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

在基于碳的能源使用的可持续长期情景中，捕获燃烧产生的二氧化碳仍将是一项关键任务。为了解决这个问题，开发在高空间速度下快速有效地吸收二氧化碳的材料是必要的，这种材料在水蒸气存在下是稳定的，并且容易再生。为了应对这一挑战，提出了一种基于知识的新型层次化胺功能化二氧化硅颗粒材料家族的开发。在该项目中，我们已经确定胺基的密度和可获得性是设计成功的材料的关键参数。考察了伯胺、仲胺和双胺的官能化反应，并研究了CO2与碱性官能团的局部相互作用。分子间相互作用占主导地位，因为二元分子中的碳链似乎不够灵活，不足以与二氧化碳在分子内结合，这将有利于有效地捕获二氧化碳。因此，我们建议开发能够使二氧化碳与固定在二氧化硅球体上的同一胺分子中的两个胺基团相互作用的材料。由于在不干燥烟道气流的情况下，将进行CS过程，我们将讨论表面化学、宏观吸收能力和在存在水蒸气的情况下的吸收速率。将对吸附和再生过程的动力学进行研究，并对孔系统的直径和疏水性进行优化。作为项目的最后一点，我们将评估二氧化碳吸附剂反应再生的概念，这将允许将与氢结合的材料上的二氧化碳直接转化为能量载体，如甲醇。这将允许克服目前在二氧化碳储存方面的限制，并使这项技术在远程二氧化碳排放源的非本地化使用成为可能。

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.