【摘要】 以高温氨气处理制得含氮微孔钛硅分子筛(NTS-1)为载体,用沉积-沉淀法制得了一系列纳米金催化剂.考察了纳米金催化剂在氢气和氧气共存下催化丙烯气相环氧化制环氧丙烷反应中的催化性能.结果表明,高温氨气处理钛硅分子筛(TS-1)载体降低了其酸性,提高了纳米金催化剂制备中金的利用率和纳米金催化剂中金的分散度,显著提高纳米金催化剂的催化活性.载体酸性降低和载体表面–NH2配位效应增强了催化剂活性.更多还原

【Abstract】 Nitrogen-incorporated titanium silicalite-1 (NTS-1) was used to prepare a supported goldcatalyst for direct gas-phase epoxidation of propylene using H2 and O2. The NTS-1 was synthesized by direct calcination ofthe TS-1 powder in a flow of NH3 at high temperature. Gold catalyst supported on NTS-1 was synthesized by the deposition-precipitationmethod. The samples were characterized by X-ray diffraction, N2 adsorption-desorption,diffuse reflectance ultraviolet-visiblespectroscopy, inductively coupled plasma optical emission spectrometry, elemental analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results indicated thatnitrogen was incorporated into the TS-1 framework, and that the NTS-1 preserved the multidimensional fatigue inventory (MFI) structure well. It was found thatNH3-treatment resulted in decreased acidity of the TS-1 zeolite support and improvedboth the Au capture efficiency and dispersion, which remarkably improved the catalytic performance.The enhanced activity was ascribed to the decrease inacidic surface sites and the ligand effect of the terminal NH2 groups on the support surface.更多还原