CO2-mediated catalytic upcycling of plastic waste for H2-rich syngas and carbon nanomaterials

Xuesong Zhang; Yuan Jiang; Ge Kong; Quan Liu; Guanyu Zhang; Kejie Wang; Tianqi Cao; Qing Cheng; Ziyi Zhang; Guanya Ji; Lujia Han

doi:10.1016/j.jhazmat.2023.132500

CO₂-mediated catalytic upcycling of plastic waste for H₂-rich syngas and carbon nanomaterials

J Hazard Mater. 2023 Oct 15:460:132500. doi: 10.1016/j.jhazmat.2023.132500. Epub 2023 Sep 7.

Authors

Xuesong Zhang¹, Yuan Jiang², Ge Kong², Quan Liu², Guanyu Zhang², Kejie Wang², Tianqi Cao², Qing Cheng², Ziyi Zhang², Guanya Ji³, Lujia Han⁴

Affiliations

¹ Engineering Laboratory for AgroBiomass Recycling & Valorizing, College of Engineering, China Agricultural University, Beijing 100083, China. Electronic address: xszhang@cau.edu.cn.
² Engineering Laboratory for AgroBiomass Recycling & Valorizing, College of Engineering, China Agricultural University, Beijing 100083, China.
³ School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
⁴ Engineering Laboratory for AgroBiomass Recycling & Valorizing, College of Engineering, China Agricultural University, Beijing 100083, China. Electronic address: hanlj@cau.edu.cn.

PMID: 37708645
DOI: 10.1016/j.jhazmat.2023.132500

Abstract

To establish a reliable disposal platform of plastic waste, this work developed a novel dual-stage CO₂-medaited decomposition-catalysis route by applying multi-functional zeolite-supported bimetallic catalysts. Catalytic upcycling of plastic was first performed in Ar as a reference environment. Bimetallic Fe-Co/ZSM5 catalyst achieved the highest gas yield (53.98 mmol/g), with a H₂ proportion of 62.17 vol%. It was evidenced that the Fe-Co alloy had an apparent positive synergistic effect on catalytic cracking and reforming of intermediate volatiles into H₂-rich fuel gas and pure carbon nanotubes (CNTs). Regarding CO₂-mediated decomposition-catalysis of plastic, there was an apparent synergistic effect between metallic Ni and Fe on gas production so that bimetallic Ni-Fe catalyst gained the maximum cumulative gas yield of 82.33 mmol/g, with a syngas purity of ∼74%. Ni-Fe/ZSM5 also achieved the maximum hydrogen efficiency (87.38%) and CO₂-to-CO conversion efficiency (98.62%), implying hydrogen content in plastic and oxygen content in CO₂ were essentially converted into gases. Additionally, bimetallic Ni-Fe catalyst revealed the highest carbon production (33.74 wt%), witnessing a synergistic enhancement of 43.45%; specially, approximately 257 mg/g CNTs were anchored on Ni-Fe/ZSM5, with a CNTs purity of over 76%. Overall, this study offers a superb solution in plastic waste valorization and greenhouse gas emission management.

Keywords: Bimetallic synergistic catalytic effect; CNTs; CO(2)-mediated decomposition-catalysis; H(2); Syngas.