Zhang Li, Huang Yike, Wang Yuehan, Wang Zhen, Huang Chuande, Yang Xiaofeng, Qiao Botao, Wang Xiaodong, Zhang Tao
CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Artificial Intelligence for Science Institute, Beijing 100080, China.
J Am Chem Soc. 2025 Aug 13;147(32):29496-29504. doi: 10.1021/jacs.5c10016. Epub 2025 Jul 31.
Direct methane conversion (DMC) to oxygenates with high reactivity and selectivity represents one of the greatest challenges in catalysis. Herein, we report an enzyme-mimicking Cu single-atom catalyst for efficient DMC using HO and O as the oxidant. Upon oxidation with HO, Cu single atoms are stabilized in the form of N-Cu-O at the zigzag edge of carbon nitride, endowing highly covalent Cu-O pair for homolytic C-H cleavage of methane (diameter of 3.78 Å) with a low barrier of 0.58 eV. Importantly, the formed methyl radicals could be captured by O and generate CHOOH (diameter >4.2 Å) as the primary product, whose back diffusion and overoxidation over Cu are retarded via the steric hindrance of the zigzag edge that holds a "V-type" configuration with an entrance width of 3.87 Å. Such synergy between active centers and the specific steric hindrance of the surrounding geometric structure, analogous to the gating mechanism of methane monooxygenase, gives a high turnover frequency of 405.3 ± 8.2 h with ∼100% selectivity at 50 °C.
将甲烷直接转化（DMC）为具有高反应活性和选择性的含氧化合物是催化领域最具挑战性的课题之一。在此，我们报道了一种模仿酶的铜单原子催化剂，用于以HO和O作为氧化剂的高效DMC反应。在用HO氧化时，铜单原子以N-Cu-O的形式稳定在氮化碳的锯齿边缘，形成高度共价的Cu-O对，用于甲烷（直径3.78 Å）的均裂C-H键断裂，其低势垒为0.58 eV。重要的是，形成的甲基自由基可被O捕获，并生成CHOOH（直径>4.2 Å）作为主要产物，通过具有“V型”构型且入口宽度为3.87 Å的锯齿边缘的空间位阻，抑制了其在铜上的反向扩散和过度氧化。活性中心与周围几何结构的特定空间位阻之间的这种协同作用，类似于甲烷单加氧酶的门控机制，在50 °C下具有405.3 ± 8.2 h的高周转频率和约100%的选择性。
