Yin Xianjun, Zhang Kefan, Xu Cui, Gao Qiang, Zhang Mengyang, Li Xu-Bing, Peng Hui-Qing, Tung Chen-Ho, Wu Li-Zhu, Liu Bin
State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Mater Science and Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100084, China.
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Angew Chem Int Ed Engl. 2025 Aug 4;64(32):e202508620. doi: 10.1002/anie.202508620. Epub 2025 Jun 10.
Achieving efficient and selective light-driven CO conversion to formic acid is a significant scientific challenge, particularly when utilizing purely organic, metal-free, and earth-abundant element-based molecule photocatalysts. Herein, we first reported the discovery of acridine derivatives (DADN, PXZN, and PTZN) as new-type, metal-free, self-sensitized molecule catalysts that enabled exceptional performance in solar-driven CO reduction to formic acid. Notably, the atomically engineered sulfur-containing heterocycle PTZN demonstrated unprecedented formate yield rate of 47.8 mmol g h and >99% selectivity in a photocatalytic system using 1,3-dimethyl-1H-benzo[d]imidazol-3-ium (BI) as proton and electron relay. The superior activity of PTZN was revealed to arise from its synergistic combination of strong CO-binding affinity (-0.195 eV), prolonged charge-separated states (11 ns), and robust CO electronic coupling (2.51 eV). Comprehensive studies including in situ electron spin resonance, in situ infrared, and transient absorption spectroscopy unambiguously unveiled a direct single electron transfer process from the excited singlet-state acridine derivatives to CO, generating CO . Moreover, a hydrogen atom transfer process utilizing in situ generated BIH as a hydrogen atom carrier enabled the conversion of CO to formic acid. This work establishes the first demonstration of a sequential proton-electron transfer mechanism in acridine-based photocatalysis, resolving long-standing challenges in proton and electron delivery during CO activation.
实现高效且选择性的光驱动CO转化为甲酸是一项重大的科学挑战，尤其是在使用纯有机、无金属且基于地壳丰富元素的分子光催化剂时。在此，我们首次报道发现吖啶衍生物（DADN、PXZN和PTZN）作为新型无金属自敏化分子催化剂，在太阳能驱动的CO还原为甲酸过程中表现出卓越性能。值得注意的是，经原子工程设计的含硫杂环PTZN在以1,3-二甲基-1H-苯并[d]咪唑-3-鎓（BI）作为质子和电子中继体的光催化体系中，展现出前所未有的甲酸盐产率47.8 mmol g h以及>99%的选择性。研究表明，PTZN的优异活性源于其强CO结合亲和力（-0.195 eV）、延长的电荷分离态（11 ns）和稳健的CO电子耦合（2.51 eV）的协同组合。包括原位电子自旋共振、原位红外和瞬态吸收光谱在内的综合研究明确揭示了从激发单重态吖啶衍生物到CO的直接单电子转移过程，生成CO 。此外，利用原位生成的BIH作为氢原子载体的氢原子转移过程实现了CO 向甲酸的转化。这项工作首次证明了基于吖啶的光催化中的顺序质子-电子转移机制，解决了CO活化过程中质子和电子传递方面长期存在的挑战。
