抄録
Phillips (CrOx/SiO<sub>2</sub>) catalyst is an important industrial ethylene polymerization catalyst, producing more than 7 million of high density polyethylene (HDPE). It is well-known that bimetallic catalyst often has improved activity, and selectivity compared with monometallic one. In this work, bimetallic Phillips-type catalyst was investigated and developed to enhance the Phillips catalyst performance and fabricate a new class of PE. A series of bimetallic Phillips catalysts (CrO<sub>3</sub>/MOx/SiO<sub>2</sub>) were synthesized. Ethylene polymerization was performed at 70 oC and 0.5 MPa of ethylene for 30 min. XPS results revealed that metals having lower electronegativity impart lower electron density on Cr species, plausibly leading to stronger absorption and faster insertion of ethylene. The best improvements were obtained with vanadium-based Phillips catalyst, which improved the catalyst activity by 30% and the branch level by 40%.
