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The need for alternative fuels is greater now than ever before. With considerable sources available and low pollution factor, methane is a natural choice as petroleum replacement in cars and other mobile applications. However, efficient storage methods are still lacking to implement the application of methane in the automotive industry. Advanced porous materials, metal-organic frameworks and porous organic polymers, have received considerable attention in sorptive storage applications owing to their exceptionally high surface areas and chemically-tunable structures. In this critical review we provide an overview of the current status of the application of these two types of advanced porous materials in the storage of methane. Examples of materials exhibiting high methane storage capacities are analyzed and methods for increasing the applicability of these advanced porous materials in methane storage technologies described.

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Metal–organic frameworks (MOFs) are very important in the development of new technologies and study of gas storage and separation. MOFs are based on the complexation of metal clusters with organic ligands. Occasionally, the same building components combine in multiple different ways to produce different structures. These different structures are what we would call “framework isomers.” This type of isomerism is unique to the field of MOFs. In this Perspective, we classify the different types of framework isomers and provide examples of each type. Additionally, we provide an analysis of the structure/property relationship. In addition, possible methods for future control over the synthesis of a particular framework isomer and characterization techniques have also been discussed.

An isostructural series of NbO-type porous metal-organic frameworks (MOFs) with different dialkoxy-substituents of formula Cu 2 (TPTC-OR) (TPTC-OR = 2',5'-di{alkyl}oxy-[1,1':4',1''-terphenyl]-3,3'',5,5''-tetracarboxylate, R = Me, Et, n Pr, n Hex) has been synthesized and characterized. The moisture stability of the materials has been evaluated and a new superhydrophobic porous MOF has been identified. The relationship between pendant side chain length and thermal stability has been analyzed by in situ synchrotron powder X-ray diffraction, showing decreased thermal stability as the side chain length is increased, contradictory to thermogravimetric decomposition studies. Additionally, the four materials exhibit moderate Brunauer-Emmett-Teller (BET) and Langmuir surface areas (1127 -1396 m 2 g -1 and 1414 -1658 m 2 g -1 ), and H 2 capacity up to 1.9 wt% at 77 K and 1 bar.