Preparation of mesoporous ferrisilicate with high content of framework iron by pH-modification method and its catalytic performance

The mesoporous ferrisilicates (MFS) with high iron content were synthesized by pH-modification method, and the iron content could be up to 10.5 wt.% (Si/Fe = 8). The pH was kept less than 2 at pre-hydrothermal synthesis step and was adjusted to 11 during hydrothermal step. The samples were characterized by XRD, HRTEM, N2-sorption, XRF, FTIR, DRUV–vis, Fe K-edge EXAFS, EPR, and DSC. The results suggested that the MFS materials were ordered 2D hexagonal mesophase of MCM-41, and the iron atoms were tetrahedral coordinated in the silica framework. This material could efficiently catalyze the hydroxylation of phenol in water medium using H2O2 as an oxidant, and the phenol conversion could be up to 52% under the optimal experimental conditions.

The mesoporous ferrisilicates (MFS) with high iron content were synthesized by internal pH-modification method, and the Fe K-edge XAFS results indicate Fe3+ ions incorporate into the silicate framework with a tetrahedral coordination structure.Figure optionsDownload high-quality image (52 K)Download as PowerPoint slideHighlights
► Mesoporous ferrisilicates with high content of iron were prepared via pH-modification method.
► The optimum limit of iron in the silicate framework could be up to 10.5 wt.% (Si/Fe = 8).
► The color of high iron content mesoporous ferrisilicate is white.