Hitt Jeremy L, Li Yuguang C, Tao Songsheng, Yan Zhifei, Gao Yue, Billinge Simon J L, Mallouk Thomas E
Department of Chemistry, The University of Pennsylvania, Philadelphia, PA, USA.
Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY, USA.
Nat Commun. 2021 Feb 18;12(1):1114. doi: 10.1038/s41467-021-21342-w.
In the problem of electrochemical CO reduction, the discovery of earth-abundant, efficient, and selective catalysts is essential to enabling technology that can contribute to a carbon-neutral energy cycle. In this study, we adapt an optical high throughput screening method to study multi-metallic catalysts for CO electroreduction. We demonstrate the utility of the method by constructing catalytic activity maps of different alloyed elements and use X-ray scattering analysis by the atomic pair distribution function (PDF) method to gain insight into the structures of the most active compositions. Among combinations of four elements (Au, Ag, Cu, Zn), AuAgCu and AuZnCu were identified as the most active compositions in their respective ternaries. These ternary electrocatalysts were more active than any binary combination, and a ca. 5-fold increase in current density at potentials of -0.4 to -0.8 V vs. RHE was obtained for the best ternary catalysts relative to Au prepared by the same method. Tafel plots of electrochemical data for CO reduction and hydrogen evolution indicate that the ternary catalysts, despite their higher surface area, are poorer catalysts for the hydrogen evolution reaction than pure Au. This results in high Faradaic efficiency for CO reduction to CO.
在电化学CO还原问题中，发现储量丰富、高效且具有选择性的催化剂对于实现有助于碳中性能源循环的技术至关重要。在本研究中，我们采用光学高通量筛选方法来研究用于CO电还原的多金属催化剂。我们通过构建不同合金元素的催化活性图来证明该方法的实用性，并使用原子对分布函数（PDF）方法进行X射线散射分析，以深入了解最具活性组成的结构。在四种元素（Au、Ag、Cu、Zn）的组合中，AuAgCu和AuZnCu在各自的三元体系中被确定为最具活性的组成。这些三元电催化剂比任何二元组合都更具活性，相对于通过相同方法制备的Au，最佳三元催化剂在相对于可逆氢电极（RHE）为-0.4至-0.8 V的电位下，电流密度提高了约5倍。CO还原和析氢的电化学数据的塔菲尔曲线表明，尽管三元催化剂具有更高的表面积，但与纯Au相比，它们作为析氢反应的催化剂性能较差。这导致CO还原为CO的法拉第效率较高。
