-177(Ti/RuIV)) to 3.82 eV (MIP-177(Ti/FeIII)) vs 3.92 eV for the pristine MIP-177(Ti). This trend is explained in light of a careful analysis of the electronic properties of each doped system. This computational work is expected to pave the way towards the development of a platform of mixed metal MIP-177(Ti/M) with controllable electronic properties of utmost importance for potential applications of photocatalysis among others.