Surface site density and utilization of platinum group metal (PGM)-free Fe-NC and FeNi-NC electrocatalysts for the oxygen reduction reaction.

ABSTRACT: Pyrolyzed iron-based platinum group metal (PGM)-free nitrogen-doped single site carbon catalysts (Fe-NC) are possible alternatives to platinum-based carbon catalysts for the oxygen reduction reaction (ORR). Bimetallic PGM-free M₁M₂-NC catalysts and their active sites, however, have been poorly studied to date. The present study explores the active accessible sites of mono- and bimetallic Fe-NC and FeNi-NC catalysts. Combining CO cryo chemisorption, X-ray absorption and ⁵⁷Fe Mössbauer spectroscopy, we evaluate the number and chemical state of metal sites at the surface of the catalysts along with an estimate of their dispersion and utilization. Fe L_3,2-edge X-ray adsorption spectra, Mössbauer spectra and CO desorption all suggested an essentially

SUBMITTER: Luo F 

PROVIDER: S-EPMC8179675 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature