Fig. 3: Identification of the configuration of N and Ru species in single atom Ru-supported (Ru SA)-rGO.

a Schematic diagram showing the configuration of nitrogen species doped into rGO lattice. b XPS C 1 s spectra of SAM, N-rGO/SAM, and Ru SA-rGO/SAM (from top to bottom). c XPS N 1 s spectra of SAM, N-rGO/SAM, and Ru SA-rGO/SAM (from top to bottom). d The optimized structures and the adsorption energies for Ru-pyridinic N, Ru-pyrrolic N and Ru-graphitic N configurations. The structures were optimized by DFT calculations within the generalized gradient approximation and GGA-PBE approximation, as implemented in the VASP package. Source data are provided as a Source Data file.