Hosting
atomically dispersed nitrogen-coordinated iron sites (Fe–N4) on graphene offers unique opportunities for driving electrochemical
CO2 reduction reaction (CO2RR) to CO. However,
the strong adsorption of *CO on the Fe–N4 site embedded
in intact graphene limits current density due to slow CO desorption
process. Herein, we report how the manipulation of pore edges on graphene
alters the local electronic structure of isolated Fe–N4 sites and improves their intrinsic reactivity for prompting
CO generation. We demonstrate that constructing holes on graphene
basal plane to support Fe–N4 can significantly enhance
its CO2RR compared to the pore-deficient graphene-supported
counterpart, exhibiting a CO Faradaic efficiency of 94% and a turnover
frequency of 1630 h–1 at 0.58 V vs RHE. Mechanistic
studies reveal that the incorporation of pore edges results in the
downshifting of the d-band center of Fe sites, which weakens the strength
of the Fe–C bond when the *CO intermediate adsorbs on edge-hosted
Fe–N4, thus boosting the CO desorption and evolution
rates. These findings suggest that engineering local support structure
renders a way to design high-performance single-atom catalysts.
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