Authors: Hong Liu, Haiyuan Zou, Mei Wang, Hongliang Dong, Dan Wang, Fan Li, Hao Dai, Tao Song, Shuting Wei, Yongfei Ji, Chenguang Wang, Lele Duan
Published: 2022-09-26
Source: Full article
AbstractAccurate control over the coordination circumstances of single‐atom catalysts (SACs) is decisive to their intrinsic activity. Here, two single‐site heterogeneous organometallic catalysts (SHOCs), Cp*Ir‒L/GDY (L = OH− and Cl−; Cp* = pentamethylcyclopentadienyl), with the fine‐tuned local coordination and electronic structure of Ir sites, are constructed by anchoring Cp*Ir complexes on graphdiyne (GDY) matrix via a one‐pot procedure. The spectroscopic studies and theoretical calculations indicate that the Ir atoms in Cp*Ir‒Cl/GDY and Cp*Ir‒OH/GDY have a much higher oxidation state than Ir in the SAC Ir/GDY. As a proof‐of‐principle demonstration, the GDY‐supported SHOCs are used for formic acid dehydrogenation, which display a fivefold enhancement of catalytic activity compared with SAC Ir/GDY. The kinetic isotope effect and in situ Fourier‐transform infrared studies reveal that the rate‐limiting step is the β‐hydride elimination process, and Cp* on the Ir site accelerates the β‐hydride elimination reaction. The GDY‐supported SHOCs integrate the merits of both SACs and molecular catalysts, wherein the isolated Ir anchored on GDY echoes with SACs’ behavior, and the Cp* ligand enables precise structural and electronic regulation like molecular catalysts. The scheme of SHOCs adds a degree of freedom in accurate regulation of the local structure, the electronic property, and therefore the catalytic performance of single‐atom catalysts.