Digital.CSIC. Repositorio Institucional del CSIC

oai:digital.csic.es:10261/334306

Under a Creative Commons license CC-BY 4.0, Figure S 1. SEM images of (a) CoFe/NC10% , (b) CoFe/NC20% , and (c) CoFe/NC40%. Figure S 2.TEM images of (a) CoFe/NC10% , (b) CoFe/NC20% , and (c) CoFe/NC40%. Figure S 3. Particle size distribution of the various electrocatalyst: (a) CoFe2O4, (b) CoFe/NC10% , (c) CoFe/NC20% ,(d) CoFe/NC30% , and (e) CoFe/NC40% . Table S 1. Amount of CoFe alloys and oxides in the composite samples, determined from the XRD analysis. Figure S 4. XPS high resolution spectra of (a) Fe 2p, (b) Co 2p, for all electrocatalysts. Table S 2. XPS analysis results of the electrocatalysts. Table S 3. Elemental composition of the prepared electrocatalysts. Table S 4. Specific capacitance and ECSA values for the various eletrocataysts. Table S 5. Charge transfer resistance (Rct) and solution resistance (Rs) determined from EIS measurement. Figure S 5. ECSA-normalized polarization curve., Financial support from the European Union's Horizon 2020 Research and Innovation programme under the Marie Skłodowska-Curie Actions-Innovative Training Networks (MSCA-ITN) Grant Agreement 813748 are gratefully acknowledged. The authors wish to acknowledge the grants PID2020-115848RB-C21 and PID2020-115848RB-C22 funded by MCIN/AEI/10.13039/501100011033., Peer reviewed