Qualitative and quantitative analysis of chemical valence for cobalt by X-ray photoelectron spectroscopy

To identify valence state of cobalt is of significant in manufacturing battery of Ni-MH and Ni-Cd. There are seven 3d electrons in outermost shell of cobalt(II) and six electrons of cobalt(III). The cobalt (II) gives more intense shake-up satellite in the high spin state, while cobalt(III) is diamagnetic and has no satellite peak, so we can determine valence of cobalt and realize its quantitative analysis. Following equation X% = 100( 13 - 20C)/13(1 + C), (X% is the percent of cobalt(III), C is the ratio of shake-up satellite to primary peak in unknown sample of cobalt), gives approximately content of cobalt(III) in sample. And then we can identify hydroxide and oxide of cobalt (II) from the separation of the Co2p(1/2) peak and shake-up satellite to Co2p(1/2) primary peak.