A Discovery of Strong Metal-Support Bonding in Nanoengineered Au-Fe3O4 Dumbbell-like Nanoparticles by in Situ Transmission Electron Microscopy

作者：Han, Chang Wan; Choksi, Tej; Milligan, Cory; Majumdar, Paulami; Manto, Michael; Cui, Yanran; Sang, Xiahan; Unocic, Raymond R.; Zemlyanov, Dmitry; Wang, Chao; Ribeiro, Fabio H.; Greeley, Jeffrey; Ortalan, Volkan^*

来源：Nano Letters, 2017, 17(8): 4576-4582.

DOI：10.1021/acs.nanolett.7b00827

• Heterogeneous catalysis
• gold catalyst
• metal-support interaction
• electron microscopy
• density functional theory

The strength of metal support bonding in heterogeneous catalysts determines their thermal stability, therefore, a tremendous amount of effort has been expended to understand metal-support interactions. Herein, we report the discovery of an anomalous "strong metal-support bonding" between gold nanoparticles and "nano-engineered" Fe3O4 substrates by in situ microscopy. During in situ vacuum annealing of Au Fe3O4 dumbbell-like nanoparticles, synthesized by the epitaxial growth of nano-Fe3O4 on Au nanoparticles, the gold nanoparticies transform into the gold thin films and wet the surface of nano-Fe3O4, as the surface reduction of nano-Fe3O4 proceeds. This phenomenon results from a unique coupling of the size-and shape-dependent high surface reducibility of nano-Fe3O4 and the extremely strong adhesion between Au and the reduced Fe3O4. This strong metal support bonding reveals the significance of controlling the metal oxide support size and morphology for optimizing metal support bonding and ultimately for the development of improved catalysts and functional nanostructures.

• 出版日期2017-8