Promoting Electrocatalytic CO_(2) Reduction to CO via Sulfur-Doped Co-N-C Single-Atom Catalyst

Electrocatalytic reduction of CO_(2) to fuels and chemicals possesses huge potential to alleviate current environmental crisis.Heteroatom doping in metal-nitrogen-carbon(M-N-C)single-atom catalysts(SACs)has been found to be capable to promote the electrocatalytic CO_(2) reduction reaction(CO_(2)RR).However,the origin of the enhanced activity is still elusive.Here,we report that sulfur-doped cobalt-nitrogen-carbon single-atom catalyst(Co1-SNC)exhibits superior CO_(2)RR performance compared to sulfur-free counterpart(Co1-NC).On the basis of in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS),kinetic isotope effect(KIE)and theoretical calculation,it is demonstrated that sulfur doping can promote water activation,elevate the d-band center of Co active site,and reduce the free energy of*COOH intermediate formation.This work deepens the understanding of the CO_(2)RR chemistry over heteroatom-doped SACs for designing efficient CO_(2)RR processes.