Topology- and wavelength-governed CO<sub>2</sub> reduction photocatalysis in molecular catalyst-metal–organic framework assemblies

Stanley, Philip M.; Hemmer, Karina; Hegelmann, Markus; Schulz, Annika; Park, Mihyun; Elsner, Martin; Cokoja, Mirza; Warnan, Julien

doi:10.1039/d2sc03097g

Cited by 18 publications

(19 citation statements)

References 79 publications

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“…For H 2 BDC, ε ∼ 3 M –1 cm –1 at 390 nm (where the absorption and fluorescence curves cross and therefore being the highest point in the J spectral overlap integral, eq ), which is negligible. For example, porphyrin-based MOFs have a strong tendency to promote ultrafast exciton energy migrations, ,,,− which is consistent with large ε values in its lowest energy Q-bands (in the order of 10 4 M –1 cm –1 ) and consequently their large J integrals . Concurrently, H 4 BTTB exhibits an ε value of ∼327 M –1 cm –1 at 410 nm, which is also not very large.…”

Section: Resultsmentioning

confidence: 68%

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn₂(BTTB)(DMF)₂•(H₂O)₃]_n

Schlachter,

Asselin,

Fortin

et al. 2023

Inorg. Chem.

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3D-[Zn4O(1,4-BDC)3•x(solvent)] n (MOF-5; BDC = 1,4-benzodicarboxylate) and 3D-[Zn2(BTTB)(DMF)2•(H2O)3] n (MOF-D; BTTB = 4,4′,4″,4‴-benzene-1,2,4,5-tetrayltetrabenzoate) have been investigated by means of steady-state UV–visible and fluorescence and time-resolved emission spectroscopy, as a function of solvent and power of the excitation irradiation. The low-temperature X-ray structures (173 K) were permitted to locate solvent molecules (here H2O) in the lattice. They were found distributed in the middle in the voids with no evidence of specific interactions (H-bond, coulombic, and dipole–dipole) with the framework. The fluorescence decays of the ligands (ππ* excited state), τF, for the host–guest composites MOF-5@solvent and MOF-D@solvent (solvent = air, MeCN, EtCN, MeOH, EtOH, and DMF) were found bi-exponential (short τF1 (ps), and long τF2 (ns)) with one important feature: upon cooling from 298 to 77 K, MOF-5’s τF1 decreases and τF2 increases, while the opposite trend is generally observed in MOF-D. The low values for τF1 (ps) in MOF-5 are associated with the augmented probability of solvent-ligand collisions leading to nonradiative deactivation, which upon cooling to 77 K increases further as the scaffolding contracts. The augmentation in τF2 is readily associated with the increased rigidity of the ligands that are not submitted to this effect (at the surface of the MOF and as pendent groups). For the low emitter MOF-D, the reversed situation is noted but not as clearly due to the uncertainties in the data. Upon increasing the excitation flux, the fluorescence intensity increases linearly with the laser power indicating the absence of singlet–singlet annihilation, inferring the absence of efficient exciton migration. This observation is explained by the small absorptivity coefficients, which leads to a small J spectral overlap between absorption and fluorescence according to the Forster and Dexter theories, and consequently, a small rate for energy migration. This conclusion drastically changes the perception of the photocatalytic mechanism of MOF-5 and other MOFs exhibiting similar absorption features (i.e., no antenna effect).

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Section: Resultsmentioning

confidence: 68%

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn₂(BTTB)(DMF)₂•(H₂O)₃]_n

Schlachter,

Asselin,

Fortin

et al. 2023

Inorg. Chem.

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“…Nevertheless, catalytically active sites can be generated by designing molecular catalyst-metal-organic framework assemblies . Heterogenization of molecular catalysts on MOF generally includes the immobilization of porphyrin-based complexes, pyridine-based complexes, and Schiff base complexes using covalent interaction or noncovalent interactions. Schiff base ligands can incorporate catalytically active metals in a diverse range of oxidation states [e.g., Au(III), Pd(II), Mn(II), Fe(III), Co(II), and Ru(III)] into MOFs by postsynthetic modification. − This strategy can enhance the kinetics of the charge-separated carriers and the lifetime of the photoexcited electrons, thus promoting the activity and selectivity of photocatalytic reactions. , It is significant to note that most Schiff base compounds are polycyclic compounds or long-chain compounds with complex structures .…”

Section: Introductionmentioning

confidence: 99%

“…23 Nevertheless, catalytically active sites can be generated by designing molecular catalyst-metalorganic framework assemblies. 24 Heterogenization of molecular catalysts on MOF generally includes the immobilization of porphyrin-based complexes, 25 pyridine-based complexes, 26 and Schiff base complexes 27 using covalent interaction or noncovalent interactions. Schiff base ligands can incorporate catalytically active metals in a diverse range of oxidation states [e.g., Au(III), Pd(II), Mn(II), Fe(III), Co(II), and Ru(III)] into MOFs by postsynthetic modification.…”

