THE SOL-GEL PREPARATION OF POROUS CATALYST SPHERES

A silica sol-gel process was used to prepare porous catalyst spheres. A separately prepared suspension of a silica-supported copper catalyst was added to a silica sol. Droplets of the mixture thus obtained, were sprayed into hot paraffin to facilitate sol-gel conversion. By this procedure porous copper-on-silica hydrogel spheres were prepared. A hydrothermal treatment was used to establish the final texture. The copper-on-silica suspension is homogeneously distributed through the silica gel matrix. The texture of the spheres can be adapted by varying the hydrothermal conditions. Temperature-programmed reduction shows the reduction behavior to depend upon both the pore-size distribution and copper particle size. It appears that upon hydrothermal treatment the copper surface is (partly) covered by silica, which slows down the reduction.