Developing post-modified Ce-MOF as a photocatalyst: a detail mechanistic insight into CO₂ reduction toward selective C2 product formation

Abstract

Visible light-driven C-C bond formation to produce C2-based liquid fuel selectively from CO2 is of great interest and remains a challenging task due to uphill electron transfer kinetics. Herein, we...

Pore-Confined π-Chromophoric Tetracene as a Visible Light Harvester toward MOF-Based Photocatalytic CO2 Reduction in Water

“…The average excited-state lifetime of TET in DMF was obtained as 4.33 ns, whereas Zr-MBA-TET-MOF displayed an enhanced lifetime of 12.79 ns. The increased lifetime when trapped inside the MOF indicates the confinement effect attributed to the nanospace provided by the MOF, which easily inhibits the collisional and diffusional relaxation, thus hindering the nonradiative decay pathway, thereby resulting in the significant enhancement in the lifetime. ,− …”

“…Metal–organic frameworks (MOFs), characterized by high surface areas, large pore sizes, and appreciable chemical, thermal, and mechanical stability, are extensively used for numerous applications, including gas storage, separation, optoelectronics, magnetism, heterogeneous catalysis, and so on. − MOFs have been recently explored for heterogenizing molecular catalysts and thereby effectively coordinating the advantages of both homogeneous and heterogeneous catalysis. , However, their poor visible light absorption characteristics often become a bottleneck for their application in artificial photosynthesis and photocatalysis. Integrating light-harvesting transition metal complexes, particularly Ir– and Ru–polypyridyl complexes, is well established and attributes the excellent light-harvesting property to otherwise feebly absorbing pristine MOFs. − In addition, inorganic semiconductors (e.g., TiO 2 ), plasmonic metal nanoparticles (e.g., Ag), and quantum dots (e.g., CsPbBr 3 ) are also incorporated with MOFs for enhancing their visible light absorption. − However, exploring the light-harvesting capability of the conjugated π-chromophoric class of molecules such as acene in photocatalytic reactions is yet to be investigated. Basically, acenes are a series of π-chromophoric polycyclic aromatic compounds comprising linearly fused benzene rings, which can possess highly intense absorption and emission properties and have attracted significant importance in the field of organic optoelectronic including the improvement in solar cell efficiency. − Moreover, these polyacenes, especially tetracene and pentacene, are known for possessing singlet fission due to their comparable energy level of the lowest singlet energy state and triplet pair .…”

Multifunctional Dysprosium(III)–Organic Framework for Efficiently Catalyzing the Cycloaddition of CO2 and Knoevenagel Condensation under Mild Conditions

“…Metal–organic frameworks (MOFs), as a kind of organic–inorganic crystalline hybrid materials self-assembled from organic ligands and metal nodes (ions or clusters) through coordination bonds, are extensively studied for their promising applications such as heterogeneous catalysis, targeting drug delivery, fluorescence probe, gas storage, and magnetism, − all of which can be controlled by regulating confined microenvironments, for instance, porosity, specific surface area, pore size, active site, and morphology. , For the past two decades, the strategic interlinkage between various metal-containing secondary building units (SBUs) and designed functional organic connectors under the guidance of the principle of reticular chemistry creates massive metal–organic topologies, among which the ones with coordinative unsaturation or open metal sites on metal SBUs are valued in the field of catalysis because the activated state with removing solvent molecules can serve as heterogeneous catalysts on a series of organic reactions, for instance, chemical fixation of CO 2 , Knoevenagel condensation, α-pinene oxide isomerization, aldehyde cyanosilylation, selective oxidation of organic chemicals, and citronellal cyclization. − However, recent studies confirm that MOFs without open metal sites also can act as Lewis acids because of the accessibility of the metal center to reactant molecules . Compared to the relatively large body of work done on the Lewis acidic MOFs, the attention on Brønsted acid sites has just begun . This should be due to that the activated acidic protons will interfere with the formation or stability of the skeleton .…”

“…10 Compared to the relatively large body of work done on the Lewis acidic MOFs, the attention on Brønsted acid sites has just begun. 11 This should be due to that the activated acidic protons will interfere with the formation or stability of the skeleton. 12 Furthermore, the properties of MOF materials are largely affected by their framework topologies, which determine the connectivity and size of channels and cavities.…”

A solvent-responsive terbium-organic framework for photocatalytic CO2reduction

“…15–17 Metal–organic framework (MOF) materials are considered to be ideal models for the study of photocatalytic reduction due to their large specific surface areas, abundance of active catalytic sites, the periodic distribution of the sites, and their unique electronic band structures. 18–20 In recent years, the application of MOF materials in the photocatalytic CO 2 reduction reaction (CO 2 RR) has attracted great attention. MOFs can directly act as photocatalysts for the CO 2 RR or as components that promote CO 2 reduction in complex photocatalytic systems.…”