Liu Hai-Xiong, Zhou Zi-Jian, Xie Lei, Liu Chen, Cai Lei, Wu Xin-Ping, Liu Tian-Fu
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, No.8, Gaoxindadao Road, Shangjie, Minhou, Fuzhou, 350108, P.R. China.
State Key Laboratory of Green Chemical Engineering and Industrial Catalysis, Key Laboratory for Advanced Materials and Joint International Research Laboratory for Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Centre for Computational Chemistry and Research Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P.R. China.
Angew Chem Int Ed Engl. 2024 Nov 18;63(47):e202411508. doi: 10.1002/anie.202411508. Epub 2024 Oct 10.
The conversion of CO to C through photocatalysis poses significant challenges, and one of the biggest hurdles stems from the sluggishness of the multi-electron transfer process. Herein, taking metal-organic framework (MOF, PFC-98) as a model photocatalyst, we report a new strategy to facilitate charge separation. This strategy involves matching the energy levels of the lowest unoccupied node and linker orbitals of the MOF, thereby creating the lowest unoccupied crystal orbital (LUCO) delocalized over both the node and linker. This feature enables the direct excitation of electrons from photosensitive linker to the catalytic centers, achieving a direct charge transfer (DCT) pathway. For comparison, an isoreticular MOF (PFC-6) based on analogue components but with far apart frontier energy level was synthesized. The delocalized LUCO caused the presence of an internal charge-separated (ICS) state, prolonging the excited state lifetime and further inhibiting the electron-hole recombination. The presence of ICS state prolongs the excited state lifetime and further inhibits the electron-hole recombination. Moreover, it also induced abundant electrons accumulating at the catalytic sites, enabling the multi-electron transfer process. As a result, the material featuring delocalized LUCO exhibits superior overall CO photocatalytic performance with high C production yield and selectivity.
通过光催化将CO转化为C面临着重大挑战，其中最大的障碍之一源于多电子转移过程的迟缓。在此，以金属有机框架（MOF，PFC-98）作为模型光催化剂，我们报告了一种促进电荷分离的新策略。该策略涉及匹配MOF的最低未占据节点和连接体轨道的能级，从而创建在节点和连接体上均离域的最低未占据晶体轨道（LUCO）。这一特性使得电子能够从光敏连接体直接激发到催化中心，实现直接电荷转移（DCT）途径。为了进行比较，合成了一种基于类似组分但前沿能级相距甚远的同构MOF（PFC-6）。离域的LUCO导致了内禀电荷分离（ICS）态的存在，延长了激发态寿命并进一步抑制了电子-空穴复合。ICS态的存在延长了激发态寿命并进一步抑制了电子-空穴复合。此外，它还诱导大量电子在催化位点积累，从而实现多电子转移过程。结果，具有离域LUCO的材料表现出优异的整体CO光催化性能，具有高的C产率和选择性。
