Visible light photocatalytic activities of transition metal oxide/silica aerogels

Silica aerogels containing transition metal (M=Co, Cr, Mn, V, Fe, Cu, and Ni) oxides with high surface areas (>800m2/g) and large pore sizes were synthesized by a modified aerogel method. Those materials with oxides of Co and Cr were found to be the most photoactive for the degradation of gas-phase acetaldehyde with visible light (>420nm).

A combination of various physicochemical techniques such as N2 physisorption, diffuse reflectance UV–Vis (DR-UV–Vis), X-ray diffraction (XRD), FTIR, and Raman were used to characterize these photocatalytic materials, and illustrate differences between them. Comparisons of these M/SiO2 systems with literature reports on M/TiO2–SiO2 and M/TiO2 indicate that well dispersed Cr6+ and Co3+ on aerogel SiO2 make up very active systems both for visible and UV light for photooxidation of gaseous acetaldehyde.