Heterobimetallic praseodymium-nickel active sites with Pr-N4C2 4 C 2 and Ni-N4 4 moieties enabling synergistic catalysis of CO2 2 electroreduction

Lanthanide metals have attracted particular interest in the catalysis of electrochemical CO2 2 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 1-Ni 1 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 2 activation and the Ni site enables H2O 2 O dissociation to accelerate the proton transfer process, thereby ensuring the synergy of catalytic sites to greatly facilitate CO2-to-CO 2-to-CO conversion.