Constructing bifunctional porous nanosheets for efficient conversion of waste plastics into valuable hydrogen and carbons

Metal oxides as promoting materials can convert waste plastics into hydrogen (H2) fuel by microwave pyrolysis, solving ecological pollution worldwide, but their tendency of agglomeration and poor porosity limit further applications. Herein, we reported a two-dimensional (2D) metal oxide nanosheets with porous network for recycling high-purity hydrogen and carbon nanotubes from waste plastics in microwave-induced reaction. The 2D porous structure significantly improves the growing space of CNTs and enhances the ability of wave absorption, thereby exhibiting a remarkable H2 selectivity of 87.5% and high H2 yield of 60.2 mmol g-1 LDPE, as well as producing high-value CNTs. Moreover, the reaction mechanism for microwave-induced catalytic pyrolysis is proposed, where the Fe2O3 particles on composites facilitated the breakage of C-H bonds, contributing to the generation of H2. The current work provides new insights into the recovery of waste plastics by metal oxides through microwave pyrolysis.

Automated summary

Metal oxides can convert waste plastics into hydrogen fuel by microwave pyrolysis, addressing global ecological pollution. However, agglomeration and poor porosity of metal oxides restrict further applications. In this study, two-dimensional metal oxide nanosheets with a porous network were developed for recycling high-purity hydrogen and carbon nanotubes from waste plastics. The porous structure significantly improved the growing space of carbon nanotubes and enhanced wave absorption, resulting in high H2 selectivity and yield, as well as high-value carbon nanotubes. The reaction mechanism for microwave-induced catalytic pyrolysis was proposed. This research offers new insights into waste plastic recovery using metal oxides through microwave pyrolysis.