针对碱催化缩合、酸催化脱水及金属催化加氢的多步串联反应中的协同催化问题，本项目拟以具有氮配位笼结构和明显电子传递特性、且酸碱性灵活可调的石墨型碳三氮四（g-C3N4）为主体，通过在笼内限域金属单原子等手段，构建类酶结构的负载型多功能催化剂M@g-C3N4，发展二维含氮碳材料内金属单原子的限域催化理论。研究g-C3N4缩聚程度、堆叠方式、孔结构及金属负载工艺对金属分散度的影响，获得金属在g-C3N4笼内单原子分散技术；研究限域环境下金属单原子与g-C3N4之间的主客体相互作用本质，掌握对M@g-C3N4催化剂宏观表现出来的酸、碱、加氢性的调控规律；研究M@g-C3N4催化的以丙酮加氢合成甲基异丁基酮（MIBK）为代表的多步串联反应过程，揭示催化机理和构效关系。本项目的开展，对于多功能催化剂的理论研究以及广泛存在的多步反应的集成强化等均具有重要意义。

Aiming at the problem of cooperative catalysis in the cascade reactions of condensation, dehydration, and hydrogenation catalyzed by base, acid and metal active sites, we developed a new enzyme-like multifunctional catalyst M@g-C3N4, which is composed of metal single atoms confined in the N-cooperative cages of g-C3N4, considering its cage structure, obvious electron transfer feature, and flexible adjustment of acidic and basic property. Furthermore, a catalytic theory on the metal single atoms confined in the two-dimensional N-containing carbon materials would be proposed. The effect of condensation degree, compacting style, pore structure of g-C3N4 and metal loading technogy on the dispersity of metal would be investigated to obtain the special dispersing technology of metal single atoms in the cages. In addition, the interaction of metal single atoms and g-C3N4 cages would be analyzed to adjust the acidic, basic and hydrogenation properties. Finally, the cascade reactions similar to the synthesis of MIBK from acetone catalyzed by M@g-C3N4 would be investigated, to reveal the catalytic mechanism and structure-performance relationship. This project would be significant to the theory study and the intensification of cascade reactions which ouured frequently in the chemical industry.