Liu Kai, Ma Ming, Wu Longfei, Valenti Marco, Cardenas-Morcoso Drialys, Hofmann Jan P, Bisquert Juan, Gimenez Sixto, Smith Wilson A
Materials for Energy Conversion and Storage (MECS), Department of Chemical Engineering, Faculty of Applied Sciences , Delft University of Technology , Van der Maasweg 9 , 2629 HZ Delft , The Netherlands.
Laboratory for Inorganic Materials and Catalysis (IMC), Department of Chemical Engineering and Chemistry , Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven , The Netherlands.
ACS Appl Mater Interfaces. 2019 May 8;11(18):16546-16555. doi: 10.1021/acsami.9b01553. Epub 2019 Apr 29.
Au-Cu bimetallic thin films with controlled composition were fabricated by magnetron sputtering co-deposition, and their performance for the electrocatalytic reduction of CO was investigated. The uniform planar morphology served as a platform to evaluate the electronic effect isolated from morphological effects while minimizing geometric contributions. The catalytic selectivity and activity of Au-Cu alloys was found to be correlated with the variation of electronic structure that was varied with tunable composition. Notably, the d-band center gradually shifted away from the Fermi level with increasing Au atomic ratio, leading to a weakened binding energy of *CO, which is consistent with low CO coverage observed in CO stripping experiments. The decrease in the *CO binding strength results in the enhanced catalytic activity for CO formation with the increase in Au content. In addition, it was observed that copper oxide/hydroxide species are less stable on Au-Cu surfaces compared to those on the pure Cu surface, where the surface oxophilicity could be critical to tuning the binding strength of *OCHO. These results imply that the altered electronic structure could explain the decreased formation of HCOO on the Au-Cu alloys. In general, the formation of CO and HCOO as main CO reduction products on planar Au-Cu alloys followed the shift of the d-band center, which indicates that the electronic effect is the major governing factor for the electrocatalytic activity of CO reduction on Au-Cu bimetallic thin films.
通过磁控溅射共沉积制备了成分可控的金 - 铜双金属薄膜，并研究了其对一氧化碳电催化还原的性能。均匀的平面形态为评估从形态效应中分离出的电子效应提供了一个平台，同时将几何贡献降至最低。发现金 - 铜合金的催化选择性和活性与随可调成分变化的电子结构变化相关。值得注意的是，随着金原子比的增加，d 带中心逐渐远离费米能级，导致 *CO 的结合能减弱，这与在 CO 剥离实验中观察到的低 CO 覆盖率一致。*CO 结合强度的降低导致随着金含量的增加，CO 生成的催化活性增强。此外，观察到与纯铜表面相比，氧化铜/氢氧化铜物种在金 - 铜表面上不太稳定，其中表面亲氧性可能对调节 *OCHO 的结合强度至关重要。这些结果表明，电子结构的改变可以解释金 - 铜合金上 HCOO 生成的减少。一般来说，平面金 - 铜合金上作为主要 CO 还原产物的 CO 和 HCOO 的形成遵循 d 带中心的移动，这表明电子效应是金 - 铜双金属薄膜上 CO 还原电催化活性的主要控制因素。
