Enhancing the inherent catalytic activity and stability of TiO2 supported Pt single-atoms at CeOx–TiO2 interfaces,Journal of Materials Chemistry A

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Enhancing the inherent catalytic activity and stability of TiO2 supported Pt single-atoms at CeOx–TiO2 interfaces
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2021-10-12 , DOI: 10.1039/d1ta08059h
Mi Yoo ₁ , Eunji Kang ₁ , Hyuk Choi ₁ , Hyunwoo Ha ₁ , Hanseul Choi _{2,

3} , Jin-Seok Choi ₄ , Kug-Seung Lee ₅ , Richard Celestre ₆ , David A. Shapiro ₆ , Jeong Young Park _{2,

3} , Chunjoong Kim ₁ , Young-Sang Yu _{6,

7} , Hyun You Kim ₁

Affiliation

Single-atoms (SAs) with atomically coordinated reaction centers are considered the next generation of catalysts that can exhibit exceptional catalytic efficiency. However, the general concern about thermodynamic vulnerabilities of SAs questions their practical value. Moreover, whether the inherent catalytic nature of SAs is superior compared with that of larger nanoparticles is still under debate. Here, we address two controversies by a comparative study using two catalysts: Pt/TiO₂ and Pt/CeO_x–TiO₂. Based on a hierarchical study of density functional theory, time-resolved catalysis performance test, in situ infrared spectroscopy, and operando X-ray absorption spectroscopy, we could unveil the catalytic nature of Pt-SAs and their stability. By utilizing the heterogeneous interface formed between TiO₂ supporting particles and CeO_x clusters formed on the surface of TiO₂, we preferentially synthesized Pt-SAs pinned at the CeO_x–TiO₂ interfaces on CeO_x–TiO₂ hybrid-oxide supports. The strong electronic coupling between the Pt-SAs and the Ce ions at the CeO_x–TiO₂ interfaces enhanced the catalytic activity toward CO oxidation of Pt-SAs and improved the long-term stability under CO oxidation conditions. The CO oxidation activity of Pt-SAs stabilized at CeO_x–TiO₂ was improved by 13.5 times at 200 °C compared with the Pt-SAs on TiO₂. The results present how to easily improve the activity and stability of Pt-SAs using a simple interface control method. Moreover, we demonstrate that the catalytic activity and the stability of Pt-SAs can be monitored through the chemical state of the interfaces. Our study provides comprehensive understanding about the catalytic nature as well as a novel strategy toward applications of Pt-SAs, enabling sustainable use of Pt in heterogeneous catalysts.

中文翻译：

提高在 CeOx-TiO2 界面上 TiO2 负载的 Pt 单原子的固有催化活性和稳定性

具有原子配位反应中心的单原子 (SA) 被认为是具有卓越催化效率的下一代催化剂。然而，人们普遍关注 SA 的热力学脆弱性，质疑它们的实用价值。此外，与较大的纳米粒子相比，SAs 的固有催化性质是否更优越仍存在争议。在这里，我们通过使用两种催化剂的比较研究来解决两个争议：Pt/TiO ₂和 Pt/CeO _x –TiO ₂。基于密度泛函理论、时间分辨催化性能测试、原位红外光谱和操作数的分层研究通过 X 射线吸收光谱，我们可以揭示 Pt-SAs 的催化性质及其稳定性。通过利用TiO ₂负载颗粒和TiO ₂表面形成的CeO _x簇之间形成的异质界面，我们优先合成了固定在CeO _x -TiO ₂混合氧化物载体上的CeO _x -TiO ₂界面上的Pt-SAs 。Pt-SAs 和 CeO _x –TiO ₂处的 Ce 离子之间的强电子耦合界面增强了对 Pt-SAs 的 CO 氧化的催化活性，并提高了 CO 氧化条件下的长期稳定性。与 TiO ₂上的 Pt-SAs 相比，在 200 °C 下稳定在 CeO _x -TiO _{2 上}的 Pt-SAs 的 CO 氧化活性提高了 13.5 倍。结果展示了如何使用简单的界面控制方法轻松提高 Pt-SAs 的活性和稳定性。此外，我们证明了可以通过界面的化学状态监测 Pt-SAs 的催化活性和稳定性。我们的研究提供了对催化性质的全面理解以及 Pt-SA 应用的新策略，使 Pt 在多相催化剂中的可持续使用成为可能。

更新日期：2021-10-27

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