Fe, Co and Cu-incorporated TUD-1: Synthesis, characterization and catalytic performance in N 2O decomposition and cyclohexane oxidation

Abstract

Fe, Co and Cu-TUD-1 were prepared with different metal loadings (Si/M ratio = 100, 50, 20 and 10). As a function of increasing metal loading either isolated metal atoms, nano-particles of M-oxide and/or bulk M-oxide crystals in the silicate matrix were obtained, respectively. The materials were fully characterized by means of XRD, UV–vis, elemental analysis, N 2 sorption measurements and HR-TEM. The catalytic performance of the prepared materials was tested in gas phase N 2O decomposition and in liquid phase oxidation of cyclohexane. Results of N 2O decomposition showed that a low M-loading is beneficial for the catalysis and leads to a high TOF, Co-TUD-1 being the most active catalyst. This suggests that the nano-particles observed in many catalysts are not dominating the N 2O decomposition rate, and that active phase entities ranging from isolated to polynuclear sites are the most active. The performance of the TUD-1 catalysts is significantly lower than reported for the microporous Fe, Co and Cu analogues. In the oxidation of cyclohexane with TBHP, Cu-TUD-1 showed the highest activity but also significant leaching. Co-TUD-1 did not show any leaching and is thus the best applicable catalyst in cyclohexane oxidation.