Simultaneously improving the activity and stability of catalysts for anodic oxygen evolution reaction (OER) in proton exchange membrane water electrolysis (PEMWE) remains a notable challenge. Here, we report a chromium-doped ruthenium dioxide with oxygen vacancies, termed Cr_0.2Ru_0.8O_2-x, that drives OER with an overpotential of 170 mV at 10 mA cm⁻² and operates stably over 2000 h in acidic media. Experimental and theoretical studies show that the synergy of Cr dopant and oxygen vacancy induces an unconventional dopant-mediated hydroxyl spillover mechanism. Such dynamic hydroxyl spillover from Cr dopant to Ru active site changes the rate-determining step from OOH* formation to O₂ formation and thus greatly improves the OER performance. Moreover, the Cr dopant and oxygen vacancy also play a crucial role in stabilizing surface Ru and lattice oxygen in the Ru-O-Cr structural motif. When assembled into the anode of a practical PEMWE device, Cr_0.2Ru_0.8O_2-x enables long-term durability of over 200 h at an ampere-level current density and 60 degrees centigrade.

同时提高质子交换膜水电解（PEMWE）中阳极析氧反应（OER）催化剂的活性和稳定性仍然是一个显着的挑战。在这里，我们报道了一种带有氧空位的铬掺杂二氧化钌，称为Cr _0.2 Ru _0.8 O _2-x ，它在10 mA cm ^-2下以170 mV的过电势驱动OER，并在酸性介质中稳定运行超过2000小时。实验和理论研究表明，Cr掺杂剂和氧空位的协同作用诱导了非常规掺杂剂介导的羟基溢出机制。这种从Cr掺杂剂到Ru活性位点的动态羟基溢出改变了从OOH*形成到O ₂形成的速率决定步骤，从而极大地提高了OER性能。此外，Cr掺杂剂和氧空位对于稳定Ru-O-Cr结构基序中的表面Ru和晶格氧也起着至关重要的作用。当组装到实际PEMWE装置的阳极中时，Cr _0.2 Ru _0.8 O _2-x能够在安培级电流密度和60摄氏度下实现超过200小时的长期耐久性。