Fluorine-assisted asphalts waste carbonization to Ni-F-C electrocatalyst by mechanochemistry for efficient oxygen evolution

• Published in: Fuel (Guildford) 2024-11, Vol.375, p.132612, Article 132612
• Main Authors: Zhao, Jiahua, Zhou, Xuanyu, Niu, Qiang, Zhang, Junjun, Zhang, Pengfei
• Format: Article
• Language: English
• Subjects: Asphalt upgrade; Fluorine modification; Oxygen evolution reaction; Resource recycling; Surface reconstruction
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.132612

[Display omitted] •Ni-F-C derived from asphalts waste was synthesized by mechanochemistry for resource recycling.•The evolution of active species, the roles of porosity, carbon substrate and dynamic fluorine migration were verified.•Ni-F-C needs 269 mV to drive 10 mA cm−2 for OER and showed long-term stability (∼150 h). Low-cost Ni-F-C electrocatalysts were gram-scale synthesized through mechanochemical synthesis accompanied by asphalt and e-waste polytetrafluoroethylene (PTFE) upgrading. The high-value utilization of bulk industrial solid waste and the design of high-performance oxygen evolution electrocatalyst hold immense importance for sustainable environment and energy economy. The overpotential at 10 mA cm−2 (1 M KOH) for the optimized Ni-F-C catalyst was low as 269 mV. First, PTFE as a pore-forming agent generated plenty of pores inside the Ni-F-C catalyst (promoting mass transfer and surface wettability). Second, the structural self-reconstruction caused by fluorine migration made the electrode surface undergo in-situ transformation from Ni species to Ni-OOH/OH phase during OER. Additionally, DFT calculations demonstrated that the F atoms could trigger charge redistribution, effectively activate adjacent Ni atoms and reduce the energy barrier of the rate-determining step (*OH→*O). The migration of fluorine species and the infiltration of electrolyte combine to yield an increased number of active sites, improved conductivity and hydrophilicity, enhanced catalytic activity and durability.