CO2-Sorption Properties of Organosilicas with Bridging Amine Functionalities Inside the Framework

The synthesis of amine-bridged organosilicas has been achieved by hydrolysis and polycondensation of bis((triethoxysilyl)propyl) ethylenediamine (BTEPED) and tetraethoxysilane (TEOS) in the presence of an anionic surfactant as a structure-directing agent. The architecture of the mesostructure, surface area, and porosity highly depends on the ratio BTEPED:TEOS. Highly porous solids with high surface areas were obtained when BTEPED:TEOS = 1:x, where x = 7, 5, whereas little porous solids with low surface areas were obtained when BTEPED:TEOS = 1:3 or no TEOS was added. These amine-bridged organosilicas were investigated for their CO2-sorption properties at low pressure. The materials showed high CO2-sorption capacities of up to 2.3 mmol/g at 1 atm. The CO2-sorption capacities increase with the amine loading in the material despite strongly decreasing surface areas.