Epitaxial growth of metal-organic framework nanosheets into single-crystalline orthogonal arrays

Abstract

Construction of two-dimensional nanosheets into three-dimensional regular structures facilitates the mass transfer and exploits the maximum potential of two-dimensional building blocks in applications such as catalysis. Here, we report the synthesis of metal-organic frameworks with an orthogonal nanosheet array. The assembly involves the epitaxial growth of single crystalline metal-organic framework nanosheets with a naturally non-preferred facet exposure as the shell on a cubic metal-organic framework as the core. The nanosheets, despite of two typical shapes and crystallographic orientations, also form a single crystalline orthogonally arrayed framework. The density and size of nanosheets in the core-shell-structured composite metal-organic frameworks can be well adjusted. Moreover, metal-organic frameworks with a single composition and hollow orthogonal nanosheet array morphology can be obtained. Benefiting from the unusual facet exposure and macroporous structure, the designed structure exhibits improved electrocatalytic oxygen evolution activity compared to conventional nanosheets.

Understanding the Role of Titanium Metal–Organic Framework Nanosheets in Modulating Anode Chemistry for Aqueous Zinc-Ion Batteries

“…NH 2 -MIL-125 (Ti) with a typical aperture size of 5–7 Å (pore window), tunable morphologies, and moderate water stability by hydrophilic titanium–oxo–hydroxo clusters and amino groups − is selected as a model of a Zn 2+ sieve. The two-dimensional (2D) NS structure affords a high surface to volume ratio with enhanced surface exposure and a close stack for efficient desolvation, which ensures improved mass transfer and shortened ionic pathways for Zn 2+ transport, , where the 2D architecture is reported to promote uniform zinc deposition. ,, First-principles calculations revealed the crucial role of the Ti MOF in the dehydration of Zn 2+ and the decrease in HER reactivity. Consequently, the Ti MOF NSs-protected Zn anode delivered greatly improved cycling stability with a low degree of polarization in symmetric cells (2800 cycles at 20 mA cm –2 ) and improved cycling performance in Zn||MnO 2 full cells.…”