Collaborative Pt-Ni Sites Enable CO-Tolerant Hydrocracking for Upcycling Polyolefin Waste

Hydrocracking is a significant chemical route for recycling waste plastic. Utilizing inexpensive crude hydrogen to drive this reaction offers substantial economic benefits. However, CO, the primary impurity in crude hydrogen, readily poisons the metal sites, leading to catalyst deactivation. Herein, we report a CO-tolerant catalytic system constructed by blending silicalite-1 zeolite (S1)-encapsulated Pt-Ni binary metals with Ce-modified HY zeolite, which possesses exceptional capability for converting polyethylene into C3-C5 products. For comparison, the monometallic counterparts based on either Pt or Ni manifest pronounced deactivation under the same conditions. Sequential investigations reveal that this catalytic system follows a "two-way compensation" mechanism. In the presence of CO, Pt experiences a loss of hydrogenation activity while retaining its dehydrogenation capability. Conversely, Ni loses its dehydrogenation ability but maintains its hydrogenation capacity. The synergistic combination of Ni and Pt effectively compensates for each other's functional shortcomings, ensuring the seamless progression of the hydrogenation reaction.