The double perovskite oxides are intriguing catalysts for energy conversion/storage and chemical sensor systems. The cation surface segregation is a stubborn issue that restricts their application. Herein, A-site cation size mismatch (M_A) was proposed for the first time as a critical intrinsic parameter for controlling the surface chemistry and electrochemical performance of the double perovskite catalyst. The studies in PrBa_1-xCa_xCoCuO_5+δ revealed that lowering M_A can relieve lattice distortion, enlarge PrO_δ layer space, maintain surface chemistry, and significantly improve catalytic activity and durability of the double perovskite. Specifically, as M_A decrease from 26.1 to 18.1%, the output peak power density of PrBa_1-xCa_xCoCuO_5+δ-based single-cells increase from 1.47 to 2.04 W cm^-2 (800 °C) while the output current density retentions rise from 82.2 to 94.7% after 100 hours (700 °C and 0.7 V). This guides the design of robust double perovskite catalysts in solid oxide cells, metal-air batteries, photocatalysis, and oxygen sensors.

钙钛矿双氧化物是用于能量转换/存储和化学传感器系统的催化剂。阳离子表面偏析是一个顽固的问题，限制了它们的应用。在本文中，A位阳离子尺寸不匹配（M_甲）提出了一种在第一时间作为用于表面化学和双钙钛矿催化剂的电化学性能控制的关键内部参数。在PrBa研究_1-X的Ca _X CoCuO _{5 +δ}透露，降低中号_阿可缓解晶格畸变，放大了PrO _δ层的空间，保持表面化学，和显著提高双钙钛矿的催化活性和耐久性。具体来说，如M _A从26.1％降低到18.1％，基于PrBa _1-x Ca _x CoCuO _{5 +δ}的单电池的输出峰值功率密度从1.47 W增加到2.04 W cm ^-2（800°C），而输出电流密度保持率从100小时（700°C和0.7 V）后，达到82.2至94.7％。这指导了固体氧化物电池，金属空气电池，光催化和氧气传感器中坚固的双钙钛矿催化剂的设计。