Electrocatalytic reduction of CO2 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 capable to promote the electrocatalytic
CO2 reduction reaction (CO2RR). 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 CO2RR
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
CO2RR chemistry over heteroatom-doped SACs for designing
efficient CO2RR processes.
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