“…The peak at 530.6 eV corresponds to Y 2 O 3 [15], the binding energy at 531.6 eV is attributed to MgO [14], and the other two peaks at 532.6 eV and 533.3 eV are attributed to OH − ion and CO 3 2− , respectively [14,16,17]. The Y 3d spectrum exhibits two peaks due to the spin orbit splitting into Y 3d 3/2 and Y 3d 5/2 components [16]: one at 159.1 eV and another peak at 157.7 eV. These values are in agreement with the value of Y 2 O 3 [16,18].…”