Huang Shuke, Li Jun, Wang Xiaosha, Kang Yongshuai, Zhao Yongjian, Wang Hu, Zhang Peixin, Zhang Lei, Zhao Chenyang
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518071, China.
ACS Appl Mater Interfaces. 2023 Mar 22;15(11):14447-14456. doi: 10.1021/acsami.3c00708. Epub 2023 Mar 13.
Direct formic acid fuel cells (DFAFCs) are considered promising sustainable power sources due to their high energy density, nonflammability, and low fuel crossover. However, serious CO poisoning and activity attenuation of the anodic formic acid oxidation reaction (FAOR) greatly restrict the output and durability of DFAFCs. Inspired by the specific relationship between the composition, type, and property of alloys, in this work, we synthesize a series of hybrid substitutional/interstitial quaternary alloys P-PdAuAg by means of a novel polyphosphide route to address these issues. Due to the simultaneous interstitial P-doping and metal (Au, Ag, Pd) co-reduction, the P-PdAuAg quaternary alloy obtained is only 3 nm in diameter with abundant defects. It not only achieves a new high mass activity of 8.08 A mg (6.78 A mg) but also maintains high stability in the high potential range and harsh reaction conditions. Both the activity and anti-poisoning ability are far exceeding those of the currently reported FAOR catalysts. Detailed density functional theory (DFT) calculations reveal that the superb electrochemical performances originate from the shift of the d-band center of Pd as a result of the synergistic electronic/ligand effects between Pd, Au, Ag, and P. The introduction of interstitial P inhibits the occurrence of an indirect reaction pathway on Pd, while Au and Ag suppress the adsorption of CO and optimize the sequential dehydrogenation steps, leading to boosted reaction kinetics and CO tolerance. This work pioneered a facile way for the synthesis of Pd-based substitutional/interstitial hybrid alloys, providing a promising means of further improving the performance of alloying catalysts.
直接甲酸燃料电池（DFAFCs）因其高能量密度、不可燃性和低燃料渗透而被认为是有前景的可持续能源。然而，严重的一氧化碳中毒和阳极甲酸氧化反应（FAOR）的活性衰减极大地限制了DFAFCs的输出和耐久性。受合金组成、类型和性能之间特定关系的启发，在本工作中，我们通过一种新颖的多磷化物路线合成了一系列置换/间隙混合四元合金P-PdAuAg来解决这些问题。由于同时进行间隙P掺杂和金属（Au、Ag、Pd）共还原，所获得的P-PdAuAg四元合金直径仅为3 nm且存在大量缺陷。它不仅实现了8.08 A mg（6.78 A mg）的新高质量活性，还在高电位范围和苛刻反应条件下保持了高稳定性。其活性和抗中毒能力均远远超过目前报道的FAOR催化剂。详细的密度泛函理论（DFT）计算表明，优异的电化学性能源于Pd的d带中心因Pd、Au、Ag和P之间的协同电子/配体效应而发生的移动。间隙P的引入抑制了Pd上间接反应路径的发生，而Au和Ag则抑制了CO的吸附并优化了连续脱氢步骤, 从而提高了反应动力学和CO耐受性。这项工作开创了一种简便的合成Pd基置换/间隙混合合金的方法，为进一步提高合金催化剂的性能提供了一种有前景的手段。
