Remote p–d orbital hybridization via first/second-layer coordination of Fe single atoms with heteroatoms for enhanced electrochemical CO2-to-CO reduction

d–p orbital hybridization induced by S/N in the coordination layer of pyrrole-type Fe–N 4 can modulate the electronic structure of Fe single atoms, enabling *COOH adsorption and *CO desorption to exclusively furnish CO but suppressing H 2 formation.