The effect of cathodic treatment on the anodic polarization of copper sulfides

The oxidation states of copper and iron in mineral sulfides, and the oxides formed on initial exposure of chalcopyrite and bornite to air

“…8c) and S 2p photoelectron spectra from the mineral specimen examined by XAS in the present investigation were consistent with the covellite crystal structure and with a Cu(I) formal oxidation state, notwithstanding broad (presumably energy-loss) features on the high binding energy side of both the Cu 2p and S 2p peaks. No excited final state satellites that could have arisen from Cu(II) were evident in the Cu 2p spectrum, in agreement with previous investigations (e.g., Gebhardt et al, 1986;Perry and Taylor, 1986). The Cu 2p and O 1s photoelec- tron spectra and O K-edge spectrum indicated very little surface oxidation, consistent with the similarity in the TEY and TFY Cu L-edge NEXAFS spectra.…”

“…When determining bulk properties from NEXAFS spectra by monitoring the fluorescence yield (FY), the presence of oxidised species at the surface is less important because of the several hundred nm analysis depth for FY. Todd et al (2003b) tacitly assumed that covellite contained both Cu(I) and Cu(II), but they did not provide an explanation for the apparent absence of evidence for Cu(II) in the Cu 2p photoelectron spectra for unoxidised covellite and chalcopyrite (e.g., Folmer and Jellinek, 1980;Buckley and Woods, 1984;Gebhardt et al, 1986). Also, mackinawite, the Fe(II) reference sulfide studied by Todd et al (2003b), is known to be unstable in air (Boursiquot et al, 2001).…”

An assessment of silver copper sulfides for photovoltaic applications: theoretical and experimental insights

“…S6 and S7 † ), with the S 2p 3/2 peak measured at a binding energy of 161.5 eV in each case, consistent with expectations for S 2– ions. 69 After etching, no higher binding energy S 2p peaks, corresponding to sulfate species, were observed, indicating that any oxidation is limited to the surface.…”

“…Fig. S6 and S7 † (b) show the Cu 2p high resolution scans for AgCuS and Ag 3 CuS 2 , with Cu 2p 3/2 peaks at 932.5 eV (AgCuS) and 932.7 eV (Ag 3 CuS 2 ) corresponding to known values for Cu 2 S. 69 , 70 The Cu 2p peak shape is highly sensitive to Cu oxidation state, with Cu 2 + states displaying strong satellite features, and Cu metal showing asymmetry due to plasmon energy loss processes. Therefore the symmetric Cu 2p peaks observed here, and the absence of any satellite peaks, indicates that Cu + is the only copper oxidation state detected.…”

Durable Cu corrosion inhibition in acidic solution by SAMs of Benzenethiol

“…1d-f): after only 24 h ageing in H 2 SO 4 the percentage of chemisorbed thiol becomes less than 50% and as low as 35% after a week. It is worth noticing that in the alkylic SAM the amount of sulphonates (13.9%) is twice than that observed for BT (6.9%) and a new large component appears at 161.6 ± 0.1 eV in the S2p spectra, which indicates the formation of Cu 2 S on the surface [19]. This demonstrates that under these harsh conditions the S-C bonds in the alkylic SAMs are prone to breakage, whereas this does not happen in the BT layers.…”