Electrosorption, Desorption, and Oxidation of Perfluoroalkyl Carboxylic Acids (PFCAs) via MXene-Based Electrocatalytic Membranes

Qingquan Ma, Jianan Gao, Botamina Moussa, Joshua Young, Mengqiang Zhao, Wen Zhang

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

MXenes exhibit excellent conductivity, tunable surface chemistry, and high surface area. Particularly, the surface reactivity of MXenes strongly depends on surface exposed atoms or terminated groups. This study examines three types of MXenes with oxygen, fluorine, and chlorine as respective terminal atoms and evaluates their electrosorption, desorption, and oxidative properties. Two perfluorocarboxylic acids (PFCAs), perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) are used as model persistent micropollutants for the tests. The experimental results reveal that O-terminated MXene achieves a significantly higher adsorption capacity of 215.9 mg·g-1 and an oxidation rate constant of 3.9 × 10-2 min-1 for PFOA compared to those with F and Cl terminations. Electrochemical oxidation of the two PFCAs (1 ppm) with an applied potential of +6 V in a 0.1 M Na2SO4 solution yields >99% removal in 3 h. Moreover, PFOA degrades about 20% faster than PFBA on O-terminated MXene. The density functional theory (DFT) calculations reveal that the O-terminated MXene surface yielded the highest PFOA and PFBA adsorption energy and the most favorable degradation pathway, suggesting the high potential of MXenes as highly reactive and adsorptive electrocatalysts for environmental remediation.

Original languageEnglish (US)
Pages (from-to)29149-29159
Number of pages11
JournalACS Applied Materials and Interfaces
Volume15
Issue number24
DOIs
StatePublished - Jun 21 2023

All Science Journal Classification (ASJC) codes

  • General Materials Science

Keywords

  • DFT
  • MXene membrane
  • PFOA and PFBA
  • electrosorption
  • oxidation

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