Ma Zhonghua, Chen Chang, Cui Xiangzhi, Zeng Liming, Wang Lianjun, Jiang Wan, Shi Jianlin
State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China.
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China.
ACS Appl Mater Interfaces. 2021 Sep 22;13(37):44224-44233. doi: 10.1021/acsami.1c10518. Epub 2021 Sep 9.
Amorphous nanostructures usually exhibit special and intriguing catalytic activities, and the electrochemical performance can be tuned during operation. Herein, a facile approach of the self-activation of amorphous platinum (A-Pt) nanospheres has been applied to develop a durable and efficient hydrogen electrode catalyst toward both the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR), which was converted to crystalline counterparts and partially oxidized during the electrochemical cycling, leading to the self-activated enhancements of both HER and HOR activities with the decreased overpotential by 5 times and the increased hydrogen oxidation current density by 67%, respectively. Especially, in addition to 12 times higher mass activity compared to benchmark Pt/C, -activated A-Pt also demonstrated a lower HER overpotential even after 20 000 cycles than Pt/C. The significantly improved catalytic performance benefits from the rapid self-reconstruction processes (crystallization and oxidation) of the amorphous Pt during electrochemical cycling. This work shows the intriguing properties of the amorphous nanostructure and provides a new idea for designing an efficient electrocatalyst by phase engineering.
非晶态纳米结构通常表现出特殊且引人入胜的催化活性，并且其电化学性能在运行过程中可以调节。在此，一种非晶态铂（A-Pt）纳米球自活化的简便方法已被用于开发一种耐用且高效的氢电极催化剂，用于析氢反应（HER）和氢氧化反应（HOR），该催化剂在电化学循环过程中转变为晶态对应物并部分氧化，导致HER和HOR活性的自活化增强，过电位分别降低了5倍，氢氧化电流密度增加了67%。特别是，与基准Pt/C相比，活化后的A-Pt质量活性高出12倍，即使在20000次循环后，其HER过电位也比Pt/C低。显著提高的催化性能得益于电化学循环过程中非晶态Pt的快速自重构过程（结晶和氧化）。这项工作展示了非晶态纳米结构的有趣特性，并为通过相工程设计高效电催化剂提供了新思路。
