Solid-State Investigation, Storage, and Separation of Pyrophoric PH3 and P2H4 with α-Mg Formate

Abstract

Phosphane, PH3—a highly pyrophoric and toxic gas—is frequently contaminated with H2 and P2H4, which makes its handling even more dangerous. The inexpensive metal–organic framework (MOF) magnesium formate, α-[Mg(O2CH)2], can adsorb up to 10 wt % of PH3. The PH3-loaded MOF, PH3@α-[Mg(O2CH)2], is a non-pyrophoric, recoverable material that even allows brief handling in air, thereby minimizing the hazards associated with the handling and transport of phosphane. α-[Mg(O2CH)2] further plays a critical role in purifying PH3 from H2 and P2H4: at 25 °C, H2 passes through the MOF channels without adsorption, whereas PH3 adsorbs readily and only slowly desorbs under a flow of inert gas (complete desorption time≈6 h). Diphosphane, P2H4, is strongly adsorbed and trapped within the MOF for at least 4 months. P2H4@α-[Mg(O2CH)2] itself is not pyrophoric and is air- and light-stable at room temperature.