A method comprising contacting a support with a chromium-containing compound and a tin-containing compound to produce a catalyst precursor, and activating the catalyst precursor in a temperature range of from about 400° C. to about 700° C. to produce a polymerization catalyst. A method comprising contacting a support with a chromium-containing compound and a tin-containing compound to produce a catalyst precursor, activating the catalyst precursor in a temperature range of from about 400° C. to about 700° C. to produce a polymerization catalyst, and contacting the polymerization catalyst with ethylene in a reaction zone under suitable reaction conditions to form polyethylene wherein the molecular weight distribution of the polyethylene is broadened.