A process of producing a bimodal polyolefin composition is described, which includes in one embodiment contacting monomers with a supported bimetallic catalyst composition for a time sufficient to form a bimodal polyolefin composition that includes a high molecular weight polyolefin component and a low molecular weight polyolefin component; wherein the supported bimetallic catalyst includes a first catalyst component that is preferably non-metallocene, and a second catalyst component that includes a metallocene catalyst compound having at least one fluoride or fluorine containing leaving group, wherein the bimetallic catalyst is supported by an enhanced silica, dehydrated at a temperature of 800 C. or more in one embodiment.