Gui Renjie, Cheng Han, Wang Minghao, Tai Xiaolin, Zhang Huijuan, Liu Congyan, Cao Xuemin, Chen Chen, Ge Min, Wang Huijuan, Zheng Xusheng, Chu Wangsheng, Lin Yue, Xie Yi, Wu Changzheng
Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, China.
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, China.
Adv Mater. 2024 Mar;36(11):e2307661. doi: 10.1002/adma.202307661. Epub 2023 Dec 20.
Pt-based fuel cell catalysts with excellent activity and stability for proton-exchange membrane fuel cells (PEMFCs) have been developed through strain regulation in recent years. Herein, this work demonstrates that symmetry-induced strain regulation of Pt surface of PtGa intermetallic compounds can greatly enhance the catalytic performance of the oxygen reduction reaction (ORR). With the strain environment varies derived from the lattice mismatch of analogous PtGa core but different symmetry, the Pt surface of the PtGa alloy and the Pt Ga (Pm m) precisely realize 0.58% and 2.7% compressive strain compared to the Pt Ga (P4/mmm). Experimental and theoretical results reveal that when the compressive stress of the Pt lattice increases, the desorption process of O* intermediates becomes accelerated, which is conducive to oxygen reduction. The Pt Ga (Pm m) with high symmetry and compressive Pt surface exhibit the highest mass and specific activities of 2.18 A mg and 5.36 mA cm , respectively, which are more than one order of magnitude higher than those of commercial Pt/C catalysts. This work demonstrates that material symmetry can be used to precisely modulate Pt surface stress to enhance the ORR, as well as provide a distinct platform to investigate the relationship between Pt compressibility and catalytic activity.
近年来，通过应变调控已开发出对质子交换膜燃料电池（PEMFC）具有优异活性和稳定性的铂基燃料电池催化剂。在此，这项工作表明，PtGa金属间化合物Pt表面的对称诱导应变调控可大大提高氧还原反应（ORR）的催化性能。由于类似PtGa核的晶格失配但对称性不同而导致应变环境变化，与PtGa（P4/mmm）相比，PtGa合金和PtGa（Pmm）的Pt表面精确实现了0.58%和2.7%的压缩应变。实验和理论结果表明，当Pt晶格的压缩应力增加时，O*中间体的解吸过程加速，这有利于氧还原。具有高对称性和压缩Pt表面的PtGa（Pmm）分别表现出最高的质量活性和比活性，分别为2.18 A mg和5.36 mA cm，比商业Pt/C催化剂高出一个多数量级。这项工作表明，材料对称性可用于精确调节Pt表面应力以增强ORR，同时提供一个独特的平台来研究Pt压缩性与催化活性之间的关系。
