Table 2: Surface atomic concentrations of various elements acquired with XPS.

SampleCeTiOKClS

Ce/TiO21.8631.6066.54
Ce/TiO2-KNO3-0.252.0132.2265.000.76
Ce/TiO2-KCl-0.252.1331.4964.920.990.47
Ce/TiO2-K2SO4-0.252.2930.4164.431.761.11