Mezzavilla Stefano, Horch Sebastian, Stephens Ifan E L, Seger Brian, Chorkendorff Ib
SurfCat, Department of Physics, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark.
Current address: Department of Materials, Imperial College London, Royal School of Mines, London, SW72AZ, UK.
Angew Chem Int Ed Engl. 2019 Mar 18;58(12):3774-3778. doi: 10.1002/anie.201811422. Epub 2019 Feb 11.
An understanding of the influence of structural surface features on electrocatalytic reactions is vital for the development of efficient nanostructured catalysts. Gold is the most active and selective known electrocatalyst for the reduction of CO to CO in aqueous electrolytes. Numerous strategies have been proposed to improve its intrinsic activity. Nonetheless, the atomistic knowledge of the nature of the active sites remains elusive. We systematically investigated the structure sensitivity of Au single crystals for electrocatalytic CO reduction. Reaction kinetics for the formation of CO are strongly dependent on the surface structure. Under-coordinated sites, such as those present in Au(110) and at the steps of Au(211), show at least 20-fold higher activity than more coordinated configurations (for example, Au(100)). By selectively poisoning under-coordinated sites with Pb, we have confirmed that these are the active sites for CO reduction.
了解结构表面特征对电催化反应的影响对于开发高效的纳米结构催化剂至关重要。金是已知在水性电解质中将CO还原为CO最具活性和选择性的电催化剂。人们已经提出了许多策略来提高其固有活性。然而，活性位点性质的原子层面知识仍然难以捉摸。我们系统地研究了金单晶对电催化CO还原的结构敏感性。CO形成的反应动力学强烈依赖于表面结构。配位不足的位点，如Au(110)中存在的位点以及Au(211)台阶处的位点，其活性比配位更多的构型（例如Au(100)）至少高20倍。通过用Pb选择性地毒化配位不足的位点，我们证实了这些位点是CO还原的活性位点。
