Fig. 2: In situ characterization of the oxygen evolution behavior on Ni-based hydroxides in 0.1 M KOH. | Nature Communications

Fig. 2: In situ characterization of the oxygen evolution behavior on Ni-based hydroxides in 0.1 M KOH.

From: Sequential oxygen evolution and decoupled water splitting via electrochemical redox reaction of nickel hydroxides

Fig. 2

a CVs (red lines) of the Ni(OH)2/C catalyst in 0.1 M KOH scanned to different UPLs (I, 1.60 V; II, 1.50 V; III, 1.45 V) at a scanning rate of 1 mV s−1 and the operando DEMS signals of O2 (m/z = 32, blue lines) using a commercial double thin layer flow cell. b Comparison of CVs and operando DEMS signals of O2 on the Ni(OH)2/C, the Ni(OH)2/C–120, and the Fe–Ni(OH)2/C catalyst formed by adsorbing Fe from 0.1 M KOH containing 0.1 mM Fe(NO3)3. The inset shows schematically the formation of Fe–Ni(OH)2/C catalyst. c Faradaic current density-time curve (j-t, red lines) of the Ni(OH)2/NiOOH redox reaction on the Ni(OH)2/C catalyst and the operando DEMS signal of O2 (blue lines). The left panel shows the signals for a whole Ni(OH)2/NiOOH redox cycle, while in the right figure, the potential control was withdrawn after reaching 1.45 V, with the open circuit potential recorded during the reduction process. The potential-time curves (E-t, black line) during the processes are shown to identify the specific emerging potential of the ACS-OER and the chemical OER process. Source data are provided as a Source Data file.

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