Study of the inorganic substitution in a functionalized UiO-66 metal–organic framework

Abstract

In this study the band gap modulation was studied in response to inorganic ion substitution within a thermally stable UiO-66 metal-organic framework (MOF). A combination of density functional theory prediction in conjunction with experimental predictions were used to map out the complete composition space for three inorganic ions (Zr, Ti, Hf) and three functional groups. The three functional groups include an amino group (NH2), a nitro group (NO2), and a hydrogenated case (H). The smallest band gap that experimentally determined was for a partially substituted UiO-66(Ti5Zr1)-NH2 resulting in 2.60 eV. Theoretical results indicated that Ti can be fully substituted within the lattice resulting in a predicted band gap as low as 1.62 eV. Modulation was a result of a mid-gap state introduced through the amino functionalization and HOMO shifting as a result of increased binding of the Ti-O-C bonds.

Missing Linkers: An Alternative Pathway to UiO-66 Electronic Structure Engineering

“…Also computationally, Ti materials have been shown to possess a much smaller Δ E LMCT . 77,79 Figure S6 shows our own calculations of UiO-66 with purely Ti, Zr, or Hf nodes. The low lying Ti 3d states overlap with the linker-based LUCO, increasing the electron transfer efficiency.…”

Unravelling Why and to What Extent the Topology of Similar Ce‐Based MOFs Conditions their Photodynamic: Relevance to Photocatalysis and Photonics

“…[8,[18][19][20][21] For example, for Zr-based MOFs, studies have elucidated the ultrafast dynamics related to excimer formation, ligand-to-cluster charge transfer (LCCT), and energy transfer to encapsulated guests. [18,[22][23][24][25] Other studies have explored the dynamics of Zr-based MOFs having the same linkers and metal clusters but different crystalline phases, and thus different distances and angles between their neighboring linkers. [26][27][28][29] These reports have shown the key role of the structural parameters in the interchromophoric interactions that lead to the formation of excimers in a specific network, and to their absence in others even having the same composition, but different structure.…”

Robust Ti‐ and Zr‐Based Metal‐Organic Frameworks for Photocatalysis

“…In addition to the above mentioned methods, several other strategies such as metal doping [106] and morphology control [107] were also reported for the optical property modulation. These methodologies provide significant insight for the rational design of MOFs with excellent light absorption properties and thus with desired photocatalytic activity.…”