Weighing in at just one gram, this material can cover a surface area as large as 5000㎡. With just two grams, it can cover more than just about any stadium. This special material is called porous metal-organic frameworks or MOFs. They contain an innumerable number of micro-sized pores, and when fully stretched out, they can cover an unfathomably large area.

Porous MOFs consist of metal ions that are able to connect to organic ligands in several ways to form one, two, or three-dimensional structures. The most noteworthy characteristic of MOFs would be the fact that their properties can be tailored by designing metals and organic molecules as intended. The concept itself is similar to Lego blocks that children stack up to build an airplane or house.

The Park Group, led by Professor Sarah Sunah Park, studies the ‘chemistry of functional inorganic materials’, and is researching how to design various MOFs and discover where they can be applied. One would easily compare the metal and/or organic ligands that make up MOFs to Lego blocks: a choice of blocks may determine the properties of the final creations and the collective assembly of blocks could result in shapes or properties previously deemed unimaginable. This is precisely what researchers at the lab are doing – leveraging a range of metals and organic ligands to design and synthesize MOFs that exhibit novel properties.

As the components of MOFs dictate surface area limits, this is boosting research initiatives on how to fabricate MOFs that feature a more efficient and larger storage capacity. Prime examples include the storage of hydrogen and the safe storage and transport of toxic substances.

The Park Group is taking its research one step further and designing electrically-conductive materials able to transmit electrons or ions. This is indeed a daunting challenge given that MOFs are extremely porous, making it difficult to move the electrons and ions. In particular, the combination of metal ions and organic ligands results in an energy discrepancy which hinders the mobility of electrons.

The Park Group focuses on designing MOF structures with high electrical conductivity that can support large surface areas. Research is currently underway to use these structures for novel battery cathode materials or electrochemical catalysts.

The ultimate goal of the Park Group is to synthetize materials that present a completely novel structure through MOF technology. Essentially, their aim is to design new materials through predicting their properties and studying the correlation between their properties and structures, so that they can be applied to energy storage and electrochemical catalysis.

Professor Park noted “It is extremely intriguing that we can accurately ascertain the structure of a given material through the X-ray structural analysis of MOFs”, and added “As new materials are designed and their properties discovered through direct experimentation, the research process itself becomes even more interesting”.