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

Abstract

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, MOF-808(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.

Zirconium-Based Metal–Organic Frameworks as Acriflavine Cargos in the Battle against Coronaviruses─A Theoretical and Experimental Approach

“…The modulated synthesis was under intense investigation for various Zr-MOF structures including UiO-66, 30 − 32 UiO-67, 33 and MOF-808. 34 In work by Shearer et al, 31 structural defects in UiO-66 were deeply investigated, and more recently, the nature of the defects in UiO-66 structure was examined by HRTEM microscopy by Liu et al. 35 …”

Coordinatively Unsaturated Hf-MOF-808 Prepared via Hydrothermal Synthesis as a Bifunctional Catalyst for the Tandem N-Alkylation of Amines with Benzyl Alcohol

“…Recently, the green preparation of different MOF-type materials, particularly UiO-66 and MOF-808, has been described via modulated hydrothermal synthesis (MHT). ,, In these cases, water is used as the solvent during their crystallization, avoiding the use of N , N -dimethylformamide (DMF), a common and highly toxic solvent in the traditional solvothermal syntheses. Interestingly, it has been shown that the relative amount of defective −OH groups within the metallic nodes in MOFs can be substantially increased when the MOF preparation is carried out via MHT synthesis compared to the more classical solvothermal approach, a fact that unavoidably influences the adsorption and catalytic properties .…”

Tailoring Lewis/Brønsted acid properties of MOF nodes via hydrothermal and solvothermal synthesis: simple approach with exceptional catalytic implications

“…23 For this reason, an alternative modulated hydrothermal approach has been recently applied to successfully synthesize the 12-connected UiO-66 material and the 6-connected MOF-808, both with Zrand Hf-composition. [24][25][26][27] It is worth noting that traditional solvothermal processes require the use of large amounts of organic solvents, preferentially N,N-dimethylformamide (DMF), which is toxic, ammable and carcinogenic. Thus, these hydrothermally-mediated synthesis methods can be considered as substantial advances in MOF-type preparation, allowing their synthesis following an environmental-friendly pathway that can undoubtedly facilitate their scale-up preparation.…”