Besides, because electrochemical conditions will induce water activation or generation (which would lead to the formation of HO*/O*/H* or anion vacancy on the surface), analyzing the electrochemistry-induced surface state (i.e., the coverage of an electrocatalyst under electrochemical conditions) is essential. An electrochemical environment would lead to the poisoning of a reactive site, change of a surface's electronic structure, or the formation of new active site, which would lead to a very different mechanistic understanding compared to the activity analysis over a stoichiometric pristine surface. However, this is an often-dismissed process in electrocatalyst design and understanding. To provide better understandings to an electrocatalyst, surface Pourbaix diagram analysis