Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
J Am Chem Soc. 2022 Feb 23;144(7):2829-2840. doi: 10.1021/jacs.1c11500. Epub 2022 Feb 9.
To achieve high selectivity in enzyme catalysis, nature carefully controls both the catalyst active site and the pocket or environment that mediates access and the geometry of a reactant. Despite the many advantages of heterogeneous catalysis, active sites on a surface are rarely defined with atomic precision, making it difficult to control reaction selectivity with the molecular precision of homogeneous systems. In colloidal nanoparticle synthesis, structural control is accomplished using a surface ligand or capping layer that stabilizes a specific particle morphology and prevents nanoparticle aggregation. Usually, these surface ligands are considered detrimental for catalysis because they occupy otherwise active surface sites. However, a number of examples have shown that surface ligands can play a beneficial role in defining the catalytic environment and enhancing performance by a variety of mechanisms. This perspective summarizes recent advances and opportunities using surface ligands to enhance the performance of nanocatalysts for electrochemical CO reduction. Several mechanisms are discussed, including selective permeability, modulating interfacial solvation structure and electric fields, chemical activation, and templating active site selection. These examples inform strategies and point to emerging opportunities to design nanocatalysts toward molecular level control of electrochemical CO conversion.
为了在酶催化中实现高选择性，自然界精心控制催化剂的活性位点和口袋或环境，以调节反应物的进入和几何形状。尽管多相催化有许多优点，但表面上的活性位点很少能达到原子精度，因此很难像均相体系那样以分子精度控制反应选择性。在胶体纳米粒子合成中，结构控制是通过使用表面配体或封端层来实现的，表面配体可以稳定特定的粒子形态并防止纳米粒子聚集。通常情况下，这些表面配体被认为对催化有害，因为它们占据了原本活跃的表面位点。然而，许多例子表明，表面配体可以通过多种机制在定义催化环境和提高性能方面发挥有益的作用。本观点总结了利用表面配体来提高纳米催化剂电化学 CO 还原性能的最新进展和机遇。讨论了几种机制，包括选择性渗透性、调节界面溶剂化结构和电场、化学活化和模板化活性位点选择。这些例子为设计纳米催化剂提供了信息和策略，指明了实现电化学 CO 转化的分子水平控制的新兴机遇。
