Kuo Ding-Yuan, Paik Hanjong, Kloppenburg Jan, Faeth Brendan, Shen Kyle M, Schlom Darrell G, Hautier Geoffroy, Suntivich Jin
Department of Materials Science and Engineering , Cornell University , Ithaca , New York 14853 , United States.
Institute of Condensed Matter and Nanosciences (IMCN) , Université Catholique de Louvain , Louvain-la-Neuve 1348 , Belgium.
J Am Chem Soc. 2018 Dec 19;140(50):17597-17605. doi: 10.1021/jacs.8b09657. Epub 2018 Dec 10.
We report the hydroxide (OH) and oxide (O) experimental electroadsorption free energies, their dependences on pH, and their correlations to the oxygen evolution reaction (OER) electrocatalysis on RuO(110) surface. The Sabatier principle predicts that catalyst is most active when the intermediate stabilization is moderate, not too strong such that the bound intermediate disrupts the subsequent catalytic cycle, nor too weak such that the surface is ineffective. For decades, researchers have used this concept to rationalize the activity trend of many OER electrocatalysts including RuO, which is among the state-of-the-art OER catalysts. In this article, we report an experimental assessment of the Sabatier principle by comparing the oxygen electroadsorption energy to the OER electrocatalysis for the first time on RuO. We find that the OH and O electroadsorption energies on RuO(110) depend on pH and obey the scaling relation. However, we did not observe a direct correlation between the OH and O electroadsorption energies and the OER activity in the comparative analysis that includes both RuO(110) and IrO(110). Our result raises a question of whether the Sabatier principle can describe highly active electrocatalysts, where the kinetic aspects may influence the electrocatalysis more strongly than the electroadsorption energy, which captures only the thermodynamics of the intermediates and not yet kinetics.
我们报告了氢氧化物（OH）和氧化物（O）的实验性电吸附自由能、它们对pH值的依赖性以及它们与RuO(110)表面析氧反应（OER）电催化作用的相关性。萨巴蒂尔原理预测，当中间产物的稳定性适中时，催化剂最为活跃，既不能太强以至于结合的中间产物破坏后续的催化循环，也不能太弱以至于表面不起作用。几十年来，研究人员一直用这个概念来解释包括RuO在内的许多OER电催化剂的活性趋势，RuO是最先进的OER催化剂之一。在本文中，我们首次通过比较RuO上的氧电吸附能和OER电催化作用，对萨巴蒂尔原理进行了实验评估。我们发现，RuO(110)上的OH和O电吸附能取决于pH值并遵循标度关系。然而，在包括RuO(110)和IrO(110)的对比分析中，我们没有观察到OH和O电吸附能与OER活性之间存在直接相关性。我们的结果提出了一个问题，即萨巴蒂尔原理是否能够描述高活性电催化剂，在这种情况下，动力学因素可能比仅反映中间产物热力学而非动力学的电吸附能对电催化作用的影响更强。
