Catalytic properties in N2O decomposition of mixed cobalt–iron spinels

The effect of introduction of iron in the Co3 − xFexO4 on catalytic activity in N2O decomposition was investigated. The spinel catalysts were characterized by XRD, SEM, RS, BET methods, work function measurements and Mössbauer spectroscopy. Introduction of iron in the Co3 − xFexO4 spinel catalysts at the level of x < 1 leads to preferential substitution of Fe3+ in tetrahedral sites, whereas for x > 1 also octahedral ones are substituted. A strong correlation between deN2O activity (T50%) and work function was observed showing that electronic factor controls the catalytic reactivity of Co–Fe spinels. The results revealed that the active centers for N2O decomposition are cobalt ions and thus even a low level of their substitution by iron leads to substantial decrease of the deN2O activity of the cobalt spinel.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The series of Co3 − xFexO4 (0 ≤ x ≤ 3) samples were investigated. ► Catalytic activity of cobalt–iron spinels was tested towards decomposition of N2O. ► Direct correlation between the N2O conversion and electron work function was found. ► Fe3+ ions in tetra- and octahedral sites deactivates of the cobalt active centers.