Recycling plastic wastes to fabricate CNTs decoration on Fe-ZrO₂ for the efficient electrocatalytic performance

Recycling and upgrading of plastic wastes to carbon nanotubes (CNTs) for the electrocatalytic application is a meaningful and positive strategy to the environment and energy challenges. Herein, polyethylene (PE) was employed to regulate CNTs decoration on Fe-ZrO₂ catalysts with different morphologies and crystal structures, which was expected to improve the oxygen evolution reaction (OER). Among all Fe-ZrO₂ catalysts, Fe-ZrO₂(III) exhibited the most available Fe₂O₃ sites, and obtained the highest content of CNTs (451.1 mg/g). The particle size of Fe₂O₃ on Fe-ZrO₂(VII) was smaller than that of Fe-ZrO₂(III), which obtained CNTs with a lower diameter (26.0 nm). The OER overpotential of Fe-ZrO₂ with CNTs decoration (Fe-ZrO₂(III)/CNTs and Fe-ZrO₂(VII)/CNTs) was close to each other and approximated to 268 mV at 20 mA/cm², which was 62 mV and 74 mV lower than pristine Fe-ZrO₂(VII) (330 mV) and Fe-ZrO₂(III) (342 mV), and was 20 mV lower than commercial RuO₂ (288 mV). The superior electrocatalytic performance of Fe-ZrO₂ with CNTs decoration was attributed to the presence of CNTs and the accompanied crystal transformation, which improved the electrical conductivity and induced the dual-mechanism for the OER process.