Asymmetric coordination effect is an important concept in heterogeneous catalysis where both catalytic activity and product selectivity are serious influenced. However, this effect has rarely been understood because of the difficult in characterizing detailed coordination information. Here, by employing a theoretical study on electrocatalytic CO2 reduction reaction (ECO2RR) towards HCOOH over Ti3C2O2-based NS/NN co-coordinated transition metal single atom catalysts (TM-NS/NN-Ti3C2O2 SACs), we show that asymmetric coordination environments have great impact on the electronic structure of the active center. Both electron transferring ability and spin polarization of the active center are vital to optimize the adsorption and hydrogenation of key intermediates. As a result, both catalytic activity and product selectivity can be maximized. V-NN-Ti3C2O2 are predicted to promote high-throughput HCOOH generation process at operation applied potential of −0.32 with considerable electrochemical stability, surpassing most reported catalysts. This work demonstrates V-NN-Ti3C2O2 as high-performance ECO2RR catalysts, and highlights that the introduction of the concept of asymmetric coordination effect may offer a new insight into the rational design of more efficient SACs.

中文翻译：

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基于 MXene 的单原子催化剂中活性中心的不对称配位工程，用于高性能 ECO2RR


不对称配位效应是多相催化中的一个重要概念，其中催化活性和产物选择性都受到严重影响。然而，由于难以描述详细的配位信息，这种效应很少被理解。在这里，通过对基于 Ti3C2O2 的 NS/NN 共配位过渡金属单原子催化剂 （TM-NS/NN-Ti3C2O2 SAC） 上电催化 CO2 还原反应 （ECO2RR） 对 HCOOH 的理论研究，我们表明不对称配位环境对活性中心的电子结构有很大影响。活性中心的电子转移能力和自旋极化对于优化关键中间体的吸附和氢化都至关重要。因此，催化活性和产物选择性都可以最大化。预计 V-NN-Ti3C2O2 将在 -0.32 的操作应用电位下促进高通量 HCOOH 生成过程，具有相当大的电化学稳定性，超过了大多数已报道的催化剂。这项工作证明了 V-NN-Ti3C2O2 作为高性能 ECO2RR 催化剂，并强调不对称配位效应概念的引入可能为更高效 SAC 的合理设计提供新的见解。