Investigation of the preparation and reactivity of metal–organic frameworks of cerium and pyridine-2,4,6-tricarboxylate

Abstract

Crystallisation of three coordination polymers of Ce3+ and pyridine-2,4,6-tricarboxylate is possible with the material formed depending on solvent and time of reaction: one is hydrothermally stable and shows redox and photocatalytic properties.

Facile and efficient photocatalyst for degradation of chlortetracycline promoted by H2O2

“…On the one hand, H 2 O 2 can capture photogenerated electrons in the excited MOF-1 to generate ˙OH; on the other hand, Ce 3+ on the MOF-1 surface catalyzes the decomposition of H 2 O 2 to produce ˙OH (Ce 3+ + H 2 O 2 → Ce 4+ + ˙OH + OH − , Ce 4+ + H 2 O 2 → Ce 3+ + HO 2 ˙ + H + ), achieving significantly enhanced photocatalytic performance. 12,33 However, the removal performance of chlortetracycline was still unsatisfactory owing to the poor separation and migration of photogenerated electron–hole pairs. Interestingly, compared to the single ( MOF-1 , graphene oxide) or binary (GO/Fe 3 O 4 ) components, the 1 /GO/Fe 3 O 4 composite exhibited obviously superior degradation efficiency to chlortetracycline, with a removal rate of 80.5% in 180 minutes under visible light.…”

“…• + H + ), achieving significantly enhanced photocatalytic performance. 12,33 However, the removal performance of chlortetracycline was still unsatisfactory owing to the poor separation and migration of photogenerated electron-hole pairs. Interestingly, compared to the single (MOF-1, graphene oxide) or binary (GO/Fe 3 O 4 ) components, the 1/GO/Fe 3 O 4 composite exhibited obviously superior degradation efficiency to chlortetracycline, with a removal rate of 80.5% in 180 minutes under visible light.…”

Rapid synthesis of cerium-UiO-66 MOF nanoparticles for photocatalytic dye degradation

“…5 and Table S1a, b, † with the analysis based on previous interpretations in the literature. [56][57][58][59] The XPS spectra of Ce(IV) 3d 5/2 and 3d 3/2 regions for Ce-UiO-66-NH 2 are deconvoluted into six components and are assigned to Ce(IV) oxo-cluster formation, appearing between 884.6 and 917.3 eV. The signatures of Ce(III) 3d 5/2 and 3d 3/2 are observed between 882 and 911 eV.…”

Synthesis, Crystal Structure, and Photocatalytic Properties of Two Isoreticular Ce(IV)-MOFs with an Infinite Rod-Shaped Inorganic Building Unit

“…The incorporation of Ce­(IV) ions into MOFs enables the combination of redox activity with a large surface area and high availability of catalytically active sites. Thus, Ce­(IV)-MOFs have been used as catalysts for thermal and photochemical reactions. − The latter is facilitated by ligand-to-metal charge transfer (LMCT) of electrons to the energetically low-lying empty 4f orbital in Ce­(IV), which leads to charge separation and enables photooxidation of small molecules and photodegradation of dyes . The choice of linker is of fundamental importance for the LMCT process and for the photocatalytic activity of the system: the lowest-unoccupied molecular orbital (LUMO) energy level of the linker needs to be higher than the highest occupied molecular orbital (HOMO) energy level of Ce­(IV) ions to allow the electron transfer …”

“…8−11 The latter is facilitated by ligandto-metal charge transfer (LMCT) of electrons to the energetically low-lying empty 4f orbital in Ce(IV), which leads to charge separation 12 and enables photooxidation of small molecules 13 and photodegradation of dyes. 14 The choice of linker is of fundamental importance for the LMCT process and for the photocatalytic activity of the system: the lowestunoccupied molecular orbital (LUMO) energy level of the linker needs to be higher than the highest occupied molecular orbital (HOMO) energy level of Ce(IV) ions to allow the electron transfer. The first MOF containing exclusively Ce(IV) ions was Ce-UiO-66-BDC, BDC 2− = benzene-1,4-dicarboxylate, described by Lammert et al 15 in 2015, which is isostructural to the extensively studied Zr-UiO-66.…”