Dupraz Maxime, Li Ni, Carnis Jérôme, Wu Longfei, Labat Stéphane, Chatelier Corentin, van de Poll Rim, Hofmann Jan P, Almog Ehud, Leake Steven J, Watier Yves, Lazarev Sergey, Westermeier Fabian, Sprung Michael, Hensen Emiel J M, Thomas Olivier, Rabkin Eugen, Richard Marie-Ingrid
Univ. Grenoble Alpes, CEA Grenoble, IRIG, MEM, NRS, 17 rue des Martyrs, 38000, Grenoble, France.
ESRF - The European Synchrotron, 71 Avenue des Martyrs, Grenoble, 38000, France.
Nat Commun. 2022 May 30;13(1):3003. doi: 10.1038/s41467-022-30592-1.
Nanostructures with specific crystallographic planes display distinctive physico-chemical properties because of their unique atomic arrangements, resulting in widespread applications in catalysis, energy conversion or sensing. Understanding strain dynamics and their relationship with crystallographic facets have been largely unexplored. Here, we reveal in situ, in three-dimensions and at the nanoscale, the volume, surface and interface strain evolution of single supported platinum nanocrystals during reaction using coherent x-ray diffractive imaging. Interestingly, identical {hkl} facets show equivalent catalytic response during non-stoichiometric cycles. Periodic strain variations are rationalised in terms of O adsorption or desorption during O exposure or CO oxidation under reducing conditions, respectively. During stoichiometric CO oxidation, the strain evolution is, however, no longer facet dependent. Large strain variations are observed in localised areas, in particular in the vicinity of the substrate/particle interface, suggesting a significant influence of the substrate on the reactivity. These findings will improve the understanding of dynamic properties in catalysis and related fields.
具有特定晶面的纳米结构由于其独特的原子排列而表现出独特的物理化学性质，从而在催化、能量转换或传感等领域得到广泛应用。然而，对应变动力学及其与晶面的关系的理解在很大程度上尚未得到探索。在这里，我们利用相干X射线衍射成像技术，在三维空间和纳米尺度上原位揭示了单个负载型铂纳米晶体在反应过程中的体积、表面和界面应变演化。有趣的是，相同的{hkl}晶面在非化学计量循环中表现出等效的催化响应。周期性应变变化分别根据在O暴露期间的O吸附或在还原条件下的CO氧化期间的O解吸来解释。然而，在化学计量的CO氧化过程中，应变演化不再依赖于晶面。在局部区域观察到较大的应变变化，特别是在基底/颗粒界面附近，这表明基底对反应性有显著影响。这些发现将增进对催化及相关领域动态性质的理解。
