The oxygen evolution reaction (OER) is the efficiency-determining half-reaction process of high-demand, electricity-driven water splitting due to its sluggish four-electron transfer reaction. Tremendous effects on developing OER catalysts with high activity and strong acid-tolerance at high oxidation potentials have been made for proton-conducting polymer electrolyte membrane water electrolysis (PEMWE), which is one of the most promising future hydrogen-fuel-generating technologies. Electrochemical water splitting involves two heterogeneous multi-step half-reactions, which are referred to as the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER). An important frontier in OER electrocatalysis research is the development of the rational design of catalysts. Most of the excellent OER catalysts with high activity and durability are not stable in acidic solutions. They are easily oxidized and decomposed in a strong acid system, which is one of the indispensable working conditions for PEMWE.  Outstanding OER electrocatalysts should have excellent intrinsic activity and sufficient active sites, and these requirements are generally combined with simplicity and controllability.