Suppressing Hydrogen Transfer and Aromatization Reactions Enables Efficient Photothermal Recycling of Polyethylene into Platform Olefins

Abstract

ABSTRACT The recycling of polyethylene (PE) into highly selective platform olefins holds great promise as a potential closed‐loop recycling route that minimizes dependence on the petrochemical industries, whereas the selectivity of olefins is mainly limited by two side reactions: hydrogen transfer and aromatization. Herein, we present a photothermal recycling pathway that effectively converts various types of PE into highly selective olefins using ZnCrO x /HZSM‐5 composite catalyst, with efficaciously suppressing both side reactions. The inclusion of ZnCrO x modifies catalyst acidity to inhibit the hydrogen transfer reaction, while jointly establishing an intra‐catalyst spatial temperature gradient through distinct photothermal responses between ZnCrO x and HZSM‐5 whereby the endothermic aromatization can be suppressed. This strategy achieves an impressive selectivity of 75.4% for C 2 –C 5 hydrocarbons, with 84.7% of them being C 2 –C 5 olefins, in the photothermal recycling of low‐density PE (LDPE) under atmospheric pressure using Xe lamp irradiation. Further, the demonstrated universality across various PE feedstocks (e.g., high‐density PE and commercial LDPE bags) and concentrated sunlight operation highlights a solar‐powered plastic‐to‐olefin platform with industrial viability.