Modulated Hydrothermal Synthesis of Highly Stable MOF-808(Hf) for Methane Storage

The scaling-up issue, mechanical instability, and possible packing capacity loss during pelletization remain as the major obstacles for the application of metal–organic frameworks (MOFs) in practical methane storage. Herein, we present the modulated hydrothermal (MHT) synthesis of high-quality MOF-808(Hf) in a green and sustainable way at a high production rate of 1.8 g h–1 and space time yield of 86.8 kg m–3 day–1. The MHT approach endows MOF-808(Hf) with a Brunauer–Emmett–Teller surface area of 1210 m2 g–1, which is comparable to those synthesized from the solvothermal approach. MOF-808(Hf) demonstrates a higher elastic modulus (37.5 ± 3.4 GPa) than that of MOF-808(Zr) (26.9 ± 5.2 GPa). In addition, MOF-808(Hf) shows a volumetric methane deliverable capacity of 110 vSTP v–1, which is among the highest-performing Zr/Hf-based MOFs for methane storage. It is worth noting that MOF-808(Hf) exhibits a higher pelletizing resistance than that of MOF-808(Zr) because of its higher structural integrity (mechanical strength), which makes this material promising for high-pressure natural gas storage.