Electrolysis of $50\%$ sulphuric acid is the commercial method for the preparation of hydrogen peroxide.
$ H_2SO_4 {<=>} H^+ + HSO_4^- $ .
At anode :
$2HSO_4^- \to H_2S_2O_8 + 2e^-$
$H_2S_2O_8 + 2H_2O \to 2H_2SO_4 + H_2O_2$
At cathode :
$2H + 2e^- \to H_2$