Tuning the surface structure at the atomic level is of primary importance to simultaneously meet the electrocatalytic performance and stability criteria required for the development of low-temperature proton-exchange membrane fuel cells (PEMFCs). However, transposing the knowledge acquired on extended, model surfaces to practical nanomaterials remains highly challenging. Here, we propose ‘surface distortion’ as a novel structural descriptor, which is able to reconciliate and unify seemingly opposing notions and contradictory experimental observations in regards to the electrocatalytic oxygen reduction reaction (ORR) reactivity. Beyond its unifying character, we show that surface distortion is pivotal to rationalize the electrocatalytic properties of state-of-the-art of PtNi/C nanocatalysts with distinct atomic composition, size, shape and degree of surface defectiveness under a simulated PEMFC cathode environment. Our study brings fundamental and practical insights into the role of surface defects in electrocatalysis and highlights strategies to design more durable ORR nanocatalysts.

在原子水平上调节表面结构对于同时满足开发低温质子交换膜燃料电池（PEMFC）所需的电催化性能和稳定性标准至关重要。但是，将在扩展的模型表面上获得的知识转换为实用的纳米材料仍然非常具有挑战性。在这里，我们提出“表面变形”作为一种新颖的结构描述词，它能够调和和统一看似相反的概念以及与电催化氧还原反应（ORR）反应性相矛盾的实验观察结果。除了其统一的特征外，我们还表明，表面畸变对于合理化具有不同原子组成，尺寸，在模拟PEMFC阴极环境下的形状和表面缺陷程度。我们的研究为表面缺陷在电催化中的作用带来了基础性和实践性的见解，并着重介绍了设计更耐用的ORR纳米催化剂的策略。