Beheshti Askari Abbas, Al Samarai Mustafa, Morana Bruno, Tillmann Lukas, Pfänder Norbert, Wandzilak Aleksandra, Watts Benjamin, Belkhou Rachid, Muhler Martin, DeBeer Serena
Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr D-45470, Germany.
NanoInsight, Feldmannweg 17, 2628 CT Delft, The Netherlands.
ACS Catal. 2020 Jun 5;10(11):6223-6230. doi: 10.1021/acscatal.9b05517. Epub 2020 May 1.
Herein, we report the synthesis of a γ-AlO-supported NiCo catalyst for dry methane reforming (DMR) and study the catalyst using in situ scanning transmission X-ray microscopy (STXM) during the reduction (activation step) and under reaction conditions. During the reduction process, the NiCo alloy particles undergo elemental segregation with Co migrating toward the center of the catalyst particles and Ni migrating to the outer surfaces. Under DMR conditions, the segregated structure is maintained, thus hinting at the importance of this structure to optimal catalytic functions. Finally, the formation of Ni-rich branches on the surface of the particles is observed during DMR, suggesting that the loss of Ni from the outer shell may play a role in the reduced stability and hence catalyst deactivation. These findings provide insights into the morphological and electronic structural changes that occur in a NiCo-based catalyst during DMR. Further, this study emphasizes the need to study catalysts under operating conditions in order to elucidate material dynamics during the reaction.
在此，我们报告了一种用于干甲烷重整（DMR）的γ -AlO负载型NiCo催化剂的合成，并使用原位扫描透射X射线显微镜（STXM）在还原过程（活化步骤）和反应条件下对该催化剂进行了研究。在还原过程中，NiCo合金颗粒发生元素偏析，Co向催化剂颗粒中心迁移，Ni迁移到外表面。在DMR条件下，偏析结构得以维持，这暗示了该结构对最佳催化功能的重要性。最后，在DMR过程中观察到颗粒表面形成了富Ni分支，这表明外壳中Ni的损失可能在稳定性降低以及催化剂失活中起作用。这些发现为DMR过程中NiCo基催化剂发生的形态和电子结构变化提供了见解。此外，本研究强调了在操作条件下研究催化剂以阐明反应过程中材料动态变化的必要性。
