fig4

Figure 4. Identification of the interfacial water structure. In situ FTIR spectra of (A) Cu-MoS₂ under applied potentials from 0 to -0.6 V vs. RHE and (B) CuO-MoS₂/MoO₃ under applied potentials from 1.0 to 1.6 V vs. RHE; The Gaussian fits of three O-H stretching modes on (C) Cu-MoS₂ and (D) CuO-MoS₂/MoO₃; Potential-dependent population of the three water species on (E) Cu-MoS₂ and MoS₂ and (F) CuO-MoS₂/MoO₃ and MoS₂/MoO₃; (G) The corresponding wavenumber shift of symmetric H₂O over Cu-MoS₂ and MoS₂, and CuO-MoS₂/MoO₃ and MoS₂/MoO₃.