| Title: | Active Iron Sites of Disordered Mesoporous Silica Catalyst FeKIL-2 in the Oxidation of Volatile Organic Compounds (VOC) |
| Author(s): | Rangus M; Mazaj M; Drazic G; Popova M; Tusar NN; |
| Address: | "National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia. mojca.rangus@ki.si. National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia. matjaz.mazaj@ki.si. National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia. goran.drazic@ki.si. Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bontchev str., bl. 9, 1113 Sofia, Bulgaria. mpopova@orgchm.bas.bg. National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia. natasa.novak.tusar@ki.si" |
| ISSN/ISBN: | 1996-1944 (Print) 1996-1944 (Electronic) 1996-1944 (Linking) |
| Abstract: | "Iron-functionalized disordered mesoporous silica (FeKIL-2) is a promising, environmentally friendly, cost-effective and highly efficient catalyst for the elimination of volatile organic compounds (VOCs) from polluted air via catalytic oxidation. In this study, we investigated the type of catalytically active iron sites for different iron concentrations in FeKIL-2 catalysts using advanced characterization of the local environment of iron atoms by a combination of X-ray Absorption Spectroscopy Techniques (XANES, EXAFS) and Atomic-Resolution Scanning Transmission Electron Microscopy (AR STEM). We found that the molar ratio Fe/Si 0.01 leads to the formation of oligonuclear iron clusters. STEM imaging and EELS techniques confirmed the existence of these clusters. Their size ranges from one to a few nanometers, and they are unevenly distributed throughout the material. The size of the clusters was also found to be similar, regardless of the nominal concentration of iron (Fe/Si = 0.02 and Fe/Si = 0.05). From the results obtained from sample characterization and model catalytic tests, we established that the enhanced activity of FeKIL-2 with the optimal Fe/Si = 0.01 ratio can be attributed to: (1) the optimal concentration of stable isolated Fe(3+) in the silica support; and (2) accelerated diffusion of the reactants in disordered mesoporous silica (FeKIL-2) when compared to ordered mesoporous silica materials (FeSBA-15, FeMCM-41)" |
| Keywords: | Ar-stem Exafs FeKIL-2 VOC decomposition Xanes catalytic oxidation disordered mesoporous silica interparticle mesoporosity isolated iron oligonuclear iron clusters; |
| Notes: | "PubMed-not-MEDLINERangus, Mojca Mazaj, Matjaz Drazic, Goran Popova, Margarita Tusar, Natasa Novak eng Switzerland 2014/05/30 Materials (Basel). 2014 May 30; 7(6):4243-4257. doi: 10.3390/ma7064243" |
