“…15,43 The peak at 532.7 eV was assigned to the H 2 O molecules, which were physically and chemisorbed on the structural surface. 7,44 Noticeably, the strong peak at 531.5 eV was attributed to the typical bonds between metal and -OH (denoted as M-OH, M = Co, Ni, Fe). 25,45 Accordingly, the contents of M-OH, M-O, and H 2 O were determined to be 66.9%, 7.1%, and 26%, respectively, indicating that the M-OH was dominant.…”