A series of heterogeneous metallocene catalysts were prepared by encapsulating Cp2ZrCl2 within silica-polystyrene hybrid support. Immobilization was performed through a non-hydrolytic sol–, gel process in which polystyrene (PS) dissolved in toluene and metallocene (1% by wt) were combined. The effect of PS (0 to 5% by wt) and silicon tetrachloride (0. 5 to 1. 6 [TEOS]/[SiCl4]) was evaluated in terms of catalyst activity in ethylene polymerization with methylaluminoxane as the cocatalyst. According to FTIR measurements, an increase in PS content promoted a decrease in (SiO)6 content, which indicated the formation of more compact structures. Furthermore, homogeneous distributions of polymer and silica phases were observed both in bulk and on the support surface. The results showed very small surface areas (< , 20 m2 g−, 1), probably because PS would fill the silica pores. The catalytic activity for ethylene polymerization was shown to decrease with increasing polystyrene content within the catalyst support of low surface area. A positive correlation was found between the (SiO)6 content and catalyst activity. The increase in the PS content was followed by an increase in the degree of polyethylene crystallization, which ranged from 77 to 84%.