Several metals having high hydrogen overoptential, such as Sn、Bi、Ni、Zn and Cu, were used to modify Pb electrode, and the modified electrodes were used in the electrosynthesis of L cysteine. First of all the electrdes modified with Sn、Ni and Zn with better performance were selected, then the alloy modified electrodes of these three kinds of metals were studied. It was found that electrode modified with Ni Sn had the best performance, the activity of electrode was greatly enhanced, the conversion increased ...