Perfluoroalkyl substances (PFAS), used in commercial coatings and as essential components of firefighting foams, have been identified by the U.S. Environmental Protection Agency as pervasive environmental contaminants that bioaccumulate and pose a potentially serious health risk. The robust chemical stability of PFAS severely impedes their natural degradation, and light PFAS are not effectively removed by conventional water filtration technology. Degradation of PFAS by electrochemical reduction with solvated electrons could provide an efficient and clean pathway to purify water containing PFAS. Hydrogen-terminated diamond surfaces are known to exhibit a negative electron affinity (NEA), and solvated electrons photochemically produced at illuminated H-terminated diamond interfaces have been demonstrated to reduce N2 to NH3 and CO2 to CO in water. In this work, hydride-, amino-, and alkyl-terminated diamond surfaces, all of which exhibit NEA, are prepared, and their respective vibrational and electronic structures are determined. The behavior of the electron affinity as a function of gradual oxidation of the surface in air and in aqueous environments is investigated. The suitability of diamond electrodes terminated by hydride, amino, and alkyl substituents as sources of solvated electrons for the purification of water contaminated by PFAS will be discussed.

Negative electron affinity diamond surfaces for photoelectrochemical reduction of perfluoroalkyl substances

254th National Meeting (2017)

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