Synthesis and characterization of SBA-15 silica containing cyclam inside pores for capturing iron chloride: Analysis of interactions between ferrous chloride and cyclam in a system with strongly dispersed functional groups on the SiO2 surface

Abstract

The use of the spatial structure of mesoporous silica combined with organic molecules opens up a wide range of possibilities in the field of separation of single atoms and the precise creation of their environment. Materials obtained in this way can find applications as single-atom catalysts (SAC) and in environmental applications in ion and molecule trapping processes. An example of such a material is silica of the SBA-15 type functionalized with cyclam (1,4,8,11-tetraazacyclotetradecane) anchored inside the pores with propyl chains. In this work, we present such a material containing 5% functional groups, additionally activated with iron(II) chloride, which was chelated by cyclam anchored inside the pores of silica. The presented nanocomposite has been thoroughly tested for its assumed molecular structure and stability. We compared it to a material containing only cyclam. The obtained results showed the high efficiency of the silica matrix with cyclam in the separation of single FeCl2 molecules and the correct molecular structure of the obtained material. The nanocomposite containing chelated molecules with iron showed good stability, while the structure of the material with cyclam alone collapsed with time.