The formed amorphous structures were well recognized to exhibit relatively better OER electrocatalytic activity, compared with their crystalline counterparts, as they possess more undercoordinated sites , facilitating the adsorption/desorption of intermediates during the OER process; or amorphous catalysts would also undergo a rapid self-reconstruction during OER and produce a metal oxy(hydroxide) layer with rich O-vacancies. Nevertheless, compared with crystalline ones, amorphous structures are often less stable when exposed to highly corrosive and oxidative environments. Also importantly, the intrinsic structureactivity relationship during the OER process remained unclear due to the difficulty in confirming the active phase structure of amorphous phases. Therefore, well-crystalline electrocatalysts still show great promise in both the long-term stability and fundamental understanding of electrocatalytic OER.