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, Accepted manuscript online, 2020.

J. Noel, *. N. Kostopoulos, C. Achaibou, C. Fave, and . &&&&-&&&&,

, Catalysts in action: Scanning electrochemical microscopy was used to quantitatively analyze O 2 reductive activation in organic media catalyzed by three different Fe porphyrins. In one single experiment the redox potential of various intermediates, the association constant of Fe II with O 2 , and the pK a of the Fe III