Department of Chemical and Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States.
Center for Nanophase Materials Science, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Nano Lett. 2017 Aug 9;17(8):4576-4582. doi: 10.1021/acs.nanolett.7b00827. Epub 2017 Jul 6.
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" FeO substrates by in situ microscopy. During in situ vacuum annealing of Au-FeO dumbbell-like nanoparticles, synthesized by the epitaxial growth of nano-FeO on Au nanoparticles, the gold nanoparticles transform into the gold thin films and wet the surface of nano-FeO, as the surface reduction of nano-FeO proceeds. This phenomenon results from a unique coupling of the size-and shape-dependent high surface reducibility of nano-FeO and the extremely strong adhesion between Au and the reduced FeO. 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.
金属-载体键合的强度决定了多相催化剂的热稳定性，因此，人们付出了巨大的努力来理解金属-载体相互作用。在此，我们通过原位显微镜报告了在金纳米粒子和“纳米工程化”FeO 基底之间发现的异常“强金属-载体键合”。在通过纳米-FeO 在 Au 纳米粒子上外延生长合成的 Au-FeO 哑铃状纳米粒子的原位真空退火过程中，随着纳米-FeO 的表面还原，金纳米粒子转变为金薄膜并润湿纳米-FeO 的表面。这种现象源于纳米-FeO 的高表面还原能力的尺寸和形状依赖性与 Au 和还原的 FeO 之间的极强附着力的独特结合。这种强金属-载体键合揭示了控制金属氧化物载体尺寸和形态对于优化金属-载体键合以及最终开发改进的催化剂和功能纳米结构的重要性。
