Mechanistic Elucidations of Highly Dispersed Metalloporphyrin Metal‐Organic Framework Catalysts for CO₂Electroreduction

Abstract

Immobilization of porphyrin complexes into crystalline metal-organic frameworks (MOFs) enables high exposure of porphyrin active sites for CO 2 electroreduction. Herein, well-dispersed iron-porphyrin-based MOF (PCN-222(Fe)) on carbon-based electrodes revealed optimal turnover frequencies for CO 2 electroreduction to CO at 1 wt.% catalyst loading, beyond which the intrinsic catalyst activity declined due to CO 2 mass transport limitations. In situ Raman suggested that PCN-222(Fe) maintained its structure under electrochemical bias, permitting mechanistic investigations. These revealed a stepwise electron transfer-proton transfer mechanism for CO 2 electroreduction on PCN-222(Fe) electrodes, which followed a shift from a ratelimiting electron transfer to CO 2 mass transfer as the potential increased from À 0.6 V to À 1.0 V vs. RHE. Our results demonstrate how intrinsic catalytic investigations and in situ spectroscopy are needed to elucidate CO 2 electroreduction mechanisms on PCN-222(Fe) MOFs.

Sheet-on-sheet architectural assembly of MOF/graphene for high-stability NO sensing at room temperature

“…71,72 The characteristic peaks at 385 cm −1 and 1358 cm −1 were assigned to the Fe–N breathing mode and Fe–N bond of pyrrole deformation mode, respectively. 73 The peak at 392 cm −1 was attributed to the Co–O bond, indicating the formation of a Co 2 (COO) 4 paddlewheel structure, which was in accordance with XRD data. Additionally, the peaks of DLS-2D-Co-TCPP(Fe)/ANS–rGO presented all the typical peaks of ANS–rGO and DLS-2D-Co-TCPP(Fe).…”

Kinetic Impacts of Defect Sites in Metal–Organic Framework Catalysts under Varied Driving Forces

“…30 In these cases, the MOF acts as the active catalytic phase or as an auxiliary component that can utilize specific material properties (e.g., porosity or functional group proximity) to facilitate catalysis. 31 Conversely, MOFs can act as scaffolds that reconstruct under potential bias (or external extreme thermal bias), resulting in MOF-derived metal or metal composite materials (e.g., oxides, phosphides, sulfides, etc.) with unique architectures.…”