A porous metal-organic framework with ultrahigh acetylene uptake capacity under ambient conditions

TL;DR

A new metal-organic framework called FJI-H8 can store large amounts of acetylene safely at room temperature and pressure.

Contribution

FJI-H8 achieves record-high acetylene uptake under ambient conditions using a unique combination of pore structure and open metal sites.

Findings

FJI-H8 has a gravimetric acetylene uptake of 224 cm³ (STP) g⁻¹ at 295 K and 1 atm.

The material retains over 96% of its storage capacity after five adsorption–desorption cycles.

Pore geometry and open metal sites are key to its high acetylene storage performance.

Abstract

Acetylene, an important petrochemical raw material, is very difficult to store safely under compression because of its highly explosive nature. Here we present a porous metal-organic framework named FJI-H8, with both suitable pore space and rich open metal sites, for efficient storage of acetylene under ambient conditions. Compared with existing reports, FJI-H8 shows a record-high gravimetric acetylene uptake of 224 cm3 (STP) g−1 and the second-highest volumetric uptake of 196 cm3 (STP) cm−3 at 295 K and 1 atm. Increasing the storage temperature to 308 K has only a small effect on its acetylene storage capacity (∼200 cm3 (STP) g−1). Furthermore, FJI-H8 exhibits an excellent repeatability with only 3.8% loss of its acetylene storage capacity after five cycles of adsorption–desorption tests. Grand canonical Monte Carlo simulation reveals that not only open metal sites but also the suitable pore space and geometry play key roles in its remarkable acetylene uptake.

The efficient storage of high-energy gaseous fuels is problematic due to the risk of explosion. Here, the authors design and employ a metal-organic framework composed of Cu(II) and an octacarboxylate ligand, which is able to store acetylene in high density but at atmospheric pressure.

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