Figure 5. (a) KIE of Co1-NC and
Co1-SNC measured at -0.8 V (vs. RHE). (b) Effect of
electrolyte pH on CO2RR performance over the
Co1-SNC at -0.8 V (vs. RHE). (c) EIS Nyquist plot of the
Co1-NC and Co1-SNC catalysts. (d)
Theoretically computed model of CoN4 and
CoN3S. (e) The calculated free energy diagrams of
CO2-to-CO conversion. (f) The calculated density of
states for Co 3d orbital of CoN4 and
CoN3S. (g) Differential charge density distribution
between the catalyst (CoN4 and CoN3S)
and *COOH intermediate.
Conclusions
In summary, Co1-SNC catalyst with a
Co1-N3S structure has been successfully
prepared through a facile pyrolysis method, which exhibits a greatly
enhanced CO2RR to CO performance compared to
Co1-NC. In situ ATR-SEIRAS and KIE analyses
demonstrate accelerated water dissociation over the
Co1-SNC catalyst. Furthermore, DFT calculations indicate
that the introduction of S into Co1-NC can adjust the
electronic structure of Co active center, facilitating the adsorption
and activation of CO2.
Experimental