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 m(2) 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, MOF808(Hf) shows a volumetric methane deliverable capacity of 110 v(STP) 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.