New highly porous materials for safe, low-pressure storage of methane and hydrogen

A new aluminum-based metal-organic framework material achieves both high gravimetric and volumetric uptake and delivery of methane and hydrogen, researchers report. This paves the way for safe and efficient storage of these cleaner fuel alternatives on on-board vehicles. In 2017, U.S. transportation vehicles eclipsed power plants as the largest source of greenhouse gas emissions in the country, and the trend is expected to continue. Methane and hydrogen gas are both potential cleaner alternatives to the gasoline that fuels these vehicles. Use of methane and hydrogen in vehicles, however, requires high-pressure gas compression, which can be difficult to achieve according to the recent U.S. Department of Energy specifications outlining safe on-board storage and delivery in automobiles. In general, the storage pressure for methane and hydrogen in vehicles is limited to 100 bar, significantly reducing the amount of gas that can be stored. However, one way to increase the amount of stored gas without increasing storage pressure is with the use of highly porous adsorbent materials with both high volumetric and gravimetric surfaces. Using molecular simulations to inform their design, Zhijie Chen and colleagues synthesized the ultraporous aluminum-based metal-organic framework, NU-1501-Al. According to Chen et al., in experimental analyses, the material demonstrated impressive gravimetric and volumetric storage performances for both hydrogen and methane. The material surpassed DOE targets for methane and had a deliverable capacity of 14% by weight for hydrogen. The combination of experimentally obtained results and molecular simulations reveals that NU-1501 achieves “outstanding” gravimetric uptake, volumetric uptake, and delivery capacities of methane and hydrogen simultaneously under practical operational conditions, say the authors. This makes this novel class of MOF a promising candidate as a “clean energy carrier.”

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