Self-Formed Double Tribolayers Play Collaborative Roles in Achieving Superlow Friction in an Aqueous Environment (J. Phys. Chem. C (2020) 124:15 (8295−8303) DOI: 10.1021/acs.jpcc.0c02068)

We have reinvestigated the assignment of the X-ray photoelectron spectroscopy (XPS) peaks in our original paper (Figure 2c). The original assignment, which was based on the available database, indicated that the amount of C-O-C/C-OH was much larger than that of SiO2 at the sliding interface of SiC in water. However, our subsequent simulation of the sliding interface of SiC in water based on first-principles molecular dynamics (MD) showed that the formation of C-O bonds is difficult compared to the formation of Si-O bonds.1 Moreover, a later reactive MD-based simulation of the sliding interface of SiC in water showed that the main product of the tribochemical reaction was SiO2, and there was little formation of C-O-C and C-OH.2 On the basis of these newly obtained simulation results, we decided to reinvestigate the XPS peaks. Figure 2c shows the XPS spectra with corrected peak assignments. Here, the binding energy was corrected for charge accumulation at the sample surface. No such correction was made in the original paper. The peak at 532.9 eV was assigned to SiO2, which is the main product of the tribochemical reaction.2 The peak at 533.7 eV could be assigned to H2O orCO2. However, because CO2 was not observed in the sliding simulations of SiC in water,2 we assigned the peak at 533.7 eV to H2O. The peak at 531.6 eV could be assigned to Si-OH, C-O-C, and C-OH, but because our sliding simulation showed that very little C-O-C and C-OH were formed,2 we assigned the peak at 531.6 eV to the Si.OH group, which is abundant at the sliding interface.2 According to a previous XPS study, the peak at 532.5 eV could be assigned to Si.O.C.3 Because our simulation of the sliding interface of SiC in water confirmed that considerable amounts of Si.O.C units were formed,2 we assigned the peak at 532.5 eV to Si.O.C. The main document should be corrected as follows: Page 8297, right column, the second line from the bottom: Several peaks corresponding to SiO2, Si.OH, and COC/COH were detected should read Several peaks corresponding to SiO2, Si.OH, and Si.O.C were detected. Page 8297, right column, the last line: Interestingly, we also detected a peak at ∼354 eV that corresponds to wateri± should read Interestingly, we also detected a peak at ∼534 eV that corresponds to water. These corrections do not affect the main conclusion that the second tribolayer contained water.