Figure 5.

(a) LSV curves of N−C, NS−C, Ni−N−C, and Ni−NS−C catalysts under CO₂‐saturated 0.5 m KHCO₃ solution at a scan rate of 10 mV s⁻¹; (b) LSV curves of Ni−NS−C catalyst under N₂‐ and CO₂‐saturated 0.5 m KHCO₃ solution at a scan rate of 10 mV s⁻¹; (c) faradaic efficiencies of CO generation and (d) faradaic efficiencies of H₂ generation on N−C, NS−C, Ni−N−C, and Ni−NS−C catalysts; (e) Charging current density differences against scan rates over N−C, NS−C, Ni−N−C, and Ni−NS−C catalysts; (f) relationship between double layer capacity and BET surface area of the N−C, NS−C, Ni−N−C, and Ni−NS−C catalysts.