Three-dimensional metal-intercalated covalent organic frameworks for near-ambient energy storage

Abstract

A new form of nanoporous material, metal intercalated covalent organic framework (MCOF) is proposed and its energy storage property revealed. Employing density functional and thermodynamical analysis, we find that stable, chemically active, porous materials could form by stacking covalent organic framework (COF) layers with metals as a gluing agent. Metal acts as active sites, while its aggregation is suppressed by a binding energy significantly larger than the corresponding cohesive energy of bulk metals. Two important parameters, metal binding and metal-metal separation, are tuned by selecting suitable building blocks and linkers when constructing COF layers. Systematic searches among a variety of elements and organic molecules identify Ca-intercalated COF with diphenylethyne units as optimal material for H2 storage, reaching a striking gravimetric density ~ 5 wt% at near-ambient conditions (300 K, 20 bar), in comparison to < 0.1 wt% for bare COF-1 under the same condition.

Tunable Water and CO2 Sorption Properties in Isostructural Azine-Based Covalent Organic Frameworks through Polarity Engineering

“…In addition, we chemically modified the channels by means of metal-doping, which had been predicted earlier to enhance gas sorption capacities and selectivities. [22][23][24][25] Therefore, AB-COF and ATFG-COF were loaded with either lithium or zinc acetate (LiOAc × 2 H 2 O and Zn(OAc) 2 × 2 H 2 O) by dissolving the salts in methanol and then adding the COF (see ESI for details). After soaking and washing, Li@AB-COF/Li@ATFG-COF and Zn@AB-COF/Zn@ATFG-COF were obtained, which showed metal loadings of 8% (with respect to all available coordination sites, see ESI for details) for Zn@ATFG-COF, 1% for Li@ATFG-COF, 0.6% for Zn@AB-COF, and 0.8% for Li@AB-COF.…”

“…However, metal ions were never successfully integrated in COFs postsynthetically. [22][23][24][25][26] It has been shown that doping with metal salts in MOFs can have a significant impact on gas uptakes, especially for CO 2 and H 2 sorption. [27][28][29][30] Here, we present two isostructural microporous COFsan azine-benzene-COF (AB-COF) and azine-triformylphloroglucinol-COF (ATFG-COF) based on a water-stable azine linkage -and develop a versatile COF platform combining the key features for both CO 2 capture and water sorption, namely (i) high CO 2 uptake capacity, (ii) tunable polarity, and (iii) gated water-uptake at low relative humidity.…”

Low‐Overpotential Electrocatalytic Water Splitting with Noble‐Metal‐Free Nanoparticles Supported in a sp3 N‐Rich Flexible COF

“…Only recently, COFs have been explored as supports for metal nanoparticles (NPs), which have resulted in composites with diverse properties . Through appropriate choice of building units, one can potentially tune the NP binding and NP–NP separation in the host COFs …”

Dynamisch‐kovalente Chemie

“…In‐silico‐Studien weisen darauf hin, dass die Interkalation von Alkali‐ oder Erdalkalimetallen in kovalenten Netzwerken die Wasserstoffaufnahme deutlich steigern kann. 5,6…”