We have performed density functional theory calculations to explore the possibility to overcome the linear scaling relations in the oxygen reduction reaction (ORR) using local inhomogeneities on Pt-based surface alloys, supported Pt monolayers, and Pt islands. We demonstrate that invoking inequivalent neighboring reaction sites allows overcoming the restrictions of one-dimensional linear scaling relations. As a consequence, the ORR activity at a (111) edge site of a Pt island on a Ru(0001) substrate outperforms the one on flat Pt(111). Furthermore, we show that it is critical to appropriately take the electrochemical environment into account, including the proper surface coverage and the presence of the electrolyte, which leads to microscopically modified ORR reaction schemes and a redetermination of the rate-limiting step.

中文翻译：

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铂基电极上的局部不均匀性和电化学环境对氧还原反应的影响：DFT研究

我们已经进行了密度泛函理论计算，以探索使用基于Pt的表面合金，负载的Pt单层和Pt岛上的局部不均匀性来克服氧还原反应（ORR）中线性比例关系的可能性。我们证明，调用不等价的相邻反应位点可以克服一维线性比例关系的限制。结果，Ru（0001）基板上Pt岛的（111）边缘部位的ORR活性优于平面Pt（111）上的ORR活性。此外，我们表明，至关重要的是要适当考虑电化学环境，包括适当的表面覆盖范围和电解质的存在，这会导致微观上修改的ORR反应方案和限速步骤的重新确定。