Towards a novel approach to capture CO2 in hierarchically organized chemically functionalized materials

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The capture of combustion generated CO2 will remain a critical tasks in a sustainable long term scenario for carbon based energy use. To address this issue, the development of materials with fast and efficient CO2 uptake at high space velocities, which are stable in presence of water vapor and easy to regenerate, is necessary. To address this challenge, the knowledge-based development of a novel family of hierarchically structured amine functionalized silica based particulate materials is proposed. Within the project we have already identified the density and accessibility of the amine groups to be crucial parameters for the design of a successful material. Functionalization with primary, secondary and bibasic amine groups was investigated and the local interaction between CO2 and the basic functionality was studied. Intermolecular interactions dominated as the carbon chain in the bibasic molecules appeared to be not flexible enough for an intramolecular binding of CO2, which would be advantageous for an efficient capturing of CO2. Thus we propose to develop materials which will enable the interaction of CO2 with two amine groups present in the same amine molecule anchored to the SiO2 spheres. As the CSS processes will be carried out without drying the flue gas stream we will address the surface chemistry, the macroscopic uptake capacities and the uptake rates in the presence of water vapor. The kinetics of the adsorption and regeneration processes will be investigated and the diameters as well as the hydrophobicity of the pore systems will be optimized. As final point in the project we will evaluate concepts for a reactive regeneration of the CO2 sorbents, which shall allow to directly convert the CO2 bound on the materials with H2 to energy carries such as methanol. This will allow to overcome the current restrictions in CO2 storage and enables delocalized utilization of this technology at remote CO2 emission sources.