Enhancing ORR Performance of Bimetallic PdAg Electrocatalysts by Designing Interactions between Pd and Ag
Enhancing ORR Performance of Bimetallic PdAg Electrocatalysts by Designing Interactions between Pd and Ag
复制标题
DOI：
10.1021/acsaem.9b01920
复制
发表时间：
2020-03-23
影响因子：
6.4
通讯作者：
Cabrera, Carlos R.
中科院分区：
文献类型：
--
作者：
Betancourt, Luis E.;Rojas-Perez, Arnulfo;Cabrera, Carlos R.
使用欠电位沉积 (UPD) Cu 精确调节 Ag/C 的电子特性，并随后通过电偶位移沉积原子分散的 Pd 负载，从而形成坚固的双金属合金，在碱性介质中具有显着的氧还原反应活性。催化剂的具体设计和 Pd-Ag 的原子排列优于传统的 Pd/C 和 Ag/C 商业催化剂。沉积在 Ag/C 上的 Pd 的 ORR 活性是根据旋转圆盘电极伏安法研究确定的，结果显示与使用 Pd/C 获得的结果相比，Pd 质量活性增加了 2 倍。虽然扫描透射电子显微镜 (STEM) 与电子能量损失光谱 (EELS) 相结合探测了纳米颗粒的均匀性，但出色活性的根源可追溯到 Pd-Ag 界面的结构特性，如 X 射线吸收光谱 (XAS) 和 X 射线光电子能谱 (XPS) 所示。在界面处具有合适的银钯比几何排列的金属偏析导致性能提高，其中活性位点是氧键断裂的关键步骤。
Precise tuning of the electronic properties of Ag/C using under potentially deposited (UPD) Cu and subsequent galvanic displacement to deposit atomically dispersed loading of Pd resulted in a robust bimetallic alloy with significant activity for the oxygen reduction reaction in alkaline media. The specific design of the catalyst and atomic arrangement of Pd-Ag outperforms conventional Pd/C and Ag/C commercial catalysts. The ORR activity of Pd deposited onto Ag/C was determined on the basis of rotating disk electrode voltammetry studies, showing a 2-fold increase in Pd mass activities compared to results obtained using Pd/C. While scanning transmission electron microcopy (STEM) coupled with electron energy loss spectroscopy (EELS) probed the uniformity of the nanoparticles, the origin of the outstanding activity was traced to the structural properties of the Pd-Ag interface as shown by X-ray absorption spectroscopy (XAS), along with X-ray photoelectron spectroscopy (XPS). Segregation of metals with a suitable geometric arrangement of the Ag to Pd ratio at the interface resulted in an increased performance where the active sites were key steps of oxygen bond breaking.