Fig. 6: Mechanistic studies.

a Surface potential distribution of hcp-Ru1Co, hcp/fcc-Ru1Co, and fcc-Ru1Co. b The corresponding surface potentials. c In situ ATR-SEIRAS spectra of hcp-Ru1Co at different potentials. d Online DEMS spectra of hcp-Ru1Co during the NO3RR process. e The PDOS profiles of hcp-Ru1Co, hcp/fcc-Ru1Co, and fcc-Ru1Co. The vertical dashed lines indicate the position of the d-band center. f and g The optimized structure models of hcp-Ru1Co (f) and fcc-Ru1Co (g). h and i 2D deformation charge density difference maps of hcp-Ru1Co (h) and fcc-Ru1Co (i). j The charge density difference of *NO3 adsorbed on hcp-Ru1Co, hcp/fcc-Ru1Co, and fcc-Ru1Co (electron accumulation and depletion are indicated by yellow and cyan regions, respectively). k The free energy diagrams of NO3RR over hcp-Ru1Co, hcp/fcc-Ru1Co, and fcc-Ru1Co. Source data for this figure are provided as a Source Data file.