Nanoengoineering of metal organic frameworks for carbon capture


Abstract Global climate change has been subjected to widespread research interest in recent decades while being attributed for its reason to CO2 accumulation of anthropogenic in the atmosphere. Anthropogenic CO2 generation has been accelerated along with growing consumption of fossil fuels since industrial revolution, which is also expected to keep elevating the atmospheric CO2 concentration in the future provided that fossil fuels remain as the major energy resource for human activities. Metal-organic frameworks (MOFs) are an emerging new class of nanoporous crystalline solids built of metal coordination sites linked by organic molecules, which offer well-defined porosity, high surface area, and tunable chemical functionalities, demonstrating applications in catalysis, separation, gas storage, etc. However, due to its physisorption nature of CO2 adsorption process, most of MOFs exhibit unfavorable adsorption capacity at low partial pressure of CO2 along with low N2/CO2 selectivity, which are typical conditions of carbon capture. Application of MOFs to CO2 capture also demands partial or complete drying of gas stream due to its hydrophilicity. Moreover, a strong affinity of open coordination sites in MOFs for H2O is able to provoke structural degradation, during which H2O displaces framework ligands and generates defects in the crystal lattice. Here we present the nanostructure modification of the MOFs to make a functional adsorbent that can afford regenerable CO2 adsorption capacity and materials stability near practical operating conditions of the flue gas or the air capture.