Heterobimetallic praseodymium-nickel active sites with Pr-N4C2 and Ni-N4 moieties enabling synergistic catalysis of CO2 electroreduction

Lanthanide metals have attracted particular interest in the catalysis of electrochemical CO2 reduction. The synthesis and precise spatial distribution of active sites are fundamental important but still formidably challenging owing to the strong oxygen affinity of lanthanide. Here, heteronuclear Pr1-Ni1 single atoms are supported on the carbon matrix containing surface framework defects from lanthanide contraction. The Pr/Ni-NC catalyst exhibits a CO Faradaic efficiency of 99.1 % with a commercial-scale current density of 237 mA cm−2 and a turnover frequency as high as 18,038 h−1 at −1.1 V due to d-f coupling effect and electronic structure perturbation of Pr. Furthermore, mechanistic investigations unveil that the diatomic active sites effectively reduce the energy barrier of the crucial *COOH formation, in which the Pr site facilitates CO2 activation and the Ni site enables H2O dissociation to accelerate the proton transfer process, thereby ensuring the synergy of catalytic sites to greatly facilitate CO2-to-CO conversion.