Exploration of the role of anions in the synthesis of Cr containing mesoporous materials at room temperature.

Chromium contg. mesoporous silica materials were synthesized via a modified Stoeber synthesis at room temp. The chromium ion loading and the effect of counterion in the synthesis were studied. The mesoporous materials were extensively characterized by powder XRD, N2 physisorption, Atomic Absorption Spectroscopy (AAS), FTIR Spectroscopy (FTIR), Diffuse Reflectance Spectroscopy (DRS UV-visible), hydrogen Temp.-Programmed Redn. (H2-TPR), XPS, and TEM studies. A transition from Ia3̅d cubic phase to p6mm hexagonal or wormhole phases was noted as more amts. of chromium were incorporated into the siliceous materials. Chromium species present in the silica matrix include monochromate, polychromate, and chromium oxide (Cr2O3) clusters. [on SciFinder(R)]