Fig. 5: Reaction pathway.

In-situ ATR-SEIRAS spectra recorded over Co/Co3O4/CoB a and Co/Co3O4 b in 0.1 M PBS at the applied cathodic potential from OCP to −0.7 V vs. RHE. c Online DEMS measurement results over Co/Co3O4/CoB at −0.5 V vs. RHE. d The calculated NORR Gibbs free energy diagrams over Co/Co3O4 and Co/Co3O4/CoB at 0 V vs. RHE. Atom color-coding: Purple, cobalt; red, oxygen; orange, nitrogen; gray, hydrogen. e Schematic illustration showing the NORR mechanism over Co/Co3O4/CoB electrocatalyst. Atom color-coding: Light blue, cobalt; pink, boron; red, oxygen; deep blue, nitrogen; gray, hydrogen. Source data for Fig. 5 are provided as a Source Data file.