PREPARATION AND CHARACTERIZATION OF POROUS SILICA SPHERES CONTAINING A COPPER(OXIDE) CATALYST

Porous catalyst (sorbent) spheres have been prepared by incorporation of a finely divided catalyst precursor into a silica gel matrix. The newly developed preparation procedure facilitates independent control over the dispersion of the active material and the porous structure of the support. As an example the preparation of porous copper-on-silica spheres is described. Scanning electron microscopy shows that the incorporated catalyst is homogeneously distributed throughout the silica gel matrix. The texture of the porous spheres has been investigated by means of water thermoporometry and nitrogen adsorption. The pore structure of the spheres can be modified by application of a hydrothermal treatment. Under prolonged hydrothermal treatment the mean pore size gradually increases from 3 to 30 nm, whereas the specific surface area simultaneously decreases from 550 to 100 m2/g. The effect of the texture of the silica matrix on the accessibility of the incorporated copper catalyst has been inv estigated by means of temperature-programmed reduction and by catalytic oxidation of carbon monoxide to carbon dioxide. The results indicate that the accessibility of the incorporated catalyst is improved by the presence of wider pores in the silica matrix. © 1990.