A porous metal–organic framework with an elongated anthracene derivative exhibiting a high working capacity for the storage of methane

Abstract

We have developed a new porous metal–organic framework (MOF) (UTSA-80) with an elongated anthracene derivative as a linker. The activated UTSA-80a has a pore volume of 1.03 cm³ g⁻¹ and a gravimetric Brunauer–Emmett–Teller surface area of ca. 2280 m² g⁻¹, higher than those of PCN-14. The volumetric methane storage capacity of UTSA-80a at 35 bar and 298 K is 192 cm³ (STP) cm⁻³, which makes it one of the few porous MOFs with a storage capacity >190 cm³ (STP) cm⁻³ at 35 bar. The volumetric uptake of methane by UTSA-80a reaches 233 cm³ (STP) cm⁻³ at room temperature and 65 bar; this is 88.6% of the new volumetric target of the US Department of Energy if the packing density loss is ignored. This capacity is comparable with that of PCN-14. However, as a result of the lower methane uptake of UTSA-80a at 5 bar, it has a much higher methane storage working capacity (deliverable amount of methane between 65 and 5 bar) of 174 cm³ (STP) cm⁻³ compared with PCN-14 [157–160 cm³ (STP) cm⁻³]. This value is slightly lower than the 190 cm³ (STP) cm⁻³ achieved by HKUST-1, suggesting that it is a promising material for methane storage in transport applications. Such an exceptionally high working capacity can probably be attributed to the elongated anthracene derivative used as a linker within UTSA-80a, which adjusts the pore sizes/cages and interactions with the methane molecules to optimize the methane working capacity.