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.

Automated summary

Metal Organic Frameworks (MOFs) with versatile chemical functionality and tunable pore structures are attractive for various applications. In this study, the doping of the Ti12O15 inorganic node of MIP-177(Ti) MOF with different transition metals (Fe, Ru, and Zr) is systematically explored using computational methods. The results show that the doping metals preferentially substitute the corner-sharing trimers of Ti octahedra, and the band gap can be significantly tuned by low concentrations of metal doping. This computational work is important for the development of mixed metal MOFs with controllable electronic properties for potential photocatalysis applications.