A Novel Cerium(IV)‐Based Metal‐Organic Framework for CO₂ Chemical Fixation and Photocatalytic Overall Water Splitting

Abstract

Cerium (IV)-based metal-organic frameworks (MOFs) are highly desirable due to their unique potential in fields such as redox catalysis and photocatalysis. However, due to the high reduction potential of Ce IV species in solution, it is still a great challenge to synthesize Ce IV -MOFs with novel structures, which are extremely dominated by the hexanuclear CeÀ O cluster inorganic building units (IBUs). Herein, a CeÀ O IBU chain containing Ce IV -MOF, CSUST-3 (CSUST: Changsha University of Science and Technology), was successfully prepared using the kinetic stabilization study of UiO-66(Ce)-NDC (H 2 NDC = 2,6naphthalenedicarboxylic acid). Furthermore, owing to the superior redox activity, Lewis acidity and semiconductor-like behavior owing to Ce 4 + , activated CSUST-3 was demonstrated to be an excellent catalyst for CO 2 chemical fixation. One-pot synthesis of styrene carbonate from styrene and CO 2 was achieved under mild conditions (1 atm CO 2 , 80 °C, and solvent free). Moreover, activated CSUST-3 was shown to be a remarkable co-catalyst-free photocatalyst for overall water splitting (OWS), rendering 59 μmol g À 1 h À 1 of H 2 and 22 μmol g À 1 h À 1 of O 2 under simulated sunlight irradiation (Na 2 S-Na 2 SO 3 as sacrificial agent).

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

“…The results from the TG analyses and VT-PXRD measurements also confirm the high thermal stability of >290 °C for both MOFs that exceeds the one for most Ce­(IV)-MOFs featuring the hexanuclear cluster. ,, However, it is similar to the decomposition temperatures observed for MOFs with infinite rod-shaped IBUs such as CSUST-3 (350 °C) and MIL-140 (310–370 °C). , This observation supports the assumption that the high thermal stability is directly linked to the existence of an infinite rod-shaped IBU in Ce­(IV)-MOF structures.…”

“…Examples include Ce­(IV)-MOFs with the MIL-140 structure, first reported by D′ Amato et al, which are isostructural to Zr-MIL-140 ([ZrO­(BDC)]) . The other example is CSUST-3, [Ce 2 O­(NDC) 3 (DMF) 2 ]·DMF (NDC 2– = 2,6-naphthalenedicarboxylate), which was observed as a metastable intermediate during the decomposition of Ce-UiO-66-NDC to Ce­(III) formate . The MIL-140 compounds are accessible with various linear linker molecules and replacement of DMF as the solvent by water or acetonitrile .…”

Lead-Decorated Titanium Oxide Compound with a High Performance in Catalytic CO2 Insertion to Epoxides

“…On the basis of the preceding results and discussion, as well as the literature reports, ,− a plausible mechanism for the 1 -catalyzed cycloaddition reaction of CO 2 to an epoxide is shown in Scheme . Because 1 or TBAB cannot catalyze the reaction proficiently on their own, their coparticipation could be clearly established.…”

Cerium versus zirconium UiO66 metal–organic frameworks coupled with CdS for H2 evolution under visible light

“…Cerium-substituted MOFs are of special interest, because of the Ce 4+/3+ redox chemsitry. [14][15][16][17][18] Different from Zr-UiO-66, Ce-UiO-66 is not only stable in water, 19 but also absorbs light at wavelengths up to 500 nm. A theoretical calculation reveals that the unoccupied Zr 4d and Ce 4f orbitals are located above and below the unoccupied BDC orbitals, respectively.…”