Multiple Construction of a Nanoporous Pillared-Layered Metal–Organic Framework with High Potential in Adsorption of CO₂, H₂, and N₂ Gases

Abstract

Reduction of atmospheric carbon dioxide, which is one of the main components affecting global warming, and hydrogen storage as a renewable energy source by effective sorbents are considered to be vital challenges. In this work, a nanoporous pillared-layered metal–organic framework of [Zn2(TDC)2(DABCO)]·(DMF)4 (1) (TDC2– = thiophene-2,5-dicarboxylate, DABCO = 1,4-diazabicyclo[2.2.2]­octane, and DMF = N,N-dimethylformamide) as a sorbent was synthesized by several methods, and its structure was determined by single-crystal X-ray analysis. Then, its physicochemical characteristics were investigated by using a set of analyses. The potential of 1 in capturing nitrogen, hydrogen, and carbon dioxide gases at different temperatures showed that the product made by the sonochemical method has a higher capacity for adsorption due to a larger surface area compared to the products of other methods. The maximum capacity of carbon dioxide adsorption is 1.97 mmol·g–1 at 273 K and 1 bar, displaying good MOF performance at low pressures. Also, the hydrogen storage capacity of 1 is higher than several well-known MOFs, such as ZIF-8, MOF-508, and PCN-13, under similar conditions. Moreover, the isosteric heat of carbon dioxide adsorption was calculated at low coverage, revealing the interaction nature between the sorbent surface and gas molecules and the resulting dependence of sorption on the temperature. The better performance of 1 in adsorbing CO2 and H2 molecules compared to some reported MOFs may be related to the surface of the pores decorated with hetero atoms of sulfur.