铜基催化剂在甲烷直接氧化制甲醇反应中活性位点的结构研究

甲烷直接氧化制备各种化学品是提高天然气利用效率的直接和有效途径。铜(Cu)/分子筛催化剂因能够在较低温度下催化甲烷选择性氧化到甲醇而成为研究热点。尽管多种光谱学和计算方法被用于研究Cu/分子筛催化剂，但对于其催化活性位点的确切状态仍然存在很多争议。本项目拟使用我们团队新开发的低剂量高分辨（扫描）透射电子显微镜技术对Cu/分子筛催化剂（以及相关的Cu/氧化物催化剂）的活性位点的结构和位置进行精确表征。利用这一技术，我们能够在原子分辨率尺度直接观察催化剂中Cu物种的存在形式，并同时使用电子能量损失谱确定其化学环境和价态。结合催化剂在甲烷直接氧化制甲醇反应中的催化性能，我们可以构建催化活性位点与反应性能之间的构效关系，更加深入地理解Cu基活性结构的催化作用机制。

Direct oxidation of methane to produce various chemicals is a direct and effective way to improve the efficiency of natural gas utilization. Copper (Cu)/zeolite catalysts have attracted great research attention, due to their unique ability to catalyze the selective oxidation of methane to methanol at lower temperatures. Although a variety of spectroscopies and calculation methods have been used to study Cu/zeolite catalysts, there are still disputes and controversies about the exact state of their catalytic active sites. In this proposed project, we will use our newly developed low-dose high-resolution (scanning) transmission electron microscopy technique to precisely characterize the structure and position of the active site in Cu/zeolite catalysts (and related Cu/oxide catalysts). This technique will allow us to directly observe the Cu species in the catalyst with atomic resolution and determine their chemical environments and valence states through electron energy loss spectroscopy. The ultimate goal of this project is to construct the structure-activity relationship for Cu-based catalysts, and gain more new insights into the catalytic mechanism of Cu species in the reaction of direct oxidation of methane to methanol.