Article
Extended Data Fig. 2 | Comparison of anti-corrosion performance of
Cu-FA with Cu foils with other corrosion inhibitors. a, Electrochemical
characterizations of Cu-FA foil and Cu foils treated with DT and BTA corrosion
inhibitors. Whereas all measurements were carried out in 0.1 M NaOH, the
Nyquist impedance and Bode plots were recorded at 0.1 V versus Ag/AgCl. The
polarization parameters of Cu foils with different surface treatments in 0.1 M
NaOH are: Ecorr = −21 2 mV, Jcorr = 5.1 2 μ A cm−2, corrosion rate 59.7 μm yr−1,
anti-corrosion factor 1.31 (Cu-BTA); Ecorr = −210 mV, Jcorr = 4. 33 μ A cm−2, corrosion
rate 50.4 μm yr−1, anti-corrosion factor 1.55 (Cu-DT). For comparison, the
anti-corrosion factor of Cu-FA in 0.1 M NaOH is 20.1. b, Tafel and Nyquist plots,
SEM images and Raman spectra of the samples before and after the
electrochemical measurements. The Nyquist plots were measured at 0.1 V
versus Ag/AgCl in 1 M NaOH. The Raman bands at 297 cm−1 and 623 cm−1 come
from CuO species^68. Owing to the concentration difference, the Tafel plot of
Cu-FA in 1 NaOH displays a minimum that is different from that in 0.1 M NaOH.
The polarization parameters of Cu foils before and after the formate treatment
in 1.0 M NaOH are: Ecorr = −2 81 mV, Jcorr = 59.7 μ A cm−2, corrosion rate 695.8 μm yr−1
(bare Cu); Ecorr = −31 1 mV, Jcorr = 5.10 μ A cm−2, corrosion rate 59.4 μm yr−1 (Cu - FA ),
anti-corrosion factor 11.7. The anti-corrosion factor is defined as the ratio of the
corrosion rate bare Cu foil to that of modified Cu in 1 NaOH. c, SEM images of
bare Cu and Cu-FA (prepared by Method II) foils after exposure to 30% H 2 O 2 for
0, 5 and 15 min. d, Optical images of Cu-FA (prepared by Method II) and
untreated Cu foils before and after heating at 160 °C in air for 1 h and
corresponding Raman spectra after thermal treatment. e, Localized corrosion
of Cu-FA monitored by SRET/STM. The three-dimensional corrosion current
maps were recorded on scratched Cu-FA and bare Cu foils after immersion in
0.1 M NaOH for 5, 30 and 90 min, and SEM images before and after the
SRET/STM test were taken to identify the oxidized area.