Fig. 4: The competitive adsorption of H₂O and NO₂^-.

The radical density of NO₂⁻ and H₂O over the surface of A Cu₂O(111) and B Cu(111) catalyst model. C The IR peak position shift under various potentials during both the pulsed electrolysis at E_P = 0.8 V and the potentiostatic electrolysis. D H₂ signals under the pulsed electrolysis at E_P = 0.8 V and the potentiostatic electrolysis were detected by online DEMS. E The potentials required to attain a current density of −1 mA cm⁻² and the reaction rate constants under varying E_P conditions in the pulsed and potentiostatic electrolysis. The note (E_P = 0.4 V, E_P = 0.6 V, and E_P = 0.8 V) stood for the Cu nanoparticles that experienced an hour pulsed reduction at E_P = 0.4 V, E_P = 0.6 V, and E_P = 0.8 V, respectively. Error bars denote standard deviations based on three independent measurements. The voltage is not iR corrected. Source data for the figure are provided as a Source data file.