XAFS Study on Active Iron Sites in MCM41 as a Catalyst for Liquid Phase Oxidation

Hydrophobic Modification of Pd/SiO2@Single‐Site Mesoporous Silicas by Triethoxyfluorosilane: Enhanced Catalytic Activity and Selectivity for One‐Pot Oxidation

“…The isolated tetrahedral Fe is essential for selective oxidation, whereas aggregated Fe species have poor catalytic performance and undesirable H 2 O 2 decomposition 33–35. Thus, Fe K‐edge XAFS measurements were performed to investigate the local structure of the Fe species together with reference compounds, ferrisilicate as isolated tetrahedral Fe and α‐Fe 2 O 3 as aggregated octahedral Fe species35, 36 (Figure 7). The pre‐edge at about 7112 eV in the XANES spectra were attributed to the 1s–3d dipolar forbidden transition.…”

Effect of manganese substitution on the structure and activity of iron titanate catalyst for the selective catalytic reduction of NO with NH3

“…The amorphous MnO x as electrocatalyst by Yang and Xu for oxygen reduction reaction is one of these examples [38]. Shishido et al also concluded that the isolated and tetrahedrally coordinated iron sites with higher degree of structure distortion in the framework of Fe-MCM-41 were responsible for the high activity in oxidation reaction, while small iron oxide clusters with lower degree of structure distortion were not effective [39]. Therefore, we can deduce that the severest distortion of Fe-O and Mn-O coordination structure in our crystallite Fe 0.5 Mn 0.5 TiO x catalyst is also an important reason for its highest SCR activity.…”

The influence of chromium substitution on an iron–titanium catalyst used in the selective catalytic reduction of NO

“…Amorphous CrO x could be one such example. Shishido et al also concluded that isolated and tetrahedrally coordinated Fe sites with high degrees of structural distortion in the framework of Fe-MCM-41 were responsible for the high activity in oxidation reactions, whereas small Fe oxide clusters with lower degrees of structural distortion were not effective [25]. We can therefore deduce that the severe distortions of Fe-O and Cr-O coordination struc- tures in our crystallite Fe 0.5 Cr 0.5 TiO x catalyst are also an important reason for it having the highest SCR activity.…”