Fig. 3: Variations in catalyst structure and composition during potential pulse.
From: Steering the structure and selectivity of CO2 electroreduction catalysts by potential pulses
a, LCA-XANES analysis results (grey open circles) for averaged data for NCs under CO2RR with pulse lengths Δta = Δtc = 10 s, Ec = −1.0 V and Ea = 0.6 V. Results of EXAFS data fitting (filled black and red circles show the Cu(0) and total Cu(I) and Cu(II) concentrations extracted from Cu–Cu and Cu–O coordination numbers, respectively). Solid lines display the result of fitting concentration profiles for Cu(I) (red line) and Cu(II) (green line) with an analytical model. The concentration profile for Cu(II) is multiplied by 2 for clarity and to account for the twofold larger Cu–O coordination number in CuO than in the Cu2O bulk structure. Depicted error bars reflect the standard errors of LCA-XANES fitting results. The time dependencies of the potential E(t) and the current I(t) are also shown (vertical bars show the scale for different datasets). b, Evolution of the Cu(311) Bragg peak parameters. The relative changes in the Bragg peak area, the copper coherence length and the lattice strain are depicted. c, Evolution of the Cu2O-like Bragg peak parameters during the anodic pulse. The total area of the (111) and (220) Bragg peaks, average coherence length extracted from the (111) and (220) peak broadenings, and the lattice strain for the (111) and (220) lattice spacings are shown. The solid lines in b and c are guides for the eye (exponential fits).
