Guo Ying, Shi Wenjie, Yang Huijuan, He Quanfeng, Zeng Zhongming, Ye Jin-Yu, He Xinru, Huang Ruiyun, Wang Cheng, Lin Wenbin
State Key Laboratory of Physical Chemistry of Solid Surfaces, iCHEM, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , P.R. China.
Department of Chemistry , The University of Chicago , 929 East 57th Street , Chicago , Illinois 60637 , United States.
J Am Chem Soc. 2019 Nov 6;141(44):17875-17883. doi: 10.1021/jacs.9b09227. Epub 2019 Oct 25.
Pyridinium has been shown to be a cocatalyst for the electrochemical reduction of CO on metal and semiconductor electrodes, but its exact role has been difficult to elucidate. In this work, we create cooperative cobalt-protoporphyrin (CoPP) and pyridine/pyridinium (py/pyH) catalytic sites on metal-organic layers (MOLs) for an electrocatalytic CO reduction reaction (CORR). Constructed from [Hf(μ-O)(μ-OH)(HCO)] secondary building units (SBUs) and terpyridine-based tricarboxylate ligands, the MOL was postsynthetically functionalized with CoPP via carboxylate exchange with formate capping groups. The CoPP group and the pyridinium (pyH) moiety on the MOL coactivate CO by forming the [pyH-OC-CoPP] adduct, which enhances the CORR and suppresses hydrogen evolution to afford a high CO/H selectivity of 11.8. Cooperative stabilization of the [pyH-OC-CoPP] intermediate led to a catalytic current density of 1314 mA/mgCo for CO production at -0.86 V, which corresponds to a turnover frequency of 0.4 s.
吡啶鎓已被证明是金属和半导体电极上电化学还原CO的助催化剂，但其确切作用一直难以阐明。在这项工作中，我们在金属有机层（MOL）上创建了协同的钴原卟啉（CoPP）和吡啶/吡啶鎓（py/pyH）催化位点，用于电催化CO还原反应（CORR）。该MOL由[Hf(μ-O)(μ-OH)(HCO)]二级结构单元（SBUs）和基于三联吡啶的三羧酸配体构建而成，通过与甲酸封端基团进行羧酸盐交换，在合成后用CoPP对MOL进行功能化。MOL上的CoPP基团和吡啶鎓（pyH）部分通过形成[pyH-OC-CoPP]加合物来共同激活CO，这增强了CORR并抑制析氢，从而提供了11.8的高CO/H选择性。[pyH-OC-CoPP]中间体的协同稳定导致在-0.86 V下产生CO的催化电流密度为1314 mA/mgCo，这对应于0.4 s的周转频率。
