1. Mossbauer
57Fe Mossbauer was conducted at 298 K on samples prepared with and without DHP in the gel. In the case of sample prepared with DHP, we found 3 species necessary to adequately fit the acquired spectrum. These include superparamagnetic hematite, Additionally, there appears to only be Fe3+ species present. There is no resonance indicating the presence of six-line magnetic SS such as large-grain Fe2O3. The isomer shifts are all consistent with the presence of only Fe3+ due to absence of resonance indicating the presence of Fe2+ (significantly higher isomer shifts and quadrupole splittings). The very low Fe content sample sprepared without DHP exhibit low relative counts as expected. The presence of any signal may indicate Fe sites due to binding directly to the mesoporous silica. Only the amorphous phase was detected by XRD but any Fe phases are likely below the detection limit.