Study On Hydrogen Storage Properties Of Novel Metal-organic Frameworks(MOFs)Materials

Hydrogen is the ideal energy for new energy powered vehicle,but the efficient hydrogen storage technology is lacked.Because of their large specific surface area and adjustable pore structure,Metal Organic-Frameworks have been extensively studied in the field of solid-state gas storage.However,there is no report on the application of MOFs hydrogen storage on carriers such as vehicle and ship.In this report,hydrogen storage behavior in two systems of Metal Organic Frameworks(MOFs),MOF-X(X=801,806,808,841)and highly connected MOFs with edge-transitive,have been studied by means of the method of Grand Canonical Monte Carlo(GCMC).The model of Non Local Density Functional Theory(NLDFT)was used to analyze their pore size distributions.The results reveal that all MOFs behave good hydrogen storage properties in the condition of temperature at 77 K,which can meet the requirements of the U.S.Department of Energy(DOE).It is worth mentioning that Y-shp-MOF-1 behaves best hydrogen storage properties due to a number of advantages over others such as the most narrow pore,largest specific surface area and pore volume,whose hydrogen storage volume densities and gravimetric densities are 0.079 kg/L and 11.1 wt%,respectively,in 1000 k Pa pressure condition.At the same time,two platforms on adsorption isotherm due to two different pore structure are present on one material and their pore size difference is evident.Meanwhile,for predict the potential application that MOFs as the hydrogen storage materials for on-board vehicle,studied the adsorption properties of hydrogen in high-connected MOFs with edge-transitive nets in ordinary temperature at 298 K.Study result showed that all MOFs hydrogen storage capacities can meet 2020 target of DOE.Hydrogen storage volume density of Y-shp-MOF-1 is 1.75 times of current commercial Type IV 700 bar compressed tank at the same conditions,and which can meet the equal efficiency only in 140 bar hydrogen process,so,it is able to as the new material applied on on-board hydrogen storage system.In addition,Methane adsorption and selective Methane/Hydrogen adsorption properties in highly connected MOFs with edge-transitive net also tested,results were shown that which can not only storage most of hydrogen and Methane adsorption capacity is also excellent.Unfortunately,the property of selective Methane/Hydrogen adsorption is ordinary,whose selective adsorption capacity need further study.