Scientific Center of Optical and Electron Microscopy (ScopeM), ETH Zürich, 8093 Zürich, Switzerland.
Institute for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland.
Science. 2022 May 27;376(6596):982-987. doi: 10.1126/science.abm3371. Epub 2022 May 26.
The dynamic interactions between noble metal particles and reducible metal-oxide supports can depend on redox reactions with ambient gases. Transmission electron microscopy revealed that the strong metal-support interaction (SMSI)-induced encapsulation of platinum particles on titania observed under reducing conditions is lost once the system is exposed to a redox-reactive environment containing oxygen and hydrogen at a total pressure of ~1 bar. Destabilization of the metal-oxide interface and redox-mediated reconstructions of titania lead to particle dynamics and directed particle migration that depend on nanoparticle orientation. A static encapsulated SMSI state was reestablished when switching back to purely oxidizing conditions. This work highlights the difference between reactive and nonreactive states and demonstrates that manifestations of the metal-support interaction strongly depend on the chemical environment.
贵金属颗粒与可还原金属氧化物载体之间的动态相互作用可能取决于与环境气体的氧化还原反应。透射电子显微镜显示，在还原条件下观察到的铂颗粒在二氧化钛上的强金属-载体相互作用（SMSI）诱导包裹作用，一旦系统暴露于含有氧气和氢气的氧化还原反应环境中，总压力约为 1 巴，这种包裹作用就会消失。金属-氧化物界面的不稳定性和氧化还原介导的二氧化钛重构导致了依赖于纳米颗粒取向的颗粒动力学和定向颗粒迁移。当切换回纯氧化条件时，重新建立了静态的封装 SMSI 状态。这项工作强调了反应性和非反应性状态之间的差异，并表明金属-载体相互作用的表现强烈依赖于化学环境。
