Nanoporous Pd-Cu thin films as highly active and durable catalysts for oxygen reduction in alkaline media
Nanoporous Pd-Cu thin films as highly active and durable catalysts for oxygen reduction in alkaline media
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DOI：
10.1016/j.electacta.2021.138306
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发表时间：
2021-04
影响因子：
6.6
通讯作者：
Yu-duan Xie;Can Li;Ezer Castillo;Jiye Fang;N. Dimitrov
中科院分区：
文献类型：
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作者：
Yu-duan Xie;Can Li;Ezer Castillo;Jiye Fang;N. Dimitrov
为了提高钯铜薄膜在碱性介质中对氧还原反应的电催化性能，开发了一种简单的电化学腐蚀方法。采用电化学方法对预沉积的Pd-Cu薄膜进行脱合金处理，制备出纳米多孔Pd-Cu薄膜。扫描电子显微镜（SEM）与能量色散光谱，以确认在np结构中的Cu的残留量。相应制备的np催化剂显示出优异的ORR活性，在0.9 V vs. RHE的电位下高达1.11 A/mgPd，这分别是普通Pd膜和商业Pd/C催化剂的约22倍和6.2倍。通过扫描电子显微镜、氢欠电位沉积和CO剥离表征证实，ORR活性的增强归因于独特的多孔结构、大的Pd表面积以及残留Cu修饰的Pd电子结构。np Pd-Cu催化剂还显示出优异的耐久性，这表现为在碱性介质中10，000次电位循环后半波电位的可忽略的降低（4 mV负移）。这些研究结果提供了见解的合理设计的电催化剂的结构，利用电化学去合金化的方法，以实现高原子利用率和改善的催化性能。
A facile electrochemical etching approach was developed and implemented to enhance the electrocatalytic performance of Pd-Cu films for oxygen reduction reaction (ORR) in alkaline media. The nanoporous (np) Pd-Cu was synthesized through electrochemical de-alloying of pre-deposited Pd-Cu films. Scanning electron microscopy (SEM) with energy dispersive spectroscopy was employed to confirm the residual amount of Cu in the np structure. The accordingly prepared np catalysts showed excellent ORR activity up to 1.11 A/mgPdat a potential of 0.9 V vs. RHE which is around 22-times and 6.2-times higher than that of a plain Pd film and commercial Pd/C catalyst, respectively. The ORR activity enhancement is attributed to the unique porous structure, large Pd surface area, and modified electronic structure of Pd with residual Cu as confirmed by the SEM, hydrogen underpotential deposition, and CO stripping characterizations. The np Pd-Cu catalyst also showed excellent durability which is manifested by a negligible decrease in the half-wave potential (4 mV negative shift) after 10,000 potential cycles in alkaline media. These findings provide insights into the rational design of an electrocatalyst's structure utilizing an electrochemical de-alloying method to achieve high atomic utilization and improved catalytic performance.