Modification of bifunctional Au-Ti catalysts for direct epoxidation of propylene with H₂ and O₂ is of burgeoning interest for potential commercialization requirements with desirable overall catalytic performance. Herein, we report a strategy by combining the addition of trace Pt into Au particles to enhance hydroperoxide species formation with the surface silylation to promote propylene oxide (PO) desorption. The resultant catalyst, that is, silylated Au₂₀Pt₁/uncalcined TS-1, gives rise to significantly enhanced propylene conversion of 11%, PO selectivity of 88%, and H₂ efficiency of 41%. The underlying nature of the above enhanced performance is elucidated by multiple techniques, such as high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectra, and theoretical calculations. The insights revealed here, the synergy of Au-Pt-Ti triple active sites together with the surface silylation, could guide the rational design of Au-Ti catalysts for propylene epoxidation to boost PO production.

中文翻译：

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将痕量 Pt 与表面硅烷化结合以促进 Au/未煅烧 TS-1 催化丙烯与 H2 和 O2 的环氧化

用于丙烯与 H ₂和 O ₂直接环氧化的双功能 Au-Ti 催化剂的改性对于具有理想的整体催化性能的潜在商业化要求具有新兴的兴趣。在此，我们报告了一种策略，将痕量 Pt 添加到 Au 颗粒中以增强氢过氧化物物质的形成，并通过表面硅烷化促进环氧丙烷 (PO) 解吸。所得催化剂，即甲硅烷基化的 Au ₂₀ Pt ₁ /未煅烧的 TS-1，使丙烯转化率显着提高 11%，PO 选择性为 88%，H ₂效率为 41%。上述增强性能的潜在本质通过多种技术阐明，例如高角度环形暗场扫描透射电子显微镜、X 射线光电子能谱、傅里叶变换红外光谱和理论计算。这里揭示的见解，Au-Pt-Ti 三重活性位点与表面硅烷化的协同作用，可以指导用于丙烯环氧化的 Au-Ti 催化剂的合理设计，以提高 PO 的产量。