Current understandings of the sluggish kinetics of the hydrogen evolution and oxidation reactions in base

The hydrogen evolution and oxidation reactions (HER/HOR) in alkaline media are the most fundamental electrochemical reactions in alkaline electrochemistry. Surprisingly, their kinetics is still elusive and under extensive debates. Herein, a critical review of the four schools of thoughts of the alkaline HER/HOR kinetics is given, focusing on the key discrepancies in the underlying mechanisms and experimental supports within these thoughts.