Traditional MOF e‐CRR, constructed from catalytic linkers, manifest a kinetic bottleneck during their multi‐electron activation. Decoupling catalysis and charge transport can address such issues. Here, we build two MOF/e‐CRR systems, CoPc@NU‐1000 and TPP(Co)@NU‐1000, by installing cobalt metalated phthalocyanine and tetraphenylporphyrin electrocatalysts within the redox active NU‐1000 MOF. For CoPc@NU‐1000, the e‐CRR responsive CoI/0potential is close to that of NU‐1000 reduction compared to the TPP(Co)@NU‐1000. Efficient charge delivery, defined by a higher diffusion (
Charge‐separated metal–organic frameworks (MOFs) are a unique class of MOFs that can possess added properties originating from the exposed ionic species. A new charge‐separated MOF, namely, UNM‐6 synthesized from a tetrahedral borate ligand and Co2+cation is reported herein. UNM‐6 crystalizes into the highly symmetric
- NSF-PAR ID:
- 10256340
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 26
- Issue:
- 61
- ISSN:
- 0947-6539
- Page Range / eLocation ID:
- p. 13788-13791
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract D hop=4.1×10−12 cm2 s−1) and low charge‐transport resistance (=59.5 Ω) in CoPC@NU‐1000 led FECO=80 %. In contrast, TPP(Co)@NU‐1000 fared a poor FECO=24 % ( D hop=1.4×10−12 cm2 s−1and=91.4 Ω). For such a decoupling strategy, careful choice of the host framework is critical in pairing up with the underlying electrochemical properties of the catalysts to facilitate the charge delivery for its activation. -
Abstract Traditional MOF e‐CRR, constructed from catalytic linkers, manifest a kinetic bottleneck during their multi‐electron activation. Decoupling catalysis and charge transport can address such issues. Here, we build two MOF/e‐CRR systems, CoPc@NU‐1000 and TPP(Co)@NU‐1000, by installing cobalt metalated phthalocyanine and tetraphenylporphyrin electrocatalysts within the redox active NU‐1000 MOF. For CoPc@NU‐1000, the e‐CRR responsive CoI/0potential is close to that of NU‐1000 reduction compared to the TPP(Co)@NU‐1000. Efficient charge delivery, defined by a higher diffusion (
D hop=4.1×10−12 cm2 s−1) and low charge‐transport resistance (=59.5 Ω) in CoPC@NU‐1000 led FECO=80 %. In contrast, TPP(Co)@NU‐1000 fared a poor FECO=24 % ( D hop=1.4×10−12 cm2 s−1and=91.4 Ω). For such a decoupling strategy, careful choice of the host framework is critical in pairing up with the underlying electrochemical properties of the catalysts to facilitate the charge delivery for its activation. -
Abstract Metal–organic frameworks (MOFs) are promising materials for electrocatalysis; however, lack of electrical conductivity in the majority of existing MOFs limits their effective utilization in the field. Herein, an excellent catalytic activity of a 2D copper (Cu)‐based conductive MOF, copper tetrahydroxyquinone (CuTHQ), is reported for aqueous CO2reduction reaction (CO2RR) at low overpotentials. It is revealed that CuTHQ nanoflakes (NFs) with an average lateral size of 140 nm exhibit a negligible overpotential of 16 mV for the activation of this reaction, a high current density of ≈173 mA cm−2at −0.45 V versus RHE, an average Faradaic efficiency (F.E.) of ≈91% toward CO production, and a remarkable turnover frequency as high as ≈20.82 s−1. In the low overpotential range, the obtained CO formation current density is more than 35 and 25 times higher compared to state‐of‐the‐art MOF and MOF‐derived catalysts, respectively. The operando Cu K‐edge X‐ray absorption near edge spectroscopy and density functional theory calculations reveal the existence of reduced Cu (Cu+) during CO2RR which reversibly returns to Cu2+after the reaction. The outstanding CO2catalytic functionality of conductive MOFs (c‐MOFs) can open a way toward high‐energy‐density electrochemical systems.
-
Abstract Cooperative cluster metalation and ligand migration were performed on a Zr‐MOF, leading to the isolation of unique bimetallic MOFs based on decanuclear Zr6M4(M=Ni, Co) clusters. The M2+reacts with the μ3‐OH and terminal H2O ligands on an 8‐connected [Zr6O4(OH)8(H2O)4] cluster to form a bimetallic [Zr6M4O8(OH)8(H2O)8] cluster. Along with the metalation of Zr6cluster, ligand migration is observed in which a Zr–carboxylate bond dissociates to form a M–carboxylate bond. Single‐crystal to single‐crystal transformation is realized so that snapshots for cooperative cluster metalation and ligand migration processes are captured by successive single‐crystal X‐ray structures. In3+was metalated into the same Zr‐MOF which showed excellent catalytic activity in the acetaldehyde cyclotrimerization reaction. This work not only provides a powerful tool to functionalize Zr‐MOFs with other metals, but also structurally elucidates the formation mechanism of the resulting heterometallic MOFs.
-
Abstract A bimetallic hydroxychalcogenide, BaZn2Se2(OH)2, was synthesized through hydrothermal pouch methods. The single crystal X‐ray diffraction and electron diffraction indicates that the phase crystallizes in the orthorhombic space group
Pnma and is composed of anionic layers [ZnSe3/3(OH)1/1]−that are separated and charged balanced by Ba2+cations. The [ZnSe3/3(OH)1/1]–layer comprises two unique Zn sites, which form interpenetrating zigzag chains with an in‐plane dipole moment and adopts a brownmillerite‐type structural motif. The adjacent layers contain tetrahedrally coordinated Zn chains of opposite handedness related by an inversion center, which cancel the microscopic dipoles to minimize the macroscopic electric polarization. The adoption of a brownmillerite structural motif in BaZn2Se2(OH)2can be rationalized by the distinct charge difference between Se2−and OH−anions, which creates a sufficient dipole moment in the ZnSe3(OH) tetrahedra to allow the occurrence of twisted chains. FTIR spectroscopy confirms the existence of OH−anions and DFT calculations indicate that BaZn2Se2(OH)2is a semiconductor with a direct band gap. This work expands the chemistry of the brownmillerite family from traditional homoanionic oxides to multianion hydroxychalcogenides, offering a new opportunity to explore tunable structural complexity for better design of functional materials.