Synthesis and characterization of a novel composites derived from SBA-15 mesoporous silica and iron pentacarbonyl

J Colloid Interface Sci. 2022 Feb 15;608(Pt 3):2421-2429. doi: 10.1016/j.jcis.2021.10.164. Epub 2021 Oct 30.

Abstract

Hypothesis: Fe(CO)5 was deposited on SBA-15 from gaseous phase and the adsorbed iron precursor was oxidized and hydrolyzed. We hypothesize that a novel method produces composites of unique and useful properties. The absence of sulfur and halides in the composites is of special importance with respect of their potential application as catalysts and catalyst supports.

Experiments: We obtained composites containing 1.3-157.5% of iron oxide with respect to silica (counted as 100%). The new materials were characterized by specific surface area, XRD (X-ray diffraction), Mossbauer spectroscopy, electron microscopy coupled with EDS (energy dispersive X-Ray spectroscopy), and microelectrophoresis.

Findings: In the composites low in iron (<57% of iron oxide) the Mossbauer spectra showed only doublets, which were interpreted as tiny nanoparticles of Fe(III) oxide in the pores of SBA-15. In the composites high in iron (>65%) the Mossbauer spectra showed doublets and sextets. The later were interpreted as larger nanocrystals of hematite, and the presence of such nanocrystals was confirmed by XRD. EDS confirmed that in the composites low in iron, iron oxide was evenly distributed in the entire volume of pores of SBA-15.

Keywords: BET; Chemical vapor deposition; Composites; Mesoporous silica; Mössbauer spectroscopy; SBA-15; XRD; ζ potential.

MeSH terms

  • Catalysis
  • Ferric Compounds*
  • Iron Compounds
  • Silicon Dioxide*

Substances

  • Ferric Compounds
  • Iron Compounds
  • SBA-15
  • iron pentacarbonyl
  • Silicon Dioxide