An Iron Bis(carbene) Catalyst for Low Overpotential CO 2 Electroreduction to CO: Mechanistic Insights from Kinetic Zone Diagrams, Spectroscopy, and Theory
An Iron Bis(carbene) Catalyst for Low Overpotential CO 2 Electroreduction to CO: Mechanistic Insights from Kinetic Zone Diagrams, Spectroscopy, and Theory
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用于低过电势 CO 2 电还原为 CO 的铁双卡宾催化剂：来自动力学区带图、光谱学和理论的机理见解
DOI：
10.1021/acscatal.1c04414
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发表时间：
2021
期刊：
影响因子：
12.9
通讯作者：
Miller, Alexander J.
中科院分区：
文献类型：
--
作者：
Gonell, Sergio;Assaf, Eric A.;Lloret-Fillol, Julio;Miller, Alexander J.
分子电催化中的一个常见挑战是最大活性与达到该速率所需的过电位之间的关系，其中较快的催化剂会产生较高的过电位。这项工作遵循一种基于独立调整初级配位体的策略，以发现一种以前未报道的用于CO2还原的铁催化剂，其活性高于类似络合物，同时保持相同的超电势。合成了一种含双氮杂环卡宾（亚甲基双（N-甲基咪唑-2-亚基），bis-mim）和一个氧化还原活性的2，2 ′：6′，2 ″-三联吡啶（tpy）的铁配合物，并发现其在低过电位下以水为质子源催化CO2选择性还原为CO.基于动力学区域图，光谱学和计算的机制研究，使以前研究的吡啶基卡宾类似物的比较。改变双齿配体给体的能力，加速催化在相同的过电位和改变的性质的周转限制步骤的反应。
A common challenge in molecular electrocatalysis is the relationship between maximum activity and the overpotential required to reach that rate, with faster catalysts incurring higher overpotentials. This work follows a strategy based on independent tuning of ligands in the primary coordination sphere to discover a previously unreported iron catalyst for CO2reduction with higher activity than similar complexes while maintaining the same overpotential. Iron complexes bearing a bis-N-heterocyclic carbene ligand (methylenebis(N-methylimidazol-2-ylidene), bis-mim) and a redox active 2,2′:6′,2″-terpyridine (tpy) ligand were synthesized and found to catalyze the selective reduction of CO2to CO at low overpotential with water as the proton source. Mechanistic studies based on kinetic zone diagrams, spectroscopy, and computation enable comparisons with a previously studied pyridyl–carbene analogue. Changing the bidentate ligand donor ability accelerates catalysis at the same overpotential and changes the nature of the turnover-limiting step of the reaction.