Revealing the Origin of Low‐Temperature Activity of Ni–Rh Nanostructures during CO Oxidation Reaction with Operando TEM. Issue 17 (5th May 2022)

• Record Type: Journal Article
• Authors: Ghosh, Tanmay; Liu, Xiangwen; Sun, Wenming; Chen, Meiqi; Liu, Yuxi; Li, Yadong; Mirsaidov, Utkur
• Is Part Of: Advanced science. Volume 9:Issue 17(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-05
• Subjects: CO oxidation -- heterogeneous catalysis -- nanoparticles -- operando TEM; Science -- Periodicals; 505
• DOI: 10.1002/advs.202105599
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: In bimetallic heterostructured nanoparticles (NPs), the synergistic effect between their different metallic components leads to higher catalytic activity compared to the activity of the individual components. However, how the dynamic changes through which these NPs adopt catalytically active structures during a reaction and how the restructuring affects their activity are largely unknown. Here, using operando transmission electron microscopy, structural changes are studied in bimetallic Ni–Rh NPs, comprising of a Ni core whose surface is decorated with smaller Rh NPs, during a CO oxidation reaction. The direct atomic‐scale imaging reveals that, under O2 ‐rich conditions, Ni core partially transforms into NiO, forming a (Ni+NiO)–Rh hollow nanocatalyst with high catalytic activity. Under O2 ‐poor conditions, Rh NPs alloy with the surface of the core to form a NiRh‐alloy surface, and the NPs display significantly lower activity. The theoretical calculations indicate that NiO component that forms only under O2 ‐rich conditions enhances the activity by preventing the CO poisoning of the nanocatalysts. The results demonstrate that visualizing the structural changes during reactions is indispensable in identifying the origin of catalytic activity. These insights into the dynamic restructuring of NP catalysts under a reactive environment are critical for the rational design of high‐performance nanocatalysts. Abstract : Using operando transmission electron microscopy, this study tracks individual bimetallic Ni–Rh nanoparticles (NPs) during a CO oxidation reaction in real‐time and reveals the details of the NPs' dynamic structure responsible for their low‐temperature catalytic activity. Namely, the interface between Rh and newly formed NiO significantly reduces the CO poisoning of Rh at low temperatures boosting its activity.