Catalytic Hydrocracking of Synthetic Polymers into Grid-Compatible Gas Streams

Abstract

The utilization of methane as one of the cleanest energy sources has received significant public awareness and methane productions with less environmental impact than fracking are receiving considerable attention. Catalytic hydrocracking of plastic materials has been considered as a clean alternative scenario. However, a catalyst that converts heterogeneous plastic feeds into a single product under industrially relevant conditions is lacking. Here we describe a ruthenium-modified zeolite which catalytically transforms polyethylene, polypropylene and polystyrene into grid compatible methane (>97% purity), at 300 oC using near-stoichiometric amounts of hydrogen. Mechanistic studies reveal a chain-end initiation process with limited isomerization of plastic substrates. A ruthenium-site dominant mechanism is proposed based on these studies and DFT computations. We foresee such a plastic-to-methane process advances upon the intelligent utilization of plastic waste via energy recovery, also accommodates emerging sustainable hydrogen productions into existing natural gas networks, integrating waste management, fuel production and energy storage.