Band gap modulation in zirconium-based metal–organic frameworks by defect engineering

Abstract

A simple defect engineering approach to systematically tune the band gap of the prototypical zirconium-based metal–organic framework UiO-66 is reported. Defect engineered materials display enhanced photocatalytic activity.

Building MOF Nanocomposites with Oxidized Graphitic Carbon Nitride Nanospheres: The Effect of Framework Geometry on the Structural Heterogeneity

“…For UiO66, absorption occurs in the ultraviolent range, up to 315 nm (~4 eV). Taddei and co-workers reported the band gap of this MOF as 4.1 eV (302 nm) [28] and showed that the defect engineering of UIO-66 based on modulated synthesis or post-synthetic linker exchange led to a decrease in the optical band gap. In the case of UiO66-C, the light absorption starting at 400 nm (3.1 eV) supports the decrease in the band gap compared to the pure UiO66.…”

“…The diversity of the metal centers and organic ligands leads to materials of particular crystallographic structure, texture, and chemistry. Due to these properties, MOFs have been tested for various applications such as gas separation/storage [4][5][6][7][8][9], purification [10][11][12], sensing [13][14][15][16], electrodes for batteries [17,18], microextraction [19,20], detoxification of chemical warfare agents [21][22][23][24][25], and heterogeneous catalysis [26][27][28].…”

“…Therefore, the efforts have been intensified to introduce defects to the MOF structure targeting specific applications. Examples include mixed linkers [28][29][30], HCl treatment [31,32], variations in the synthesis conditions [33], the addition of molecular guests [34][35][36][37][38] or the incorporation of modified linkers [39,40]. These processes result in crystal imperfection, partial ligand replacement, or in nonbridging ligands, affecting the porosity, and the population, dispersion, and availability of active centers.The composites of MOFs with graphite oxide (GO) showed an increased pore volume, conductivity, and chemical heterogeneity [41][42][43].…”

Temperature modulation of defects in NH2-UiO-66(Zr) for photocatalytic CO2 reduction

“…Moreover, the study of defect engineering as the way to improve the photocatalytic performance of MOFs is still rare. 30,31 Herein, we wish to report a facile method to create defects in NH 2 -UiO-66(Zr). Via simply tuning the crystallization temperature, a series of defective NH 2 -UiO-66(Zr) samples were obtained in the present of hydrochloric acid as a modulator and then their photocatalytic activities in CO 2 reduction were also examined.…”

A Comprehensive Thermogravimetric Analysis Multifaceted Method for the Exact Determination of the Composition of Multifunctional Metal‐Organic Framework Materials

“…A common approach is to compare the theoretical mass decomposition steps for pristine and defective MOF structures to the experimental values to find matching structures. [64,65] Alternative methods calculate the mass per cent corresponding to each decomposition step to calculate the number of linkers and/or modulators, [32,58,63,66] but difficulty increases with multifunctionality and defectivity, with reports often providing qualitative TGA analysis or estimations of MOF composition. In fact, it is common to find comparisons between the experimental and theoretical thermal residues as a validation of MOF composition.…”