“…And the higher content of e g state in LDH-Sx contributed to the lower valence states of Ni in LDH-Sx as the previous work reported. [24] By comparison, the intensities of e g state of LDH-S1 and LDH-S3 were weaker than that of LDH-S2 due to more O vacancies in LDH-S2. [25,26] In addition, the peaks at ≈536.4 eV, 539.4 eV, and 543.3 eV (marked as B, C, and D) were ascribed to O 2p states hybridized with Ni 4sp states.…”