| 何念秋,郑燕萍,陈明树.Al2O3负载Pt基催化剂表面动态变化的谱学研究[J].分子催化,2024,38(1):7-16 |
| Al2O3负载Pt基催化剂表面动态变化的谱学研究 |
| Spectroscopic Study of Surface Dynamics of Al2O3 Supported Pt-Catalysts |
| 投稿时间：2023-09-21 修订日期：2023-10-16 |
| DOI：10.16084/j.issn1001-3555.2024.01.002 |
| 中文关键词: 表面动态过程 原位表征 丙烷脱氢 Pt基催化剂 单原子催化剂 |
| 英文关键词:surface dynamics in-situ characterization propane dehydrogenation Pt-based catalyst single-atom site catalyst |
| 基金项目:国家重点研发计划(2020YFB0606401, 2021YFA1502801)和国家自然科学基金(22132004, 12241502)(National Key Research and Development Program of China(2020YFB0606401, 2021YFA1502801) and National Natural Science Foundation of China (22132004, 12241502)). |
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| 中文摘要: |
| 明确多相催化剂表面在反应过程的动态变化对催化剂的优化、设计有重要意义. 我们通过控制Pt的不同负载量制备了一系列Al2O3负载的Pt/Al2O3催化剂, 利用X-射线衍射、X-光电子能谱、球差扫描电镜、CO-探针的红外光谱、低能离子散射谱、程序升温氧化和拉曼光谱等研究Pt/Al2O3的表面结构和反应过程中的变化, 以丙烷直接脱氢(PDH)反应为探针, 考察反应过程存在“诱导”期的表面动态变化, 特别是表面积碳、表面形貌、活性位点等的演化. 进而与其催化反应性能关联, 发现Pt纳米粒子(NP)和团簇上丙烷易深度脱氢或断裂C—C键生成CH4的同时形成积碳、随后失去活性; 而孤立的Pt单原子位点(SAC)上不易生成积碳、是丙烯生成的关键活性位. |
| 英文摘要: |
| Understanding the dynamic changes of heterogeneous catalyst under reaction conditions is very important for improving the catalyst and designing a new catalyst. In present study, a series of Al2O3 supported Pt/Al2O3 catalysts were prepared with various Pt loadings. Surface structures and changes were studied by the X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), CO probed Fourier transform infrared spectroscopy (CO-FTIR), low energy ion scattering spectroscopy (LEIS), temperature programmed oxidation of carbon (TPOC) and Raman spectroscopy. Propane dehydrogenation (PDH) was used as a probe reaction. Surface dynamics, especially coke formation, surface morphology and active sites were investigated, and correlated with catalytic performance. It was found that Pt/Al2O3 catalysts underwent an ‘induction’ period for PDH. Propane was easy to deeply dehydrogenate, broke C—C bond on Pt nanoparticles (NP) and clusters to form CH4 and coke, resulted in a lower activity. In contrast, the isolated Pt single-atom central sites (SAC) were not easy to form coke, and would mainly be the active sites for propylene formation. |
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