Ishikawa Ryo, Ueno Yujiro, Ikuhara Yuichi, Shibata Naoya
Institute of Engineering Innovation, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan.
PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
Nano Lett. 2022 May 25;22(10):4161-4167. doi: 10.1021/acs.nanolett.2c00929. Epub 2022 May 9.
The catalytic activity and selectivity of heterogeneous catalysts are governed by atomic and electronic structures at the heterointerface between noble metal nanoparticles (NPs) and oxide substrates. In specific chemical reactions, it is well-known that the catalytic activity is strongly suppressed by annealing in a reducing atmosphere, so-called strong metal-support interaction (SMSI). However, it is still unclear the formation process and atomistic origin of the SMSI. By preparing well-defined platinum (Pt) NPs supported on atomically flat TiO (110) substrate, we directly show the formation of chemically ordered Pt-Ti intermetallic NPs and impregnation of NPs into TiO substrate at high temperatures by using atomic-resolution scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Furthermore, we observed negative charge transfer from the Pt-Ti intermetallic NPs to the TiO surface, which would strongly affect the catalytic activities.
多相催化剂的催化活性和选择性由贵金属纳米颗粒（NPs）与氧化物载体之间的异质界面处的原子和电子结构决定。在特定化学反应中，众所周知，在还原气氛中退火会强烈抑制催化活性，即所谓的强金属-载体相互作用（SMSI）。然而，SMSI的形成过程和原子起源仍不清楚。通过制备负载在原子级平整的TiO（110）衬底上的明确铂（Pt）NPs，我们使用原子分辨率扫描透射电子显微镜结合电子能量损失谱，直接展示了高温下化学有序的Pt-Ti金属间化合物NPs的形成以及NPs向TiO衬底中的浸渍。此外，我们观察到从Pt-Ti金属间化合物NPs到TiO表面的负电荷转移，这将强烈影响催化活性。
