IrO₂ exhibits good stability but limited electrocatalytic activity for oxygen evolution reaction in acid. Defect engineering is an effective strategy to improve the intrinsic ability of electrocatalysts by tailoring their electronic structure. Herein, we have successfully synthesized IrO₂/Ir heterophase with compressive strain and metal vacancies via a simple substitution-etching method. In virtue of the solubility of Cr in strong alkali, metal vacancies could be formed at surface after etching Cr-doped IrO₂/Ir in alkali, which leaded to modulated electronic structure. Meanwhile, the substitution of Cr with smaller atom radius would induce the formation of compressive strain and the relocated atoms made the d-band center shifted. With the regulated electronic structure and tuned d-band center, the obtained electrocatalyst only needed 285 mV to reach 10 mA·cm⁻² in 0.1 M HClO₄. Reaction kinetic has been rapidly accelerated as indicated by the smaller Tafel slope and charge transfer resistance. Theoretical calculations revealed that the d-band center and charge density distribution have been regulated with the introduction of defects in IrO₂/Ir, which significantly decreased the free energy barrier of rate determining step. This work provides a valuable reference to design effective and defects-rich electrocatalysts.

IrO ₂表现出良好的稳定性，但对酸中析氧反应的电催化活性有限。缺陷工程是通过调整其电子结构来提高电催化剂内在能力的有效策略。在此，我们通过简单的置换蚀刻方法成功合成了具有压缩应变和金属空位的IrO _{2 /Ir 异相。}由于Cr在强碱中的溶解度，在蚀刻Cr掺杂的IrO _{2后可以在表面形成金属空位。}/Ir 在碱中，导致电子结构受调制。同时，原子半径较小的Cr的取代会引起压应变的形成，并且重新定位的原子使d带中心发生偏移。由于电子结构的调控和d带中心的调谐，所获得的电催化剂在0.1 M HClO ₄中仅需285 mV即可达到10 mA·cm ^-2。如较小的 Tafel 斜率和电荷转移电阻所示，反应动力学已迅速加速。_{理论计算表明，随着 IrO 2}中缺陷的引入，d 带中心和电荷密度分布得到了调节/Ir，显着降低了速率决定步骤的自由能垒。这项工作为设计有效且富含缺陷的电催化剂提供了有价值的参考。