Comparative Studies on the Proton Conductivities of Hafnium-Based Metal–Organic Frameworks and Related Chitosan or Nafion Composite Membranes

Inorganic Chemistry, Journal Year: 2022, Volume and Issue: 61(25), P. 9564 - 9579

Published: June 14, 2022

Hafnium (Hf)-based UiO-66 series metal-organic frameworks (MOFs) have been widely studied on gas storage, separation, reduction reaction, and other aspects since they were first prepared in 2012, but there are few studies proton conductivity. In this work, one Hf-based MOF, Hf-UiO-66-fum showing structure, also known as MOF-801-Hf, was synthesized at room temperature using cheap fumaric acid the bridging ligand, then imidazole units successfully introduced into MOF-801-Hf to obatin a doped product, Im@MOF-801-Hf. Note that both Im@MOF-801-Hf demonstrate excellent thermal, water, acid-base stabilities. Expectedly, maximum conductivity (σ) of (1.46 × 10-2 S·cm-1) is nearly 4 times greater than (3.98 10-3 under 100 °C 98% relative humidity (RH). To explore their possible practical application value, we them chitosan (CS) or Nafion membranes fillers, namely, CS/MOF-801-Hf-X, CS/Im@MOF-801-Hf-Y, Nafion/MOF-801-Hf-Z (X, Y, Z doping percentages MOF membrane, respectively). Intriguingly, it found CS/MOF-801-Hf-6 CS/Im@MOF-801-Hf-4 indicated highest σ values 1.73 2.14 S·cm-1, respectively, RH Nafion/MOF-801-Hf-9 revealed high value 4.87 S·cm-1 80 RH, which showed varying degrees enhancement compared original MOFs pure CS membranes. Our study illustrates these related composite offer great potential electrochemical fields.

Language: Английский

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Recent Progress of Crystalline Porous Frameworks for Intermediate-Temperature Proton Conduction

Langmuir, Journal Year: 2023, Volume and Issue: 39(32), P. 11166 - 11187

Published: Aug. 3, 2023

Proton exchange membranes (PEMs), especially for work under intermediate temperatures (100–200 °C), have attracted great interest because of the high CO toleration and facial water management corresponding proton membrane fuel cells (PEMFCs). Traditional polymer PEMs faced challenges low stability carrier leaking. Crystalline porous materials, such as metal–organic frameworks (MOFs) covalent organic (COFs), are promising to overcome these issues contributed by nanometer-sized channels. Herein we summarized recent development MOF/COF-based intermediate-temperature conductors. The strategies framework engineering pore impregnation were introduced in detail raising conductivity. proton-conducting mechanism was described well. This spotlight will provide new insight into fabrication MOF/COF conductors anhydrous conditions.

Language: Английский

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The effect of free carboxylic acid groups on the proton conductivity of a series of UiO-66-Ce(IV) metal-organic frameworks

Microporous and Mesoporous Materials, Journal Year: 2023, Volume and Issue: 351, P. 112481 - 112481

Published: Feb. 3, 2023

Language: Английский

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Prominent Intrinsic Proton Conduction in Two Robust Zr/Hf Metal–Organic Frameworks Assembled by Bithiophene Dicarboxylate

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(23), P. 10786 - 10797

Published: May 21, 2024

To date, developing crystalline proton-conductive metal–organic frameworks (MOFs) with an inherent excellent proton-conducting ability and structural stability has been a critical priority in addressing the technologies required for sustainable development energy storage. Bearing this mind, multifunctional organic ligand, 3,4-dimethylthiophene[2,3-b]thiophene-2,5-dicarboxylic acid (H2DTD), was employed to generate two exceptionally stable three-dimensional porous Zr/Hf MOFs, [Zr6O4(OH)4(DTD)6]·5DMF·H2O (Zr-DTD) [Hf6O4(OH)4(DTD)6]·4DMF·H2O (Hf-DTD), using solvothermal means. The presence of Zr6 or Hf6 nodes, strong Zr/Hf–O bonds, electrical influence methyl group, steric effect thiophene unit all contribute their throughout wide pH range as well water. Their proton conductivity fully examined at various relative humidities (RHs) temperatures. Creating intricate rich H-bonded networks between guest water molecules, coordination solvent thiophene-S, –COOH, –OH units within framework assisted transfer. As result, both MOFs manifest maximum 0.67 × 10–2 4.85 10–3 S·cm–1 under 98% RH/100 °C, making them top-performing Zr/Hf-MOFs. Finally, by combining characteristics activation energies, potential conduction pathways were identified.

Language: Английский

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Synthesis of coordination compounds with 4′-(carboxymethoxy)-[1,1′-biphenyl]-4-carboxylate ligand and their catalytic activities towards the Knoevenagel condensation and cyanosilylation reactions

Journal of Saudi Chemical Society, Journal Year: 2024, Volume and Issue: 28(2), P. 101817 - 101817

Published: Jan. 29, 2024

Eight new transition-based coordination compounds were hydrothermally fabricated using metal chlorides (M = Co(II), Ni(II), Mn(II), Zn(II) and Cd(II)) with main ligand 4′-(carboxymethoxy)-[1,1′-biphenyl]-4-carboxylic acid (H2cbca) as well coligands (phen: 1,10-phenanthroline; 2,2′-bipy: 2,2′-bipyridine; 4,4′-bipy: 4,4′-bipyridine or dpe: 1,2-di(4-pyridyl)ethane). The successful synthesis obtained one 0D dimer, three 1D four 2D polymers, formulated [Cd(μ3-cbca)(H2O)]n (1), [Zn(μ-cbca)(phen)]n (2), [Mn(μ3-cbca)(phen)(H2O)]n (3), [Cd(μ3-cbca)(2,2′-bipy)]n (4), [Co(µ-cbca)(μ-4,4′-bipy)(H2O)2]n (5), [Co(μ3-cbca)2(μ-dpe)0.5(H2O)]n (6), [Ni2(cbca)2(μ-dpe)(H2O)8] (7), [Zn(μ3-cbca)(μ-dpe)0.5(H2O)]n (8). Comprehensive characterisations performed through standard methods. Topological types catalytic performance of these researched. Especially, polymer 2 serves a stable, highly effective, recyclable heterogeneous catalyst for the Knoevenagel condensation cyanosilylation benzaldehydes, giving high product yields (up to 100 %) under optimized conditions. Various reaction parameters, substrate scope, recycling also studied. present work explores application H2cbca flexible dicarboxylate linker preparation functional polymers.

Language: Английский

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