Abdel-Mageed Ali M, Rungtaweevoranit Bunyarat, Impeng Sarawoot, Bansmann Joachim, Rabeah Jabor, Chen Shilong, Häring Thomas, Namuangrak Supawadee, Faungnawakij Kajornsak, Brückner Angelika, Behm R Jürgen
Inst. of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, 89081, Ulm, Germany.
Leibniz Institute for Catalysis (LIKAT Rostock), 18059, Rostock, Germany.
Angew Chem Int Ed Engl. 2023 Jul 24;62(30):e202301920. doi: 10.1002/anie.202301920. Epub 2023 Jun 14.
Elucidating the reaction mechanism in heterogeneous catalysis is critically important for catalyst development, yet remains challenging because of the often unclear nature of the active sites. Using a molecularly defined copper single-atom catalyst supported by a UiO-66 metal-organic framework (Cu/UiO-66) allows a detailed mechanistic elucidation of the CO oxidation reaction. Based on a combination of in situ/operando spectroscopies, kinetic measurements including kinetic isotope effects, and density-functional-theory-based calculations, we identified the active site, reaction intermediates, and transition states of the dominant reaction cycle as well as the changes in oxidation/spin state during reaction. The reaction involves the continuous reactive dissociation of adsorbed O , by reaction of O with CO , leading to the formation of an O atom connecting the Cu center with a neighboring Zr ion as the rate limiting step. This is removed in a second activated step.
阐明多相催化中的反应机理对于催化剂开发至关重要，但由于活性位点的性质往往不明确，这仍然具有挑战性。使用由UiO-66金属有机框架负载的分子定义的铜单原子催化剂（Cu/UiO-66），可以对CO氧化反应进行详细的机理阐释。基于原位/操作光谱学、包括动力学同位素效应的动力学测量以及基于密度泛函理论的计算相结合，我们确定了主导反应循环的活性位点、反应中间体和过渡态，以及反应过程中氧化/自旋状态的变化。该反应涉及吸附的O通过O与CO的反应进行连续的反应解离，导致形成一个将Cu中心与相邻Zr离子连接的O原子作为速率限制步骤。这在第二个活化步骤中被去除。
