Manipulating Gold Spatial Location on Titanium Silicalite-1 To Enhance the Catalytic Performance for Direct Propene Epoxidation with H2 and O2,ACS Catalysis

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Manipulating Gold Spatial Location on Titanium Silicalite-1 To Enhance the Catalytic Performance for Direct Propene Epoxidation with H2 and O2
ACS Catalysis ( IF 11.3 ) Pub Date : 2018-10-02 00:00:00 , DOI: 10.1021/acscatal.8b02836
Xiang Feng _{1,

2} , Zhaoning Song ₁ , Yibin Liu ₁ , Xiaobo Chen ₁ , Xin Jin ₁ , Wenjuan Yan ₁ , Chaohe Yang ₁ , Jun Luo ₃ , Xinggui Zhou ₄ , De Chen ₂

Affiliation

Engineering Au spatial locations on support harbors tremendous potential to boost catalytic performance but still remains a scientific and technological challenge. Herein, we devise a strategy to manipulate Au spatial location inside micropores of TS-1 support by tuning Au hydrolysis process. By multitechniques (e.g., quench molecular dynamics simulations, aberration-corrected HAADF-STEM, in situ UV–vis, and quantitative model calculation), the correlation between Au dynamic location and average x in [AuCl_x(OH)_4-x]⁻ complexes is established. It is found that compositions and locations of Au complexes can be effectively manipulated using different preparation temperature. This results in more effective Au clusters in TS-1 microporous channels and smaller-sized Au NPs on external surfaces. Gratifyingly, the optimum Au/TS-1 catalyst shows the reported highest initial PO formation rate without adding promoters and high stable activity for direct propene epoxidation with H₂ and O₂. Moreover, single Au atoms and Au clusters on Au/TS-1 catalyst are directly observed for the first time. However, overmuch Au clusters inside TS-1 only result in diffusion limit and poor performance, indicating that “effectively accommodated Au clusters” play a pivotal role. This strategy together with mechanistic results should allow significant progress in the design of efficient Au catalysts in the near future.

中文翻译：

操纵Silicalite-1钛上的金空间位置以增强H ₂和O ₂直接丙烯环氧化的催化性能

在支架上设计Au的空间位置具有提高催化性能的巨大潜力，但仍然是科学和技术挑战。本文中，我们设计了一种通过调节Au水解过程来控制TS-1载体微孔内部Au空间定位的策略。通过多种技术（例如，淬灭分子动力学模拟，像差校正的HAADF-STEM，原位UV-vis和定量模型计算），Au动态位置与[AuCl _x（OH）_4-_x ]中平均值x之间的相关性^-复合体成立。发现使用不同的制备温度可以有效地操纵Au络合物的组成和位置。这会在TS-1微孔通道中产生更有效的金簇，并在外表面上产生较小尺寸的金纳米颗粒。令人欣慰的是，最佳的Au / TS-1催化剂显示出报道的最高初始PO生成速率，而无需添加促进剂，并且对H ₂和O _2的直接丙烯环氧化具有很高的稳定性。此外，首次直接观察到Au / TS-1催化剂上的单个Au原子和Au团簇。然而，TS-1内部过多的金簇只会导致扩散极限和较差的性能，这表明“有效容纳的金簇”起着举足轻重的作用。这种策略以及机械结果将在不久的将来使高效Au催化剂的设计取得重大进展。

更新日期：2018-10-02

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