Electrochemically Triggered Dynamics within a Hybrid Metal–Organic Electrocatalyst

Abstract

A wide array of systems, ranging from enzymes to synthetic catalysts, exert adaptive motifs to maximize their functionality. In a related manner, select metal-organic frameworks (MOFs) and related systems exhibit structural modulations under stimuli such as the infiltration of guest species. Probing their responsive behavior in-situ is a challenging but important step towards understanding their function and subsequently building from there. In this report, we investigate the dynamic behavior of an electrocatalytic Mn-porphyrin containing MOF system (Mn-MOF). We discover, using a combination of electrochemistry and in-situ probes of UV-Vis absorption, resonance Raman and infrared spectroscopy, a restructuration of this system via a reversible cleavage of the porphyrin carboxylate ligands under an applied voltage. We further show, by combining experimental data and DFT calculations, as a proof of concept, the capacity to utilize the Mn-MOF for electrochemical CO2 fixation and to spectroscopically capture the reaction intermediates in its catalytic cycle. The findings of this work and methodology developed opens opportunities in the application of MOFs as dynamic, enzyme-inspired electrocatalytic systems.

Alkali‐induced Transformation of Ni‐MOF into Ni(OH)2 Nanostructured Flowers for Efficient Electrocatalytic Methanol Oxidation Reaction

“…Metal‐organic frameworks (MOFs) with the features of ultrahigh surface areas, large porosity, remarkable tailorability and tunable functionality, as well as the special physiochemical properties contributed to their application potentials in various fields over the past decades [1–7] . Especially, the facile accessibility of catalytic intermediates into periodically dispersed transition metals as the active sites throughout the frameworks promoted transition metal‐based MOFs as advanced electrocatalysts for different electrocatalytic reactions, as proposed and realized by previous researches [8–18] . However, the fragile coordination bonds between metals and organic ligands and poor conductivity in some MOFs are still hindering their broader applications in electrocatalysis [3,19–23] .…”

“…[1][2][3][4][5][6][7] Especially, the facile accessibility of catalytic intermediates into periodically dispersed transition metals as the active sites throughout the frameworks promoted transition metal-based MOFs as advanced electrocatalysts for different electrocatalytic reactions, as proposed and realized by previous researches. [8][9][10][11][12][13][14][15][16][17][18] However, the fragile coordination bonds between metals and organic ligands and poor conductivity in some MOFs are still hindering their broader applications in electrocatalysis. [3,[19][20][21][22][23] To further improve the electrocatalytic performance of MOF-based catalysts, various post-treatment strategies, such as high temperature annealing, solvothermal routes, and loaded with other components were explored recently.…”

Rational incorporation of defects within metal–organic frameworks generates highly active electrocatalytic sites

“…In regard to the tuning of the active site several strategies have been explored in recent years. Molecular catalysts serving as the organic linker within MOFs and COFs gave rise to several highly functional catalytic systems for the hydrogen evolution reaction (HER), 6,7 CO 2 reduction reaction (CO 2 R), [8][9][10][11][12] and oxygen reduction reaction (ORR). 13 The activity of the molecular active could be further tuned through electron withdrawing functional groups graed within the COF structures.…”

A photosensitive metal–organic framework having a flower-like structure for effective visible light-driven photodegradation of rhodamine B

“…17,18 In particular, the porphyrin-based MOFs have better photothermal stability, better photosensitivity and longlifetime excited states, and show excellent photoelectric performance, because the porphyrin molecule has large pconjugated structure with high rigidity and shows good electron mobility. At present, the porphyrin-based MOFs are widely used in photocatalysis 19 -for example, the photocatalytic reduction of CO 2 , [20][21][22] photocatalytic dye degradation, 15,17 photocatalytic hydrolysis producing H 2 , 23,24 and the photocatalysis of various organic reactions. 18,25,26 The morphology of MOFs is another important factor that can greatly affect their performance, especially in the eld of catalysis.…”