Extended Data Fig. 3: Experimental setup for the graded-pore pyrolysis reactor.

a, The 3D-printed graded-pore reactor was integrated with electrical circuitry to provide Joule heating for pyrolysis. Additionally, the reactor was connected to an inert carrier gas to facilitate the flow of feedstock into the reactor and the discharge of products into the product collection module. The sealed pyrolysis reactor was enclosed inside a quartz tube with Swagelok fittings. After loading polyethylene into the 3D-printed reactor, an electrified heating program initiates pyrolysis and the products are collected in ethyl acetate or a cold trap for liquid products while gaseous products are collected in a gas bag in the collection module. Once the reaction is completed, both the heating and gas flow are stopped. b, An enlarged view of the pyrolysis reactor shows that it is sealed within the quartz tube and connected to both electrical power supply and inert carrier gas.