$Ce ^{+4}+ e ^{-} \rightarrow Ce ^{3+} \,\quad\quad\,\,\, E ^{0}=+1.61 \,V$

$Ce ^{+3}+3 e ^{-} \rightarrow Ce \quad\quad\,\,\, E ^{0}=-2.336 \,V$

It shows $Ce ^{+4}$ acts as a strong oxidising agent $\&$ accepts electron.