γ-Al2O3表面铝配位结构及催化含氧化合物脱水反应机理的高场原位固体核磁共振研究

γ-Al2O3既是目前最广泛使用的催化剂载体也是常用的生物质含氧化合物脱水催化剂，其表面铝的配位结构决定了其作为催化剂或负载催化剂的活性和稳定性。本项目针对传统γ-Al2O3表面因五配位铝含量少导致其表面铝的配位结构及催化机理认识不深入的问题，拟通过控制合成条件获得不同五配位铝含量的γ-Al2O3作为模型，利用高场多核、多维核磁共振技术结合红外光谱及DFT计算对γ-Al2O3表面铝的配位状态、含量、酸性及相应不同羟基结构之间的关系进行深入表征；通过对比不同方法制备的负载型催化剂，揭示其中客体原子与表面Al物种之间相互作用的本质；利用13C或选择性2H（氘）代乙醇为探针，结合原位固体核磁共振技术研究醇类等含氧分子脱水反应的中间物种和催化机理。这将为新型、高效γ-Al2O3及其负载催化剂的精准设计提供理论指导。

γ-Al2O3 is the most widely used catalyst support and also works as an important dehydration catalyst for oxygenates. The structure of surface Al species directly determines the activity and stability when it is used as catalyst or support. On the basis of lack of deep insight into the structure of surface Al species and related catalytical reaction mechanism due to very small amount of 5-coordinated Al present in commnonly used γ-Al2O3 , in this proposal, a series of γ-Al2O3 with various amount of 5-coordinated Al will be prepared as model materials. High-field multinuclear multidimensional solid-state NMR (ssNMR) combined with IR spectra and DFT calculations will be carried out to study the structure, amount, acidity and related hydroxide groups of the surface Al species. The interactions between the guest atoms and surface Al species will be elucidated through comparing the γ-Al2O3 supported catalysts prepared by different methods. The dehydration mechanism of oxygenates will be illustrated at molecular level via in situ ssNMR utilizing 13C or 2H enriched ethanol as model substrate. These studies will offer very valuable guidelines for precise design of novel high performance γ-Al2O3 based catalysts.