Fig. 4: Operando XAFS investigation of the structural evolution.

a Ni K-edge, c Fe K-edge, and e Ru K-edge XANES spectra under different operation potentials. FT-EXAFS curves of b Ni K-edge, d Fe K-edge, and f Ru K-edge displayed at R space at above potentials. WT-EXAFS plots of g Ni, h Fe, and i Ru K-edge at OCV and 1.5 V (vs RHE).