Electrocatalytic degradation of perfluorooctanoic acid by LaNixY1-xO3 (Y = Fe, Cu, Co, Sr) gas dispersion electrode

• Published in: Journal of fluorine chemistry 2021-02, Vol.242, p.109700, Article 109700
• Main Authors: Chen, Yongyang, Guo, Dan, Dong, Xiaochun, Li, Yahui, Huang, Yixuan, Chen, Hao, Li, Shanping
• Format: Article
• Language: English
• Subjects: Biodegradation; Carbon dioxide; Catalysts; Citric acid; Cobalt; Crystal structure; Current density; Defluorination; Degradation; Diffusion electrodes; Electrochemical analysis; Electrochemical degradation; Electrochemistry; Electrodes; Gas diffusion electrode; Gaseous diffusion; High performance liquid chromatography; Iron; LaNixY1-xO3 (Y= Fe, Cu, Co, Sr); Liquid chromatography; Mass spectrometry; Mass spectroscopy; Morphology; Oxidation; Perfluorooctanoic acid; Perfluorooctanoic acid (PFOA); Perovskites; pH effects; Pollutants; Sol-gel processes
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/j.jfluchem.2020.109700

[Display omitted] •A GDE doped with Sr had superior electrocatalytic properties.•A homemade GDE could enable the defluorination ratio of PFOA to reach 75.1 %.•The combined action of ·OH and O2 promoted the degradation of PFOA. Perfluorooctanoic acid (PFOA), as a refractory organic pollutant, seriously harms the environment and damages human health. Here, the electrocatalytic method was selected to degrade PFOA. In this work, perovskite catalysts doped with different elements, and corresponding gas diffusion electrodes (GDE) were prepared by the gel-sol method and citric acid complexation method. The crystal structure, microscopic morphology, and electrochemical properties of the LaNixY1-xO3 (Y = Fe, Cu, Co, Sr) perovskite catalyst electrode were analyzed by XRD, TEM, and CV. Moreover, the electrocatalytic performances of the as-prepared electrodes were assessed by the degradation of PFOA, and the Sr-doped GDE exhibited the highest degradation rate of PFOA. The optimum degradation conditions, such as the current density, pH, and initial concentration were also investigated. It was observed that when the current density was 20 mA/cm2, pH was 5, and initial concentration was 0.25 mmol/L, the Sr-doped GDE had the best degradation and defluorination efficiency of PFOA reached 90.0 % and 75.1 %, respectively. High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to analyze the intermediate products of PFOA degradation and obtain the degradation pathway. With the combined action of OH and O2, PFOA was degraded by stepwise removal of CF2 groups, which were ultimately degraded into F− and CO2.