Section: ■ Introductionmentioning

confidence: 99%

Immobilizing Isatin-Schiff Base Complexes in NH₂-UiO-66 for Highly Photocatalytic CO₂ Reduction

et al. 2023

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Reducing carbon dioxide (CO 2 ) via photocatalysis to carbon-based materials is a challenging process due to the complexity of the process and the production of several byproducts. Therefore, it is crucial to develop photocatalysts with high yield and selectivity for CO 2 reduction. Herein, we present a strategy for creating high-performance catalysts by immobilizing Ni, Co, and Cu ions in NH 2 -UiO-66 by covalently linking the isatin-Schiff base metal complexes (IS) to the micropores. The as-synthesized NH 2 -UiO-66/IS-complex (66-IS-M, M = Ni, Co, Cu) photocatalysts exhibit special photocatalytic activity for the reduction of CO 2 because of the immobilized metal ions serving as active sites during the reaction. Among them, 66-IS-Ni has a maximum CO generation rate of 1350 μmol g −1 h −1 and a CO selectivity of 87%, both of which are significantly higher than those of previously reported metal−organic framework (MOF)-based photocatalysts. Experimental characterizations and density functional theory (DFT) calculations reveal that the effective charge separation and lowered free energy of CO 2 reduction on 66-IS-Ni promote CO 2 conversion. This study presents a universal strategy for the uniform dispersion of molecular catalysts in amino-functionalized MOF for efficient photocatalytic applications.

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“…45 In this case, the molecular properties of porphyrin linkers could be solely discussed, since the Zr 6 O 8 cluster was reductively inert due to the high valence of Zr(IV). 46,47 The light-enhanced Au recovery process was studied with respect to performance tests, structural and compositional characterization, and elucidation of the effect of the electron donor and electron transfer pathway mechanism. We also demonstrated the cycling application of PCN-224 and its light-enhanced feature in an actual leaching solution of WEEE.…”

Section: ■ Introductionmentioning

confidence: 99%

Selective and Light-Enhanced Au(III) Recovery by a Porphyrin-Based Metal–Organic Framework: Performance and Underlying Mechanisms

et al. 2023

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Recovering gold from unconventional sources, such as electronic waste, offers significant environmental and economic benefits. Exploiting materials and methods with high efficiency and selectivity is demanding. Herein, we reported a novel light-enhanced Au(III) recovery process using a porphyrin-based metal–organic framework (PCN-224). Our results showed that PCN-224 exhibited a remarkable Au(III) recovery capacity of up to 2613 mg/g when exposed to visible light irradiation, which was 3 times higher than that in the dark. Furthermore, light irradiation also improved the Au selectivity of PCN-224 against coexisting ions, including Zn2+, Mg2+, Cd2+, Ni2+, Hg2+, Cu2+, Pb2+, Al3+, and Fe3+. Based on characterization and kinetic analysis, an adsorption–reduction mechanism was proposed for the light-enhanced Au recovery, and porphyrin linkers played an essential role as active sites for both adsorption and reduction. To further protect the porphyrin linkers in PCN-224, acetic acid was introduced as a representative electron donor molecule in electronic waste, which could further enhance the Au(III) recovery capacity to 4946 mg/g. In addition, we demonstrated that PCN-224 and its light-enhanced feature also performed effectively in the actual leaching solution of waste electrical and electronic equipment, and the framework was successfully reused for at least six cycles. Overall, our discoveries could inspire the design of more outstanding materials and the artful use of clean energy to recover precious metals while minimizing the environmental impact.

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Topology- and wavelength-governed CO₂ reduction photocatalysis in molecular catalyst-metal–organic framework assemblies

Abstract: Optimising catalyst materials for visible light-driven fuel production requires understanding complex and intertwined processes including light absorption, catalyst stability, as well as mass, charge, and energy transport. These phenomena can...

Cited by 18 publications

References 79 publications

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn₂(BTTB)(DMF)₂•(H₂O)₃]_n

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn₂(BTTB)(DMF)₂•(H₂O)₃]_n

Immobilizing Isatin-Schiff Base Complexes in NH₂-UiO-66 for Highly Photocatalytic CO₂ Reduction

Selective and Light-Enhanced Au(III) Recovery by a Porphyrin-Based Metal–Organic Framework: Performance and Underlying Mechanisms

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Topology- and wavelength-governed CO2 reduction photocatalysis in molecular catalyst-metal–organic framework assemblies

Abstract: Optimising catalyst materials for visible light-driven fuel production requires understanding complex and intertwined processes including light absorption, catalyst stability, as well as mass, charge, and energy transport. These phenomena can...

Cited by 18 publications

References 79 publications

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn2(BTTB)(DMF)2•(H2O)3]n

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn2(BTTB)(DMF)2•(H2O)3]n

Immobilizing Isatin-Schiff Base Complexes in NH2-UiO-66 for Highly Photocatalytic CO2 Reduction

Selective and Light-Enhanced Au(III) Recovery by a Porphyrin-Based Metal–Organic Framework: Performance and Underlying Mechanisms

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Product

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Topology- and wavelength-governed CO₂ reduction photocatalysis in molecular catalyst-metal–organic framework assemblies

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn₂(BTTB)(DMF)₂•(H₂O)₃]_n

Strong Host–Guest Dependence on the Emissive Properties of MOF-5 and [Zn₂(BTTB)(DMF)₂•(H₂O)₃]_n

Immobilizing Isatin-Schiff Base Complexes in NH₂-UiO-66 for Highly Photocatalytic CO₂ Reduction