A catalyst system is provided which comprises a solid support material having, on its surface, one or more catalytic transition metal complex wherein the solid support material comprises SiO2@AMO-LDH microspheres having the formula I: (i) wherein, Mz+ and M′y+ are two different charged metal cations; z=1 or 2; y=3 or 4; 0 0.01 and 0 q>0; Xn− is an anion with n>0, preferably 1−5a=z(1−x)+xy−2; and the AMO-solvent is an 100% aqueous miscible organic solvent. Preferably, M′ in the formula I is Al. Preferably, M in the formula I is Li, Mg or Ca. The catalyst system has use in the polymerization and/or copolymerization of at least one olefin to produce a homopolymer and/or copolymer.