Synthesis, characterization and catalytic properties of Cr-containing silica gel

Chromium-containing silica gel with variable Si/Cr ratios has been synthesized at ambient temperature by a sol-gel method with the addition of different amounts of Cr precursor. A combination of measurements is used to characterize the chromium-containing silica gel. All the analysis indicates following this synthesis route, it is possible to prepare materials without forming extra wall Cr sub(2)O sub(3). And the results show that polychromate is absent in the silica gel materials, while the Cr(VI) of calcined chromium-containing silica gel is present as a monochromate species. Also, it has high activity for the selective oxidation of styrene, which is analyzed periodically by means of gas chromatograph.