Standard Half-Cell Reduction Potential for Periodate to Iodine
Here is the standard half-cell reduction potential $\ce{IO4^{−}/I2}$ in acid medium depicted using Latimer diagram.



(source)

Note: Here $\ce{IO4-}$ (periodate ion) gets hydrated to form orthoperiodic acid which is $\ce{HIO4.2H2O}$  or $\ce{H5IO6}$.