Bifunctional magnetic Co3O4-B/C catalysts for the thermochemical conversion of non-reciclable plastic waste

Abstract

The work presents a catalytic study focused on the valorization of the gas fraction generated during the pyrolysis of non-recyclable plastic waste. It encompasses both the development of catalytic materials and the optimization of a two-step process aimed at improving the gas composition toward a hydrogen-rich stream. The catalysts were synthesized through a simple and scalable solvent-less approach. The most promising material, a ternary Co₂O₃/B/Carbon system, not only exhibited remarkable catalytic activity but also displayed magnetic properties that facilitate its separation during the in situ pyrolysis stage, achieving 103.3 mmol of H2 produced at 1 h (5.2 mmol of H2 g−1 of the plastic), with H₂/CO > 2.0 and H₂/(CO + CO₂) of 1.6, representing a 43 % increase in the amount of H₂ produced compared to single-stage operation. The study identifies and discusses the roles of the Co-related metallic components supported on carbon, as well as the contribution of the minor boron species. Overall, this work provides clear evidence of the potential of a two-step catalytic configuration for the valorization of plastic residues that currently accumulate in landfills.