Superior Storage and Controlled Release of Oxygen by Solid Clathrates under Ambient Conditions.

Abstract

A concentrated O₂ supply is essential in medical systems, submarines, aircraft, and in space technology. However, it remains challenging to discover solid materials for O₂ storage, particularly those that offer structural stability and O₂-capturing characteristics under ambient conditions. Here, we report solid hydroquinone clathrate crystals encapsulating O₂ molecules, potentially allowing long-term storage and recycling at room temperature and ambient pressure. Through comprehensive structural analyses, molecular dynamics simulations and density functional theory calculations, we identify an energetically favorable and cooperative ordering of host and guest molecules to build hydrogen-bonded organic clathrate frameworks from amorphous morphology. Hydroquinone clathrate has a capacity of 2.45 mmol g^-1 for O₂ storage at 1 bar and 298 K, far exceeding the capabilities of earlier porous nanostructured materials. In both as-synthesized powder and pellet forms, this hydroquinone clathrate fully retains its O₂ storage performance for a long time over 100 days. The controlled release of O₂ from hydroquinone clathrate pellets can be tuned simply by temperature variations with excellent cycling stability, showing no loss of the O₂ uptake after repeated cycles.