The electrochemical reduction of
CO2 to produce carbon-based
fuels and chemicals possesses huge potentials to alleviate current
environmental problems. However, it is confronted by great challenges
in the design of active electrocatalysts with low overpotentials and
high product selectivity. Here we report the atomic tuning of a single-Fe-atom
catalyst with phosphorus (Fe–N/P–C) on commercial carbon
black as a robust electrocatalyst for CO2 reduction. The
Fe–N/P–C catalyst exhibits impressive performance in
the electrochemical reduction of CO2 to CO, with a high
Faradaic efficiency of 98% and a high mass-normalized turnover frequency
of 508.8 h–1 at a low overpotential of 0.34 V. On
the basis of ex-situ X-ray absorption spectroscopy
measurements and DFT calculations, we reveal that the tuning of P
in single-Fe-atom catalysts reduces the oxidation state of the Fe
center and decreases the free-energy barrier of *CO intermediate formation,
consequently maintaining the electrocatalytic activity and stability
of single-Fe-atom catalysts.