Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Inorg Chem. 2020 Jul 6;59(13):9270-9278. doi: 10.1021/acs.inorgchem.0c01162. Epub 2020 Jun 17.
We present a bioinspired strategy for enhancing electrochemical carbon dioxide reduction catalysis by cooperative use of base-metal molecular catalysts with intermolecular second-sphere redox mediators that facilitate both electron and proton transfer. Functional synthetic mimics of the biological redox cofactor NADH, which are electrochemically stable and are capable of mediating both electron and proton transfer, can enhance the activity of an iron porphyrin catalyst for electrochemical reduction of CO to CO, achieving a 13-fold rate improvement without altering the intrinsic high selectivity of this catalyst platform for CO versus proton reduction. Evaluation of a systematic series of NADH analogues and redox-inactive control additives with varying proton and electron reservoir properties reveals that both electron and proton transfer contribute to the observed catalytic enhancements. This work establishes that second-sphere dual control of electron and proton inventories is a viable design strategy for developing more effective electrocatalysts for CO reduction, providing a starting point for broader applications of this approach to other multielectron, multiproton transformations.
我们提出了一种仿生策略，通过协同使用具有分子间第二壳层氧化还原介体的基础金属分子催化剂来增强电化学二氧化碳还原催化作用，这有利于电子和质子转移。NADH 的功能合成模拟物是电化学稳定的，并且能够介导电子和质子转移，可提高铁卟啉催化剂对 CO 电化学还原为 CO 的活性，在不改变该催化剂平台对 CO 与质子还原的固有高选择性的情况下，将反应速率提高了 13 倍。对具有不同质子和电子储存库性质的一系列 NADH 类似物和氧化还原非活性控制添加剂进行评估，结果表明电子和质子转移都有助于观察到的催化增强。这项工作确立了第二壳层对电子和质子库存的双重控制是开发更有效的 CO 还原电催化剂的可行设计策略，为将这种方法更广泛地应用于其他多电子、多质子转化提供了起点。
